Equalizers and methods of equalizing, wherein an equalizer may include includes n (where n is an integer ≧) biquad circuits each include an input node, a biquad band pass node and a biquad low pass node, a first summing circuit summing an output of the biquad band pass node of the nth biquad circuit and an output of the biquad low pass node of the nth biquad circuit, a second summing circuit subtracting the output of the biquad low pass node of the (n−1)th biquad circuit from the output of the first summing circuit and amplifying the summed result by a constant, and a third summing circuit summing an output of the second summing circuit and the output of the biquad low pass node of the nth biquad circuit, wherein the n biquad circuits are Gm-C biquad circuits each having transconductors connected in a self-feedback configuration to the biquad band pass node of the corresponding n biquad circuit. The equalizer may increase a filter bandwidth and/or maintain a specific boosting gain while reducing circuit size.

1. Field of the Invention
Example embodiments of the present invention relate to equalizers and methods of equalizing, and more particularly, to equalizers having a smaller size and/or a wider bandwidth.
2. Description of the Related Art
An equalizer used for continuous-time signal processing simultaneously performs a low pass filtering function and a function of boosting a high-frequency region of an input signal to equalize the input signal. In a DVD or HDD PRML read channel signal process, for example, the equalizer simultaneously carries out an equalizing function of making the pulse shape of a signal input from media stored in a DVD or HDD into a target pulse shape and a filtering function of reducing high-frequency noise input from a pre-amplifier and a VGA.
For processing signals input from high speed disc drive read channels and various media, an equalizer having a wide bandwidth and/or a high boosting gain may be desirable. An equalizer having lower consumption power and/or a smaller circuit area, for example, implemented as a system on chip (SOC) may also be desirable. Thus, it is difficult to design an equalizer having a wider bandwidth.
A wide bandwidth equalizer may use a switched-capacitor (SC) filler or a transconductor-capacitor (Gm-C) filter. A Gm-C filter has an open loop structure and is suitable for a high-frequency operation. A wide bandwidth equalizer may include a circuit for boosting high-frequency components. The −3 dB frequency of a Gm-C filter is determined by a ratio of transconductance (gm) to integrating capacitance (C), that is, gm/C. Thus, to increase the bandwidth of a Gm-C filter, the transconductance gm should be increased and the capacitance C should be decreased. The −3 dB frequency is a factor determining AC response characteristic of the filter and corresponds to a frequency at which the gain of the filter becomes −3 dB.
To increase the bandwidth of a Gm-C filter, an integrating capacitor having a smaller capacitance may be used. The integrating capacitor may be designed by scaling a normalized integrating capacitance determined based on a filter order and a filter type (for example, Bessel, Butterworth, Equiripple filters). The actual capacitance obtained by scaling a normalized capacitance with a desired factor must be larger than a parasitic capacitance. For example, when normalized capacitances of a third-order filter are C1=0.1, C2=0.2 and C3=0.3 and a scale factor is 5 p, the actual capacitances are 0.5 pF, 1.0 pF and 1.5 pF. If a parasitic capacitance, which is added to each integrating node caused by a plurality of transconductors connected in parallel with a circuit for boosting, is 1.0 pF, the scale factor must be larger than 10 p. This is because, when the scale factor is 5 p, there is no problem in the nodes to which C2 and C3 are connected but the capacitance of the node connected to C1, 0.5 pF, is smaller than the parasitic capacitance, 1 pF.
If there is no circuit for boosting connected to the node of C1 but exists only a parasitic capacitance of 0.4 pF caused by a plurality of transconductors, all the capacitances can be scaled even if the scale factor is 5 p when an integrating capacitance of 0.1 pF is added to the node of C1. However, the total capacitance can be increased or decreased according to a boosting algorithm to increase or decrease a chip size.
FIG. 1 is a circuit diagram of a conventional equalizer 100. Referring to FIG. 1, the conventional equalizer 100 is a 7th-order equalizer and includes a lossy integrator 102, three Gm-C biquad circuits 104, 106 and 108, and a boosting circuit 110. The equalizer 100 is of the equiripple type and constructed by adding the boosting circuit 110 to a 7th-order low pass filer.
Each of the three Gm-C biquad circuits 104, 106 and 108 includes a first transconductor 118 connected between an input node 112 and a biquad band pass node 114, a first capacitor 120 connected between the biquad band pass node 114 and a ground voltage, a second transconductor 122 connected between the biquad band pass node 114 and a biquad low pass node 116, a third transconductor 124 that is connected between the biquad band pass node 114 and the biquad low pass node 116 and forms a feedback loop with the second transconductor 122, a fourth transconductor 126 connected to the biquad low pass node 116 in a self-feedback configuration, and a second capacitor 128 connected between the biquad low pass node 116 and the ground voltage.
A biquad circuit is a second-order filter and may be composed of operational amplifiers or transconductors as shown in FIG. 1. When a plurality of biquad circuits are serially connected, a filter having a more than fourth order can be obtained.
The boosting circuit 110 boosts a high-frequency region of the equalizer and includes an inverting transconductor 130 connected between the input node of the first Gm-C biquad circuit 104 and the input node of the second Gm-C biquad circuit 106, and a non-inverting transconductor 132 connected between the input node of the second Gm-C biquad circuit 106 and the input node of the third Gm-C biquad circuit 108. A non-inverting transconductor has input and output signals having the same phase and an inverting transconductor has input and output signals having a phase difference of 180°.
The normalized capacitances of the 7th-order equiripple filter of FIG. 1 are represented in Table 1.
TABLE 1CapacitorNormalized capacitanceC11.1610C21.2795C30.5938C40.5224C50.6485C60.2133C70.8729
In the structure of the equalizer 100 shown in FIG. 1, the outputs of the transconductors 130 and 132 for boosting are connected to integrating nodes of capacitors C3 and C5, that is, the biquad low pass node of the first biquad circuit 104 and the biquad low pass node of the second biquad circuit 106. Accordingly, parasitic capacitances generated from the outputs of the transconductors 130 and 132 are added to the integrating nodes connected to the capacitors C3 and C5, and thus parasitic capacitances of the integrating nodes of the capacitors C3 and C5 are larger than parasitic capacitances of capacitors C1, C2, C4 and C6. Referring to Table 1, the equalizer 100 is not efficient with respect to capacitor sizes because the normalized capacitances of the capacitors C3 and C5 are smaller than the normalized capacitance of the capacitor C1 or C2. That is, a large parasitic capacitance is added to a node having a small normalized capacitance to increase a scale factor for making the actual total capacitance, and thus other integrating capacitances should be scaled with a large scale factor.
To produce a high-frequency filter using identical transconductors, the total capacitance of each integrating node must be small. The total capacitance of one integrating node is represented by Ctot=Cnor×Sf=Sint×Cpar, where Ctot denotes the total capacitance, Cnor denotes a normalized capacitance, Sf is a scale factor, Sint is an integrating capacitance connected to a circuit, and Spar is a parasitic capacitance added to the circuit.
An Nth-order filter has N integrating nodes, N integrating capacitances, N normalized capacitances, N parasitic capacitances and one scale factor. If the parasitic capacitance Cpar is 0 at each node, Cnor×Sf=Cint. However, Cint=Cnor×Sf-Cpar because the parasitic capacitance Cpar is not zero in the actual circuit.
For example, when Cnor2=1.2795, Cnor3=0.5938, Sf=3 p and Cpar=0 in a seventh-order filter, Ctot2=3.8385 pF and Ctot3=1.7814 pF. When Cpar2=2 pF and Cpar3=1.5 pF, Cint2=1.8385 pF and Cint3=0.2814 pF. When Cpar2=2 pF and Cpar3=2.5 pF, however, the second node is normally scaled but the third node is not properly scaled because Ctot3 is smaller than Cpar3. The scale factor Sf must be increased and thus all the seven integrating capacitances are increased. This increases circuit size.
In the equalizer 100 of FIG. 1, a boosting gain K is determined by a ratio of transconductance gmk of transconductors added to the equalizer 100 for generating zero to transconductance gm of transconductors used to constitute the filter. That is, K∝gmk/gm. Accordingly, when a large-size transconductor is used to constitute a high-frequency filter, gm is increased and thus transconductors for boosting should be increased in the same ratio to obtain a specific boosting gain K. Furthermore, the sizes of transconductors added to the filter should be further increased in order to raise the boosting gain K.
Accordingly, conventional equalizers may have a problem that its size is increased in order to increase its bandwidth, obtain a specific boosting gain at a high frequency and/or raise the boosting gain. That is, when transconductance is increased to widen the bandwidth of a Gm-C filter in a conventional equalizer, the total capacitance is increased and thus the bandwidth cannot be widened. When capacitances are reduced, integrating capacitances may become smaller than parasitic capacitance. When the integrating capacitances and transconductance are increased, chip size is increased. Furthermore, when a boosting gain is raised using the conventional equalizer, sizes of transconductors should be increased to result in an increase in the chip size.


A gray scale voltage generating circuit includes a first resistor ladder circuit, connected between a high voltage power supply terminal and a low voltage power supply terminal and having nodes for outputting respective reference voltages, a second resistor ladder circuit, connected between the high voltage power supply terminal and the low voltage power supply terminal, and plural voltage follower circuits, connected between the respective nodes of the second resistor ladder circuit and the respective nodes of the first resistor ladder circuit with first resistor provided between the n/2'th node voltage and the high voltage power supply terminal and a second resistor provided between the n/2+1'th node voltage and the low voltage power supply terminal.

In color liquid crystal display devices, the number of gray-scale levels to be displayed has been increasing in recent years. For example, the display device of 260 thousand colors by six bits is now being replaced with that of six million seven hundred thousand colors by eight bits. Even a display device capable of displaying ten billion colors by 10 bits is now on the market. Under these circumstances, the gray scale power supply is one of critical fundamental circuits which generate voltage adjusted to the characteristic of each particular liquid crystal panel.
In general, a six-bit product has five positive side amplifiers and five negative side amplifiers, whilst an eight bit product has nine positive side amplifiers and nine negative side amplifiers. These amplifiers are designed to achieve the power supply efficiency and are able to output the voltage up to the vicinity of the power supply voltage or up to the vicinity of the GND (ground) voltage.
Although the wide spread use is made of a dedicated IC of the gray scale power supply, there is a case wherein the gray scale power supply is provided in an LCD driver. In this case, since an amplifier needs to be composed by a CMOS, the margin of driving capability has not sufficient margin, and hence circuit-design skills and techniques are required.
Referring to FIG. 5, there is shown a conventional typical LCD source driver including a data register 1 for sampling 6-bit digital display signals R, G and B, a latch circuit 2 for latching 6-bit digital signals in synchronization with a strobe signal ST, a D/A converter 3 which is made up by N pieces of digital-to-analog converters connected in parallel, a liquid crystal gray scale voltage generating circuit 4 which has a gamma-conversion characteristic adjusted to the liquid crystal characteristic, and N voltage followers 5 for buffering the voltage from the D/A converter 3.
An LCD panel includes a plurality of thin film transistors (TFTs) 6 and a plurality of pixel capacitors 7. Each thin film transistor is provided at an intersection of a data line and a scanning line and has a gate and a source connected to the scanning line and to the data line, respectively, and each pixel capacitor has its one terminal and its other terminal connected to the drain of the associated TFT and to a COM terminal, respectively. In FIG. 5, the configuration for one row of the LCD panel is schematically shown. That is, the LCD panel includes, in actuality, a plural number of rows (M rows), each made up of N thin film transistors (TFTs). An LCD gate driver, not shown, sequentially drives gates of the TFTs in the respective lines. The D/A converter 3 D/A converts the 6-bit digital display signals output from the latch circuit 2 to analog signals to supply the resulting analog signals to the inputs of the N voltage followers 5-1 to 5-N. The output signals from the voltage followers 5-1 to 5-N are supplied through the TFTs 6-1 to 6-N, respectively, to liquid crystal elements, operating as pixel capacitors 7-1 to 7-N, respectively.
The liquid crystal gray scale voltage generating circuit 4 generates a plurality of reference voltages. The D/A converter 3 receives reference voltages and selects a reference voltage by a decoder formed by e.g. a ROM switch, not shown. The liquid crystal gray scale voltage generating circuit 4 includes e.g. a resistor ladder circuit, which are driven by voltage followers to decrease the impedance at each reference voltage point and to carry out fine adjustment of the reference voltage.
FIG. 6 is a diagram illustrating the configuration of a liquid crystal gray scale voltage generating circuit in which a resistor ladder circuit is driven by voltage followers (see Patent Documents 1 and 2). Referring to FIG. 6, the liquid crystal gray scale voltage generating circuit includes a resistor ladder circuit 10 (resistors R1, R2, . . . , Rn−2, and Rn−1), provided in an LCD driver, an external resistor ladder circuit 30 (resistors R1′, R2′, . . . , Rn−2′, and Rn−1′), a buffer amplifier unit 20 which are made up by n voltage followers which receive respective tap voltages of the external resistor ladder circuit 30 to output reference voltages V1 to Vn, and a constant voltage generator (Vr) 40. The n voltage followers of the buffer amplifier unit 20 are composed by OP amps(operational amplifiers) OP1, OP2, . . . OPn−1, and Opn. The ladder resistors R1′, R2′, . . . , Rn−2′, and Rn−1′ of the external resistor ladder circuit 30 are variable resistors for performing the adjustment of the voltage values supplied to the OP amps OP1, OP2, . . . OPn−1, and OPn. The adjustment of the voltage values is performed so that they becomes optimal to the characteristic of the liquid crystal panel.
In the liquid crystal gray scale voltage generating circuit, shown in FIG. 6, the reference supply voltages are the ground voltage GND and Vr. This reference supply voltage Vr is supplied by a constant voltage source 40, such as band-gap-reference voltage generator, which is provided outside the gray scale voltage generating circuit. The gray scale voltages Vn, Vn−1, Vn−2, . . ., V2, and V1 are ultimately determined by the ladder resistors R0′, R1′, R2′, . . . , Rn−2′, and Rn−1′.
That is,Vn=Vr.Vn−1=Vr{(Rn−2′+Rn−3′+ . . . +R0′)/(Rn−1′+Rn−2′+Rn−3′ . . . +R0′)}V1=Vr{R0′/(Rn−1′+Rn−2′+Rn−3′+ . . . +R0′)}
It is noted that, in case the resistance ratio of the ladder resistors R1, R2, . . . , Rn−2, and Rn−1, which are for internally determining the gray scale voltage, is equal to the resistance ratio of the ladder resistors R1′, R2′, . . . , Rn−2′, and Rn−1′, which are for externally determining the gray scale voltage, output currents of respective OP amps OP1, OP2, . . . and OPn−1 are zero.
However, the output current In of the n'th OP amp OPn, as counted from the GND side, is given in the source direction by the following equation (1):In=(Vn−V1)/(R1+R2+ . . . +Rn−1)=Io  (1)
On the other hand, the output current I1 of the first OP amp OP1, as counted from the GND side, is given in the sink direction by the following equation (2):I1=(Vn−V1)/(R1+R2+ . . . +Rn−1)=Io  (2)
Thus, there is a problem in the liquid crystal gray scale voltage generating circuit, shown in FIG. 6, that the output dynamic ranges of the OP amps OPn and OP1 are reduced due to the source output current In of the OP amp OPn and the sink output current I1 of the OP amp OP1, as indicated by the equations (1) and (2), respectively.
For solving the problem, the present Assignee has proposed the configuration shown in FIG. 7 or 8 in the Patent Document 2.
Specifically, an auxiliary resistor Rn is connected between a high voltage power supply terminal VDD and a ladder resistor Rn−1, whilst an auxiliary resistor R0 is connected between a low voltage power supply terminal GND and a ladder resistor R1, as shown in FIG. 7A. In other respects, the configuration is the same as that of FIG. 6. With the configuration of FIG. 7A, the source current of the voltage follower OPn on the high voltage power supply terminal VDD side is adjusted by the resistor Rn, whilst the sink current of the voltage follower OP1 on the low voltage power supply terminal GND side is adjusted by the resistor R0.
Auxiliary current sources I0 and In are provided in place of the auxiliary resistors R0 and Rn, respectively, as shown in FIG. 8A. It is noted that the auxiliary current sources I0 and In are set for satisfying the equations (1) and (2), respectively. With this circuit configuration, the source current and the sink current of the OP amps OPn and OP1 are made zero to enhance the output dynamic range, thereby facilitating the circuit design of the output stage in the OP amps.
[Patent Document 1]
JP Patent Kokai Publication No. JP-A-6-348235
[Patent Document 2]
JP Patent Kokai Publication No. JP-A-10-142582


The invention relates to building spherical panoramas for image-based virtual reality systems. The image-based spherical panoramas can be navigated in any desired view direction (360-degrees) by suitable three-dimensional image browsers or viewers. The method and system also includes computing the number of photographs required to be taken and the azimuth angle of the center point of each photograph for building a spherical environment map representative of the spherical panorama. The method and system also includes an algorithm for computing the accurate azimuth angles of these taken photographs and seaming them together to build the spherical environment map.

The present invention relates to building photographic panoramas of virtual reality and in particular to building spherical environmental maps utilizing some photographs.
In virtual reality systems, synthesis and navigation of virtual environments are usually accomplished using one of the following approaches: 1) three-dimensional modeling and rendering; 2) branching movies; and 3) image-based approach.
Although three-dimensional modeling and rendering is the traditional approach, creating the three-dimensional geometrical entities is a laborious manual process, and special hardware (e.g., a graphic accelerator) may be necessary for rendering, in real time, a highly complex scene.
The branching movies approach is used extensively in the video game industry. Multiple movie segments are connected together to depict spatial paths of selected branch points. This approach is limited in navigability and interaction, and also requires a large amount of storage space to store movies.
For rendering complex scenes, such as real-world scenery, the image-based approach is often considered to be the most reasonable and feasible approach. The image-based approach renders scenes within a fixed time as well as independently of rendering quality and scene complexity.
The image based approach uses an environment map, which is established from a collection of images and characterizes the appearance of a scene when viewed from a particular position. The environment map contains the pixel values used to display the scene. The image environment map is first wrapped onto an object surface having a certain geometry, such as a cube, a sphere, or a cylinder. Afterwards, by locating the viewing position at the geometrical center of the wrapped object, perspective-corrected views of scenes can be reconstructed from the image on the object surface during playback.
There are many types of environment maps for storing data including cubic maps, spherical maps, cylindrical maps, fish-eye or hemispherical maps, and planar maps. Some environments are capable of storing data of omni-directional scenes, while others cannot. Others have used two additional kinds of environment maps in experimental systems: 1) the textured cylinder-like prism, and 2) the texture sphere-like polyhedron (see e.g., W. K. Tsao, xe2x80x9cRendering scenes in the real world for virtual environments using scanned imagesxe2x80x9d, Master Thesis of National Taiwan University, Advisor: Ming Ouhyoung, 1996). Rendering methods for different types of environment maps are described in U.S. Pat. Nos. 5,396,583; 5,446,833; 5,561,756; and 5,185,667, all of which are incorporated herein by reference.
As for building image-based panoramas, commercially available software (e.g., the QuickTime VR authoring tool suite, from Apple Computer Inc.) can be used to create a seamless panoramic cylindrical image from a set of overlapping pictures. An improved method of a stitching method is described in Hsieh et al., U.S. Ser. No. 08/933,758, filed Sep. 23, 1997, which is incorporated herein by reference. Stitching together photographic images taken from a fish-eye lens is also described in the developer manual of InfinitePictures(trademark), Inc. (xe2x80x9cSmoothMove Panorama Web Builderxe2x80x9d, Developer Manual (Version 2.0) of InfinitePictures(trademark), Inc., 1996).
Spherical environment maps are used to store data relating to a surrounding scene. There exists many types of spherical environment maps. Spherical mapping mechanisms are described in U.S. Pat. Nos. 5,359,363, 5,384,588, 5,313,306, and 5,185,667, all of which are incorporated herein by reference. The major advantage of spherical mapping systems is that the environment map is able to provide users with 360 degrees of both horizontal and vertical pannings of views within the mapped sphere. However, a common problem with spherical mapping systems relates to image acquisition. Generally, to acquire the image for a spherical environment map, users usually require special and relatively expensive cameras having fish-eye lenses. Two types of particular interest are the xe2x80x9cspherical reflectionxe2x80x9d map and the xe2x80x9cparametric spherical environmentxe2x80x9d map.
A xe2x80x9cspherical reflectionxe2x80x9d map stores the image of an environment as an orthographic projection on a sphere representing a perfect reflection of the surrounding scene (Zimmermann U.S. Pat. No. 5,185,667). These images with circular shapes are all stored in respective square arrays of pixels. The major disadvantage of spherical reflection maps is that the orientations near the silhouette of the sphere (i.e., the ring-like shape when the sphere is orthographically projected on a sphere) are sampled very sparsely. This makes it more difficult to render the spherical reflection maps for omni-directional and interactive viewers.
The invention relates to building spherical panoramas or spherical environment maps for image-based virtual reality systems. The image-based spherical panoramas can be navigated in any desired view direction (360-degrees) by suitable three-dimensional image browsers or viewers.
In one aspect of the invention, a method of photographing pictures for building the spherical panoramas with a camera system includes determining a number of circles of latitude to build the spherical panorama on the basis of the focal length of the camera system, the height of photographic film used in the camera system, and an overlapping ratio between contiguous ones of the pictures, each circle of latitude including a series of contiguous pictures; and photographing the determined number of pictures.
The approach permits the use of a camera having a standard or wide-angled lenses rather than fish-eye lenses which are more expensive and less popular.
Embodiments of this aspect of the invention may include one or more of the following features.
Determining the number of circles of latitude includes calculating the following equation:   NumCirclesLandscape  =            [                                    180                        xc2x0                                              (                              100                -                k                            )                                    %            *                          [                              2                                                                      tan                                          -                      1                                                                                (                                          a                                              2                                                f                                                              )                                                              ]                                      -        1            ]        .
where:
a is the height of the photographic film;
f is the focal length of the camera system; and
k is the overlapping ratio between contiguous pictures.
Alternatively, the number of circles of latitude can be determined by calculating the following equation:   NumCirclesPortrait  =            [                                    180                        xc2x0                    -                      2                                                      tan                                  -                  1                                                                          (                                  b                                      2                                        f                                                  )                                              +                      [                          2                            k                            %              *                                                tan                                      -                    1                                                                                (                                      a                                          2                                            f                                                        )                                                      ]                                                (                          100              -              k                        )                              %          *                      [                          2                                                              tan                                      -                    1                                                                                (                                      a                                          2                                            f                                                        )                                                      ]                              ]        .
where:
a is the height of the photographic film;
b is the width of the photographic film;
f is the focal length of the camera system; and
k is the overlapping ratio between contiguous pictures.
In another aspect of the invention, a method of transforming photographic images of a panoramic scene into a spherical environment map includes warping each of the plurality of photographic images into a parametric spherical environment map; and image cutting each of the warped photographic images into a rectangular image based on an elevation angle of a predetermined sight direction.
This aspect of the invention provides a reliable and efficient approach for transforming photographic images into a spherical environment map. A spherical environment map can be linearly mapped using the spherical coordinate system, in which each pixel is specified in terms of the pixel""s azimuthal angle around the horizon and its elevation angle below the north pole, denoted by (xcex8, xcfx86). Based on angles (xcex8v, xcfx86v) which define a picture""s sight (or view) direction, a two-dimensional image of a picture can be transformed onto an image region of a spherical environment map using an image warping formula. This is regarded as one kind of coordinate transformation. Although each picture is taken based on the predefined sight direction, direction errors in taking pictures may exist. For computing the actual azimuth angles of camera sight direction, an additional coordinate transformation using the azimuthal coordinate system is performed. Using these computed azimuth angles, the picture images are seamed together into a spherical environment map utilizing an image stitching technique.
Embodiments of this aspect of the invention may include one or more of the following features.
During image cutting, the warped photographic images are cut either horizontally or vertically on the basis of the elevation angle of the sight direction for each of the warped photographic images. For example, if the elevation angle of the sight direction, relative to one of the poles, for a warped photographic image is less than 10xc2x0 or greater than 170xc2x0, the warped photographic image is cut into a rectangular region defined by side edges of the warped photographic image and either a bottom or a top edge of the warped photographic image, respectively. On the other hand, if the elevation angle of the sight direction for a warped photographic image is between 30xc2x0 and 150xc2x0, the warped photographic image is cut into a rectangular region defined by two opposing horizontal lines and two opposing vertical lines.
Warping each of the photographic images includes mapping each pixel of the warped photographic image from at least one pixel of an associated photographic image. The attributes (e.g., color) of each pixel of the warped photographic image are derived from at least one pixel of the associated photographic image.
In still another aspect of the invention, a method of stitching together a series of photographic images to build a spherical panorama, includes computing sight directions for each of the photographic images; adjusting the intensity of the photographic images to an intensity related to an average of the intensities of the photographic images; and stitching together contiguous ones of the photographic images.
Embodiments of this aspect of the invention may include one or more of the following features.
Computing sight directions includes performing both vertical and horizontal registration of contiguous photographic images. In one implementation, a correlation-based algorithm is used to compute image phase correlation for all possible positions of image alignment. The position with the minimum alignment difference is then selected. The results of performing horizontal and vertical registration are inspected with a software tool.
Vertical registering is used to derive vertical relationships between images. One approach for vertically registering contiguous photographic images includes rotating each photographic image 90xc2x0; image warping the rotated photographic image with xcfx86L set to 90xc2x0; performing horizontal registration of contiguous photographic images; and then determining sight directions from the image positions after image registration.
Horizontal registration is performed to derive horizontal relationships between images and is usually performed after vertical registration. The method can further include a second xe2x80x9cfine-tuningxe2x80x9d vertical registration.
Image blending of overlapping regions of the contiguous photographic images can also be performed. For example, intensity levels of pixels in the overlapping regions using the following equation:       I              (              r        i            )        =                              d          A          t                ·                  I                                (                          p              i                        )                              +                        d          B          t                ·                  I                                (                          q              i                        )                                              d        A        t            +              d        B        t
where:
pi is the location of a pixel from a first one of the photographic images;
qi is the location of a pixel from a corresponding second one of the photographic images contiguous with the first one of the photographic images;
dA is the distance between location pi and a boundary of the first one of the photographic images;
dB is the distance between location qi and a boundary of the second one of the photographic images;
I(pi) is the intensity of the pixel at location pi;
I(qi) is the intensity of the pixel at location qi; and
I(ri) is the resultant intensity of the pixel.
When the panorama is navigated, an image browser for viewing spherical panoramas can retrieve the scene image from the spherical environment map based on the desired direction of view.
Other aspects of the invention include systems for implementing the methods described above. In particular, the systems are for photographing pictures of a panoramic scene for use in building a spherical panorama, for transforming photographic images of a panoramic scene into a spherical environment map, and for stitching together a two dimensional array of the photographic images to build a spherical panorama. The systems include computer-readable media having computer instructions for implementing the methods described above.
A computer-readable medium includes any of a wide variety of memory media such as RAM or ROM memory, as well as, external computer-readable media, for example, a computer disk or CD ROM. A computer program may also be downloaded into a computer""s temporary active storage (e.g., RAM, output buffers) over a network. For example, the above-described computer program may be downloaded from a Web site over the Internet into a computer""s memory. Thus, the computer-readable medium of the invention is intended to include the computer""s memory which stores the above-described computer program that is downloaded from a network.
Other advantages and features of the invention will be apparent from the following description and from the claims.

Image-based method and system for building spherical panoramas

Industrial Technology Research Institute


A method and system are provided for determining a magnetic field using a mobile device. The method includes determining location information of the mobile device, obtaining magnetic field data based on the location information, determining orientation information of the mobile device and applying the orientation information to the magnetic field data to compute a magnetic field corresponding to the orientation of the mobile device.

A magnetometer is an instrument used to measure the strength and/or direction of the magnetic field in the vicinity of the instrument. Many electronic devices exist that utilize a magnetometer for taking measurements for a particular application, e.g. geophysical instruments, aerospace equipment, and mobile communications devices such as cellular telephones, PDAs, smart phones, tablet computers, etc., to name a few.
Mobile communication devices, such as those listed above, may only be interested in the Earth's magnetic field. For example, a compass application on a mobile communication device may only be interested in the direction of the Earth's magnetic field.
A mobile communication device typically operates in various different locations and under various circumstances. Changes in the environment in which the mobile communication device operates can affect the operation of the magnetometer. Furthermore, magnetic interference from the environment and/or components of the mobile communication device itself, can cause a magnetometer reading to deviate from the Earth's magnetic field. As such, the magnetometer reading of the mobile communication device may not accurately indicate the Earth's magnetic field.

System and method for determining a magnetic field using a mobile device


In a method and device for correction of a B0 field drift in a temperature map acquisition by magnetic resonance tomography, a fluctuation measurement is calculated per pixel from a number of magnetic resonance tomography phase images of an examination subject or from temperature maps derived therefrom. Using this fluctuation measurement, pixels of the phase images or temperature maps with low fluctuation are determined, and corresponding pixels of a phase image to be corrected or of a temperature map to be corrected are selected using the pixels determined as having low fluctuation. The phase image to be corrected or the temperature map to be corrected is adjusted to a reference phase image or a reference temperature map such that the selected pixels of the phase image to be corrected or of the temperature map to be corrected are calibrated to corresponding pixels of the reference phase image or of the reference temperature map.

1. Field of the Invention
The present invention concerns a method for correction of B0 field drift in a temperature map exposure by means of magnetic resonance tomography. The invention furthermore concerns a device to implement such a method.
2. Description of the Prior Art
An image representation of an examination subject—in particular the body of a patient—that graphically reproduces the spatial distribution of the temperature or of a temperature difference within the examination subject is designated as a temperature map. Such a temperature map can be acquired by means of a magnetic resonance (MR) tomography apparatus scanner.
The presentation of temperature maps that show the time change of the temperature distribution within a patient body is useful in the context of tumor ablation in interventional radiology. The tumor tissue to be removed is heated (and thus killed) non-invasively by the application of focused ultrasound or by the application of laser light or radio waves by means of a probe inserted into the patient's body.
In order to be able to continuously monitor the temperature in the patient body during such a procedure (more precisely, in the region of the tissue to be ablated), the procedure typically occurs either directly in an MR scanner or in immediate proximity thereto. The temperature monitoring ensues by generating temperature maps of the patient's body continuously or at regular intervals over a longer time span, typically 30 to 120 minutes.
The nuclear magnetic resonance frequency of hydrogen atoms (protons) in a water molecule (and thus in particular in the water molecules of the patient's body) exhibit a characteristic temperature dependency. This physical effect is typically utilized for non-invasive temperature determination by means of magnetic resonance tomography. As a result of this temperature dependency, temperature differences in the patient's body are manifested by a spatial variation of the phase of the magnetic resonance signal, that is represented in the form of complex numbers. Information about the temperature distribution in the patient body at the point in time of acquisition therefore can be obtained from an image known as a phase image, that reproduces this phase with spatial resolution.
Phase images that were acquired at the points in time to be compared are typically subtracted pixel-by-pixel from one another to determine the (spatially resolved) temperature difference in the patient body between different acquisition points in time. In interventional radiology, in particular a "heated" phase image (therefore a phase image acquired at a point in time during the procedure) is subtracted from an "unheated" phase image (i.e. a phase image acquired before the beginning of the procedure). The temperature difference between the two acquisition points in time is then calculated from the resulting difference image for each pixel. The generation of temperature maps by means of MR tomography is designated as (MR) thermometry.
The precision of a temperature map generated in such a manner, in particular the precision with which the temperature difference between two acquisition points in time at a specific location of the patient body can be determined from such a temperature map, is typically impaired by the B0 field drift. The B0 field drift is a slow variation of the basic magnetic field (B0 field) of the MR scanner that is used to generate the temperature map.
Variation of the B0 field also disadvantageously leads to a change of the proton resonance frequency to which the acquisition of a temperature map is tied (in terms of measurement). Like temperature changes in the patient body, variations of the B0 field thus directly affect the phase images, but temperature-dependent phase changes and B0 field-dependent phase changes cannot be differentiated from each other without additional measures. An error in the resulting temperature map that normally grows with increasing distance between the acquisition points in time thus arises due to the B0 field drift.
To correct the influence of the B0 field drift in temperature maps, it has previously been typical to identify spatial regions of the phase images to be compared—in which spatial regions no temperature change is to be expected between the acquisition points in time—and to use such regions as correction regions.
For B0 field drift correction, the correction regions in the phase images to be compared are calibrated to one another. In other words, one of the phase images (normally the phase image acquired later) to be compared is corrected such that the correction region of the corrected phase image coincides with the correction region of the other comparison image with regard to the phase values, so a temperature difference of zero results.
To produce such a correction region, usually a magnetic resonance phantom filled with water at room temperature is placed in the examination volume while each phase image is being acquired. Alternatively, a region of the patient's body in which no heating or cooling between the acquisition points in time is expected can be defined as a correction region. The correction regions are to be manually defined by the user in any case.
Both known methods for correction of the influence of the B0 field drift are relatively error-prone. In particular, displacement of the phantom or (if the correction region was defined in the patient's body) a change of the patient position between the acquisition points in time can lead to a greater error of the resulting temperature map as a resulting of incorrect B0 drift correction.
An error of the B0 drift correction can also result from the fact that an unintended temperature change nevertheless occurs in the correction region between the acquisition points in time. Such errors in particular occur when the correction region is selected in the patient's body.

Magnetic resonance tomography method and apparatus for correcting drift of the B0 field in a temperature map


Methods and circuitry are disclosed for decoding a keystream. A set of test bits is generated, and a set of attempted keystream bits are generated from differences between the test bits and an input set of cipher bits. A set of current keystream bits are generated from a current seed using a parallel feedback shift register, and the attempted keystream bits are compared to the current keystream bits. In response to attempted keystream bits being equal to the current keystream bits, the current keystream bits are fed back as a new current seed. In response to attempted keystream bits being not equal to the current keystream bits, the attempted keystream bits are fed back as the new current seed.

Encryption-based data transmission schemes generally encode data using a random key. The original data may be referred to as plain text, the encryption key referred to as the keystream, and the resulting encrypted data referred to as the cipher text. The terms bits will sometimes be used in place of text in this description to indicate the binary representation of the text.
A transmitter encodes data using a selected keystream, and a receiver decodes the data using the same keystream. In some applications the receiver may be initially unaware of the keystream used by the transmitter. In these applications, the receiver applies different keystreams to received cipher text until the cipher text is successfully decoded. The keystream may be determined from a training pattern that is sent by the transmitter and known to the receiver. Once the receiver has decoded the cipher text using a keystream and recognized the training pattern, the receiver is said to have locked onto the training pattern. Thereafter, that keystream provides the seed for subsequently generated keystreams.
Serial encryption circuitry is often implemented with a linear feedback shift register (LFSR) that generates a serially output keystream. The cipher text may be generated by applying an exclusive-or function to the bits of plain text in combination with bits of the keystream. The output bits of the keystream are also fed back as input to the first stage of the LFSR.
For an LFSR having n stages and that implements a complete sequence, the maximum time that a receiver may expend in locking onto the training pattern is 2n−1 cycles. For large keystreams this may be a performance issue.
With increasing speeds and increasing numbers of configurable resources, field programmable gate arrays (FPGAs) are becoming the device of choice to implement various application circuitry. However, an FPGA may be unsuitable to host a serial LFSR that is to operate at very high frequencies. Even though an FPGA may be unable to implement an LFSR operating at some highest clock-rate, the speed limitations of the FPGA may be ameliorated by multiplexing the LFSR output into a parallel representation.
One method of multiplexing the serial LFSR sequence into a parallel sequence is to clock the serial LFSR at a high rate, and then perform a serial to parallel conversion to the slower rate parallel version. This process is reversed to demultiplex the low-speed parallel version into the higher-rate serial sequence. This process may be expensive in terms of resources because it requires logic for both the serial LFSR and the serial to parallel conversion.
The serial to parallel conversion of an LFSR sequence may result in a number of possible variations of the encoded training pattern since the keystream may vary according to the time at which the serial keystream is parallelized. The possible variations in the parallel form of the training pattern may require many cycles for the decoder to lock on the training pattern because the decoder must attempt different keystreams with the variations in the training pattern.
The present invention may address one or more of the above issues.


A flying cycle apparatus comprises a fuselage and a pair of wings extending laterally from the fuselage to provide lift. A jet engine is mounted within the fuselage with the air intake thereof extending through the front of the fuselage. The jet engine has a jet exhaust extending through the rear thereof with one or more jet exhaust ports extending downwardly through the bottom thereof. The one or more jet exhaust ports provide vertical take off and landing capability. A pilot seat is positioned on top of the fuselage with the pilot seat being adapted to have a pilot's legs straddle the fuselage. The pilot seat if further adapted to have an occupant able to access to a control panel. The control panel has means for controlling the proportion of jet exhaust exiting from each of the jet exhaust and jet exhaust ports. The control panel further including a control joystick which allows the user to maintain a stable position during vertical take off and landing maneuvers and to turn and bank when flying.

There are a number of vertical take off and landing aircraft in operation including the Harrier jet fighter and the Osprey marine transport craft. However, such craft are combat aircraft and provide fully enclosed cockpits and transportation. There are no presently available aircraft which utilize an open cockpit or allow a pilot to straddle the fuselage.
The present invention is designed for use by the public for enjoyment, transportation and general fun. None of the known prior art disclose the combination set forth herein.


A vehicle obstacle detector (10) that is designed to alert the driver of a motor vehicle that the vehicle has encountered an obstacle. The detector (10) consists of an obstacle detector assembly (12) that includes a front probe (14) having a cavity (14b) that houses a piezoelectric element 14c. The probe (14) is attached to a flexible housing (16) that can be attached by means of a clamp (20) to the curb side of a vehicle or alternatively, the detector can be mounted to a wall (60) of a structure. The probe (14) produces electrical oscillations when the probe touches or scrapes against an obstacle. The oscillations are applied to an electronics control unit (30) that subsequently produces an alarm signal that energizes a visual and/or an audio alarm. The alarm may be located in the cab of a vehicle or on the wall when a wall mounted assembly (12) is employed.

Mechanical and electrical vehicle obstacle detectors and particularly curb detectors, have been in use for a long period of time. The curb detectors which are used primarily to facilitate parking a vehicle generally employ a flexible probe that is attached near the front and back wheels of the vehicle. The probes are adjusted to rub against an obstruction, such as a street curb, with a predetermined clearance between the obstruction and the vehicle.
Mechanical curb detectors alert a driver that an obstacle has been reached when a rubbing noise, made by the curb detector, is heard by the driver by mechanical transmission. When electrical/electronic detectors are used, an electrical signal is produced when the curb detector strikes or scrapes against an obstacle such as a curb. The generated signal operates a lamp and/or a buzzer located in the vehicle's driving compartment to alert the driver that an obstacle has been encountered.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention. However, the following U.S. patents were considered related:
______________________________________ U.S. PATENT NO. INVENTOR ISSUED ______________________________________ 4,967,180 Wang 30 October 1990 4,904,894 Henry 4,870,868 Gastgeb 3 October 1989 4,855,736 Hsu 8 August 1989 ______________________________________
The Wang patent discloses a pre-impact alarm apparatus that signals the driver of a motor vehicle that obstacles exist in the path of the vehicle when the vehicle is backing-up. The alarm apparatus consists of a flexible sensing bar that projects from the rear of the vehicle. The bar includes an electrical impact head that is electrically attached to a buzzer located within the vehicle. When the sensing bar impacts an obstacle, the impact head closes a set of contacts that energizes the buzzer.
The Henry patent discloses a hail sensor that uses a plurality of piezoelectric transducer positioned to produce an output signal when it is vibrated by a hailstone. The transducer output is supplied to a conventional signal processing circuit such as peak detectors and counters, which detect the electrical signal produced by the transducers.
The Gastgeb patent discloses a sensing device which produces a response when the point of impact between an object and a member occurs at a preselected location on the member. The sensing apparatus includes a piezoelectric sensor that produces an oscillatory electrical signal which is proportional to the vibration in the member generated by the collision between the object and the member. Appropriate circuitry is provided for analyzing the oscillatory electrical signal and for producing a response if the object impacted the member at a preselected location.
The Hsu patent discloses an electronic parking sensor apparatus having a base for attaching to a vehicle. The apparatus includes a flexible probe for contacting an impending obstacle. The probe is electrically attached to an electronics alarm unit that includes a filter circuit, an alarm circuit and is equipped with a pair of 1.5 volt cells that supplies the power to the alarm unit. The filter includes a timer for activating the alarm circuit when the electrical signal continues beyond a first interval which varies between 0.05 to 1.0 seconds. The timer also prevents activation of the alarm unit beyond a second longer interval that varies between 10 to 40 seconds. Separate front and rear transmitter units can operate on different signal frequencies for separately indicating front and rear contact with the obstruction.

Vehicle ostacle detector and alarm system


An approach is provided for supporting retrieval of a web page over a data network from a web site is disclosed. A downstream proxy communicating with a host executing a browser receives a request message from a browser to retrieve the web page. An upstream proxy parses the web page to determine an object embedded in the web page, wherein a promise list is generated specifying the embedded object that is to be pre-fetched according to a criterion. The promise list is transmitted to the downstream proxy, wherein the upstream proxy pre-fetches the embedded object from the web site. The upstream proxy determines whether to forward one of the pre-fetched embedded object to the downstream proxy based on a comparison of cookies associated with one of the pre-fetched objects supplied, respectively, by the browser and the web site. This approach as particular applicability in relatively high latency networks, such as a satellite communications system.

The maturity of electronic commerce and acceptance of the Internet as a daily tool by a continually growing user base of millions of users intensify the need for communication engineers to develop techniques for enhancing network performance. With the advances in processing power of desktop computers, the average user has grown accustomed to sophisticated multimedia applications, which place tremendous strain on network resources (e.g., switch capacity). Also, because the decrease in application response times is a direct result of the increased processor performance, the user has grown less tolerant of network delays, demanding comparable improvements from the network infrastructure. Therefore, network performance enhancing mechanisms are needed to optimize efficiency and reduce user response times. These mechanisms are imperative in systems with relatively high network latency, such as a satellite network.
FIG. 9 is a diagram of a conventional communication system for providing retrieval of web content by a personal computer (PC). PC 901 is loaded with a web browser 903 to access the web pages that are resident on web server 905; collectively the web pages and web server 905 denote a "web site." PC 903 connects to a wide area network (WAN) 907, which is linked to the Internet 909. The above arrangement is typical of a business environment, whereby the PC 901 is networked to the Internet 909. A residential user, in contrast, normally has a dial-up connection (not shown) to the Internet 909 for access to the Web. The phenomenal growth of the Web is attributable to the ease and standardized manner of "creating" a web page, which can possess textual, audio, and video content.
Web pages are formatted according to the Hypertext Markup Language (HTML) standard which provides for the display of high-quality text (including control over the location, size, color and font for the text), the display of graphics within the page and the "linking" from one page to another, possibly stored on a different web server. Each HTML document, graphic image, video clip or other individual piece of content is identified, that is, addressed, by an Internet address, referred to as a Uniform Resource Locator (URL). As used herein, a "URL" may refer to an address of an individual piece of web content (HTML document, image, sound-clip, video-clip, etc.) or the individual piece of content addressed by the URL. When a distinction is required, the term "URL address" refers to the URL itself while the terms "web content", "URL content" or "URL object" refers to the content addressed by the URL.
In a typical transaction, the user enters or specifies a URL to the web browser 903, which in turn requests a URL from the web server 905 using the HyperText Transfer Protocol (HTTP). The web server 905 returns an HTML page, which contains numerous embedded objects (i.e., web content), to the web browser 903. Upon receiving the HTML page, the web browser 903 parses the page to retrieve each embedded object. The retrieval process requires the establishment of separate communication sessions (e.g., TCP (Transmission Control Protocol) connections) to the web server 905. That is, after an embedded object is received, the TCP connection is torn down and another TCP connection is established for the next object. Given the richness of the content of web pages, it is not uncommon for a web page to possess over 30 embedded objects. This arrangement disadvantageously consumes network resources, but more significantly, introduces delay to the user.
Delay is further increased if the WAN 907 is a satellite network, as the network latency of the satellite network is conventionally a longer latency than terrestrial networks. In addition, because HTTP utilizes a separate TCP connection for each transaction, the large number of transactions amplifies the network latency. Further, the manner in which frames are created and images are embedded in HTML requires a separate HTTP transaction for every frame and URL compounds the delay.
Based on the foregoing, there is a clear need for improved approaches for retrieval of web content within a communication system. There is also a need to utilize standard protocols to avoid development costs and provide rapid industry acceptance. There is a further need for a web content retrieval mechanism that makes the networks with relatively large latency viable and/or competitive for Internet access. Therefore, an approach for retrieving web content that reduces user response times is highly desirable.

System and method for pre-fetching content in a proxy architecture


A novel control device for a personal computer which is manipulated by a user's feet. The control device is intuitively manipulated by application of the appropriate pressure to the control device via two pedals for the user's feet. At any one time, the control device may be manipulated such that the control device moves in three distinct directions: the device pivots forwards or backwards, rotates left or right, and dips to the left or to the right. For each movement in a distinct direction, the control device generates an input for a personal computer.

A foot pedal is known as a conventional manipulating member which is operated by a user's foot. A foot pedal is operable in the push-in direction. A device, such as a personal computer, is designed or programmed to carry out a specified operation according to the detected push-in amount of the pedal. In the field of user interface devices for computer game applications, it has been a practice to employ foot pedals as input devices particularly for driving and flight control computer games.
A typical computer game will assign one or more different inputs to a corresponding action within the game. As computer games become more involved and complex, more inputs are required to control the actions within the game. Often players must rely on their keyboards and inconvenient or awkward key layouts to provide the necessary inputs. The repetitive nature of key inputs required by video games amplifies the discomfort experienced from using key layouts not adjusted for the hand ergonomics of an individual game player. Further, it is often not intuitive for a game player to press a key in order to effect game actions, for example, to rotate a virtual soldier surveying a battlefield or to cause a virtual plane to turn in flight.
The use of prior art foot devices has alleviated some of these problems. However, a drawback of the conventional foot pedal is the fact that the foot pedal has only one degree of freedom, namely in the push-in direction. This limits the number of inputs that the foot pedal can generate to control the actions of a computer game and a player using the foot pedal remains largely dependent on a computer keyboard or joystick.
There are foot control devices in the art which expand the functionality of conventional foot controllers. U.S. Pat. No. 5,583,407 discloses a foot pedal which produces three inputs. The pedal generates input based on forward and backward movement in a horizontal plane, pivotal movement and rotational movement around a vertical axis.
U.S. Pat. No. 5,552,807 discloses a foot pedal assembly with two pedals. The assembly generates three inputs for a computer based on independent pivoting of the pedals and the relative position of the pedals in a horizontal plane.
The above mentioned patents fail to provide an intuitive control interface for a user whereby the user can generate input for a computer by effecting roll, yaw and pitch rotation on a single device.
Accordingly, there is a need for an improved tri-axis foot controller device.


Object of the invention is an anodic structure for mercury cathode cells for the industrial electrolysis of sodium chloride. The new structure is constituted by a grid array comprising a multiplicity of vertically disposed and mutually parallel titanium blades, covered by an electrocatalytic coating specific for the discharge of chlorine. The ratio between the thickness and the height of the blades is comprised between 1:16 and 1:100 and the ratio between the surface of free passage between the blades and the projected surface is comprised between 15:17 and 25:30. The new grid array is perpendicularly fixed to new or existing frames having the function of mechanical support and current conduction to the grid array. Scope of the invention is simultaneously reducing the energetic consumption of the cell and the costs for restoring the exhausted electrocatalytic coating.

The production of chlorine and sodium hydroxide (chlor-alkali), about 45 millions of tons of chlorine per year, is carried out in electrolytic cells of different kinds, among which the mercury cathode electrolytic cell is of particular relevance, accounting for a production of about 12 millions of tons of chlorine per year.
In FIG. 1 a typical structure of a cell of this kind is outlined, consisting in an iron case (1) on whose bottom (2) the mercury amalgam (3) constituting the cathode flows. The anode is made by a multiplicity of electrodes shaped as a grid array (4), supported by mobile frames (5), preferably controlled by microprocessors having the purpose of regulating the interpolar gap, which may vary during the cell operation.
As 12 millions of ton chlorine/year are produced in cells at the following average operative conditions:
Current density:10kA/m2Anode/cathode voltage:4.05VFaradaic yield:96%Energy consumption:3185kWh/ton Cl2this kind of technology involves a consumption of about 38 millions of MWh/year.
In consideration of the high amount of involved energy and of the continuous increase in the cost of electricity, the cell technology has been remarkably enhanced in the course of the years, with the aim of reducing the energetic consumption, representing the most relevant item in the production costs.
Among the numerous technological innovations which contributed the most to decrease the energetic consumption, the replacement of the graphite consumable anodes with the metallic anodes has to be emphasised: the latter are typically made of titanium or other valve metal, coated with electrocatalytic material generally based on noble metals and/or oxides thereof. This type of anode, an example of which is given in U.S. Pat. No. 3,711,385, is still commercialised under the trade-mark DSA® by De Nora Elettrodi S.p.A, Italy.
It consists in a metallic structure comprising one frame and one grid array, overlapped and mutually welded or somehow fixed; the frame performs the function of mechanical support and of element of direct electric current distribution to the surface of the grid array, which is coated with an electrocatalytic film specific for the chlorine evolution reaction, and constitutes the anodic active surface.
The geometry of the grid array plays a role of great importance on the efficiency of the electrolysis process and on the energetic consumption of a cell as it influences, in a determining way, both the voltage and the faradaic yield thereof. In fact, the anode/cathode voltage of a cell, expressed as Volts, can be calculated by means of the relationship:V anode/cathode=3.15+Kf×J wherein J is the current density impressed to carry out the electrolytic process, expressed as kA/m2, and the Kf term (o "Key factor") incorporates all the components of resistive origin. The most important factors of such resistive components, namely the ohmic drop within the anodic structure, the ohmic drop in the electrolyte due to the bubble effect, and the ohmic drop in the electrolyte due to the interpolar gap, all depend from the anodic geometry; it is one of the main objects of the invention, in particular, to minimise the two latter factors.
The bubble effect is a measure of the increase of ohmic resistance in the electrolyte due to the gas bubbles developing on the anodic surface of the grid array and interrupting the electric continuity within the electrolyte itself. In particular, the bubble effect mainly depends on the number and size of the gas bubbles that are generated upon the anodic surface of the grid array and stagnate on the immediate vicinity thereof between the anode and the cathode; it further depends on the bubble ascending velocity, and on the descending velocity of the degassed electrolyte.
In summary, the bubble effect depends from the actual current density on the anodic surface (which determines the amount of bubbles developing per unit time), from the grid array geometry (which determines the ratio between actual working surface whereupon the gas is evolved and projected surface, as well as the gas withdrawal resistance), and from the optional added devices directed to improve the fluid dynamics. In particular, it is a first object of the present invention to provide an anodic grid array geometry producing a bubble effect minimisation.
Even in the absence of bubble effect, the ohmic drop within the electrolyte is directly proportional to the interpolar gap, so that it is extremely important to bring the anodic surface as close as possible to the mercury cathode, adjusting the gap between anode and cathode surfaces in a progressive fashion. It is however necessary to maintain a certain margin of safety, to avoid the mercury touching in some points the anodic surface, causing hazardous short-circuiting phenomena. For this reason, it will be possible to maintain as lower the interpolar gap as better is the planarity of the anodic structure. It is a further object of the present invention to provide an anodic grid array geometry with enhanced planarity characteristics with respect to the prior art.
In the most recent industrial cells, operating in ideal conditions, the Kf is normally comprised between 0.065 and 0.085 V m2/kA, depending on the cell size, the type of anode and the system of interpolar gap adjustment the cell is equipped with, whereof:    ˜0.0070–0.0080 V m2/kA are attributable to the ohmic drop within the anodic structure.    ˜0.0310–0.0410 V m2/kA are attributable to the bubble effect in correspondence of the anodic surface.    ˜0.0270–0.0360 V m2/kA are attributable to the ohmic drop in the electrolyte, as a function of the interpolar gap.
In other words, about 10% of Kf is attributable to the anode structure, about 50% to the bubble effect, and the remaining 40% to the interpolar gap.
For a given cell and at given process conditions, the minimum obtainable Kf is therefore a property of the anode, to a large extent attributable to the grid array characteristics (in the order of about 90%), as it depends from the width of the region affected by the bubble effect and from the planarity of the grid array itself.
For this reason, since the introduction of the metallic anodes, the grid array has been the object of several inventions, among which are recalled for their industrial relevance:                The cited metallic anode of U.S. Pat. No. 3,711,385, which in the earliest industrial embodiments comprised a grid array made of meshes, or more commonly of a multiplicity of titanium rods of about 3 mm diameter and 4.5 mm pitch, disposed in parallel, and supported by a current distributing frame, in its turn made of rectangular titanium conductors. Although enjoying a remarkable success at the time of its introduction, this configuration presented some big limitations, due both to the bubble effect and to the shielding effect of the rods on the cathode surface, with consequent difficulties of electrolyte circulation and of gas withdrawal when operating at high current density and reduced interpolar gap. The best known industrial results with this type of anode, commonly called "Rod type anode", operating at 10 kA/m2, are the following:
Anode/cathode voltage:4.00VKf:0.085V m2/kAFaradaic yield:~96%Energy consumption:3146kWh/ton Cl2
With the purpose of overcoming these drawbacks, U.S. Pat. No. 4,263,107 discloses hydrodynamic baffles, mounted on the upper part of the grid array, which generate convective motions so as to reduce the bubble effect, improve the fluid dynamics and ensure an effective renewal of the electrolyte.
The shielding effect of the rods has been subsequently reduced with the introduction of the invention disclosed in U.S. Pat. No. 4,364,811 according to which a grid array made of a multiplicity of rectangular strips, about 1.5 mm thick, 5 mm high and 4.0 mm spaced, defined as blades, arranged vertically respect to the cathode, was coupled to a frame of the prior art. The best known industrial results with this type of anode, operating at 10 kA/m2, are the following:
Anode/cathode voltage:3.90VKf:0.075V m2/kAFaradaic yield:~96%Energy consumption:3067kWh/ton Cl2
Even better results were obtained by coupling the hydrodynamic means of U.S. Pat. No. 4,263,107 to a grid array made of triangular strips, with their vertex facing the mercury cathode, as disclosed in the Italian Patent n°1.194.397. This new configuration, in which said triangular strips have, as typical dimensions, 2.2 mm base, 3.7 mm height, rounded vertex of 0.5 mm diameter and pitch (intended as distance between the axis of two consecutive strips) 3.5 mm, has brought to an important reduction of the bubble effect and of the shielding effect of the rods, and to a sensible improvement of the fluid dynamics.
The best industrial results obtained with this type of anode, still commercialised by De Nora Elettrodi S.p.A under the trade-mark RUNNER®, operating at 10 kA/m2, are the following:
Anode/cathode voltage:3.80VKf:0.065m2/kAFaradaic yield:~96%Energy consumption:2988kWh/ton Cl2
An alternative solution was proposed in U.S. Pat. No. 5,589,044, which discloses a frame similar to the previous ones, coupled to a grid array made of a multiplicity of rectangular strips and specially configured with the purpose of increasing the actual surface in correspondence of the vertical sides, and of decreasing the bubble stagnation effect on the surface facing the cathode. Although the results obtained with this kind of grid array are better than those obtained with the grid array of U.S. Pat. No. 4,364,811, they still remain inferior to those obtained with the grid array of IT 1.194.397.
The above described grid array configurations of the prior art, different in terms of hydrodynamic properties, bubble effect and shielding effect on the cathode, have however two different aspects in common:                the overall anodic surface planarity is hampered by the fact that the tolerances relative to the multiplicity of elements constituting the grid array (rods, blades or strips) and to the welds needed to fix the latter to the frame add up to the tolerances related to the frame itself. For all the grid arrays of the prior art, the typical tolerances along the anodic surface range between 0.5 and 1 mm, although recurring to rather controlled and sophisticated (and thus costly) machining.        the restoration of the catalytic properties of exhausted electrodic structures (to be repeated with cycles ranging from 2 to 5 years, depending on the operative conditions of the plant) involves complex and very expensive working consisting in the removal of the exhausted coating with mechanical (sandblasting) and chemical (etching) means frequently producing mechanical distortions; in some cases therefore, additional working is needed for restoring the planarity of the grid array, before (or after) providing a novel catalytic coating. The performances of a reactivated anode are virtually never quivalent to those of an anode of new construction, both because the planarity reinstatement is never perfect, and because the removal of the exhausted coating cannot be sometimes completed, or because the material constituting the grid array itself undergoes morphological changes that are not totally reversible. Finally, it is mandatory to remove the whole electrocatalytic coating even if just part of it has been consumed, in order to recover the full operability of the active surface. This involves a remarkable and useless consumption of matter consisting in extremely expensive precious metals such as ruthenium, iridium, platinum, and so on.

Anodic structure for mercury cathode electrolytic cells description of the invention


A method, apparatus and computer program product for determining customer routing in a call center is presented. Information relating to a customer in a communication session with the call center is recorded. The information relating to the customer in a communication session with the call center is evaluated and a determination made whether to transfer the customer to a generalist. The customer is transferred to a generalist when a result of the determining is that the customer should be transferred to a generalist and the customer is not transferred to a generalist and when the result of the determining is that the customer should not be transferred to a generalist.

Call centers are systems in which a person can communicate to receive information. Such communication can include, but is not limited to, telephone calls, Internet access, email, and FAX. A call center can include one or more interactive voice response (IVR) systems. The one or more IVRs provide automatic branching voice queries to which the caller responds with button pushes on a telephone keypad or with voice responses on a telephone. The call center may be provided having only the one or more IVR systems, or alternatively, it is also provided having human agents. For example, at the end of the IVR branching voice queries, the caller can be directed to press zero to speak to an agent. The call center can also include one or more database server computers, one or more database storage areas, one or more web server computers, and one or more email server computers.

Method and apparatus for determining customer routing in a call center


An apparatus and method for controlling the location of pages in a system having multiple processors and multiple main memory. Local and remote accesses to main memory are monitored and when remote accesses exceed local accesses in a predefined period, steps to alleviate the volume of remote accesses are undertaken. The steps may result in the relocation of a memory page, replication of a memory page (for read only pages) and relocation of a process.

Computer systems having multiple processors each with an associated main memory are known in the art and include the class of computer referred to as non-uniform memory access (NUMA) machines.
When a processor in one of these systems requires data from an external memory, for example, a magnetic or optical disk, a call is made to that memory and the requested data is loaded into the main memory of the requesting processor. If the same data is needed by a second processor, then a remote access over the system bus is performed by the second processor to read the data from the main memory of the first processor. If the subject data is required more often by the second processor than the first processor, then system performance is degraded by requiring the second processor to continually perform a remote access, and not transferring the data to the main memory of the second processor. Failure to recognize that the requested data is read only and may therefore be copied to the main memory of the second processor also degrades performance.

Memory page location control for multiple memory-multiple processor system


An LED package has a light emitting element, a first optical section that is disposed around the light emitting element, and a second optical section that is disposed around the first optical while being separated from the first optical section. A gap is formed between the first and second optical sections. The gap allows part of light emitted from the light emitting element to be radiated from the first optical section as nearly parallel light converged in the direction perpendicular to the center axis of the light emitting element. The second optical section includes a reflection surface to reflect the nearly parallel light in the direction parallel to the center axis of the light emitting element.

1. Field of the Invention
The invention relates to an LED package and, particularly, to an LED package to radiate light emitted from a light emitting diode (hereinafter referred to as LED) through an optical system in a predetermined direction and range.
2. Description of the Related Art
Conventionally, a lens-type LED package is well known that uses a light emitting element as light source and is designed to radiate light emitted from the light emitting element in a predetermined direction while controlling its lighting distribution by using an optical system (e.g., Japanese patent application laid-open No.8-107235 (prior art 1)).
However, in the lens-type LED package, it is impossible to secure a sufficient solid angle of lens surface to the light emitting element when it is provided with an optical surface shape to enhance the convergence performance. Therefore, it can only control about 30% of light emitted from the light emitting element and, thus, cannot offer a high efficiency of external radiation. So, prior art 1 discloses an LED package that is provided with a reflection surface around the light emitting element.
FIG. 1 is a cross sectional view showing the LED package disclosed in prior art 1.
The LED package is composed of an LED 60 as light source and a lens 61 to radiate converging light L emitted from the LED 60.
The lens 61 has a cylindrical recess 61A formed at the center of a nearly truncated cone, a semispherical convex lens 61B provided in the recess 61A, a space 61D with a circular cross section formed at a minor bottom face 61C, and a reflection surface 61E to form its side face. The LED 60 is disposed at the center of space 61D.
In this LED package, light emitted from the LED 60 is radiated parallel to the center axis of lens 61 while being is converged by the convex lens 61B. Also, light emitted in the direction of reflection surface 61E from the LED 60 is totally reflected on the reflection surface 61E and is then radiated parallel to the center axis of lens 61. Thus, since light emitted from the LED 60 is radiated parallel to the center axis of lens 61 based on total reflection and convergence, the lighting intensity at a point of equal distance can be increased.
However, the conventional LED package needs to use a large reflection mirror so as to efficiently control light not to be entered to the lens. Namely, as shown in FIG. 1, the reflection surface 61E needs to be further extended to a high level so as to efficiently control light not to be entered to the lens. A solid angle A of reflection surface 61A to the light emitting element 51 corresponding to that extension is big and the radiation intensity of light emitting element 51 is also intensive in this direction. Therefore, the amount of light to be controlled by the extension becomes considerable.
On the other hand, when using such a large reflection mirror, the diameter DL of lens to the outer diameter DW becomes relatively small. If the outer diameter DW is set small, then the homothetic ratio of lens diameter to emission area of light source has to be improper and, therefore, a problem is generated that, due to the lowering of convergence performance, it becomes impossible to radiate light with sufficient brightness in a desired direction and range. In addition, when the light source (LED) is enlarged according to the demand for high brightness or high output and its emission area is thereby enlarged, the homothetic ratio becomes improper. Thus, the same problem is generated.
Meanwhile, another LED package is suggested that uses a total reflection at its radiation surface to radiate light reflected on its reflection surface so as to offer a lower profile as well as enhancing the external radiation efficiency. However, in such an LED package, incident light to the reflection surface needs to have two optical paths and, therefore, a high convergence performance cannot be obtained.


A backrest for a vehicle seat includes a backrest frame, which is surrounded by a cover and has an upper backrest with an adjustable inclination. An additional frame is hinged so as to be pivotable about a pivot axis to a side plate, the cover, or the backrest frame. The pivot axis is arranged in an upper region of the backrest, and the additional frame extends upwards from the pivot axis in the installed position of the backrest. The additional frame can be secured in different angular positions in relation to the backrest frame, and, thus, a variable gap forms between the additional cover of the additional frame and the cover of the backrest frame.

The invention relates to a backrest for a vehicle seat with a backrest frame, which is surrounded by a cover and includes an upper backrest with an adjustable inclination.
The state of the art discloses backrests of this type in a variety of different embodiments. For example, DE 199 10 666 A1 discloses a vehicle seat, which has a seat section, a backrest and a headrest. The backrest is divided into two backrest sections, which can be pivoted about a horizontal axis in relation to each other. In this case, the upper backrest section bears a vertically adjustable headrest. The backrest, disclosed in DE 199 10 666 A1, is designed such that, during a rear end collision, the upper backrest section folds down in the forward direction against the lower backrest section. To this end, during a rear end collision the passenger, sitting on the vehicle seat, applies pressure to a mechanism in the lower region of the lower backrest section. The result of this action is that the upper backrest section along with the entire headrest, which is mounted thereon, is pivoted forwards. The drawback with this approach is that the cost of constructing such a design does not justify its use in the case of a seat with an integrated seat belt, where a seat belt D-ring is attached on the upper backrest section, because during a collision the passenger is pushed with enormous forces into the seat belt, and, hence these forces act on the pivot device between the upper and lower backrest section. In that case, the adjusting and locking devices between the upper and the lower backrest sections would have to be made very strong.
Another possibility that is disclosed in the state of the art for adjusting the inclination of the upper backrest section—thus, in the region of the shoulder blade—in relation to the lower backrest section is based on a totally different principle. In the case of such seats a single backrest frame is used that extends over both afore-mentioned regions of the backrest. Then the upper region of the backrest includes an inflatable body, which can be filled with air or can be deflated. In this way, the inclination of the upper backrest section is changed in relation to the lower backrest section as a function of how much air is present in the respective inflatable body. Since in this case a one-piece backrest frame is used, a seat belt D-ring can be fastened to this backrest frame, because there does not have to be a pivot axis, which is mechanically very stable, between the two sections of the frame. Therefore, such a construction can be used even in the case of a seat with an integrated seat belt. However, the drawback with this design is that it is very ineffective and slow. In addition, air conditioning functions in the vehicle seat can be realized only in partial areas thereof.
The object of the invention is to provide a backrest with an upper seat back with an adjustable inclination. This backrest withstands both high seat belt loads and can also be quickly adjusted. Moreover, it is not associated with a restriction on air conditioning functions.
This object is achieved with a backrest for a vehicle seat with a backrest frame, which is surrounded by a cover and includes an upper backrest having an adjustable inclination. An additional frame is hinged so as to be pivotable about a pivot axis on a side plate or to the cover or the backrest frame. The pivot axis is arranged in the upper region of the backrest, and the additional frame extends upwards from the pivot axis in the installed position of the backrest. The additional frame can be secured in different angular positions in relation to the backrest frame, and, thus, a variable gap forms between the additional cover of the additional frame and the cover of the backrest frame. Advantageous designs of the invention are described herein.
Owing to the fact that an additional frame is mounted on the otherwise continuous and one-piece backrest, in particular, a one-piece backrest frame, it is possible to also mount a seat belt D-ring on the backrest frame, which absorbs high seat belt forces. The pivotable hinge attachment of the additional frame on a side plate, the cover or the backrest frame can be carried out very easily, because it does not have to absorb any seat belt forces whatsoever. Owing to the fact that the additional frame can be secured in different angular positions relative to the backrest frame, good flexibility is guaranteed when a unique adjustment is made with respect to the current passenger. As a result, a variable gap forms between the additional cover of the additional frame and the cover of the backrest frame. In an extreme position, this gap can be reduced down to zero.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.

Backrest for a vehicle seat with an upper backrest having adjustable inclination

Bayerische Motoren Werke Aktiengesellschaft


A digital pulse processing device is capable of selecting desired precision. The digital pulse processing device includes a counter group for counting pulses output from a pulse output device, the counter group having a plurality of counters A and B that can be separated from and coupled with each other, a mode control circuit for instructing separation and coupling of the counters A and B, and a control circuit for separating and coupling the counters A and B in accordance with the instruction of the mode control circuit. An overflow condition of the free-run counter B is detected using an overflow flag. Detection of an overflow is conducted by setting the flag when an overflow condition has occurred twice or more. The flag is reset by rewriting the state of the flag by a software. An overflow condition which has occurred for the first time is detected in the conventional manner and is treated as carry or borrow. A register is provided to hold the value of the counter B when a microcomputer reads in the counter B. In this way, even when .DELTA.A(i)=0, speed detection operation can be executed using the value of the counter B obtained synchronously with the counting of the counter A.

1. Field of the Invention
The present invention relates to a digital pulse processing device suitable for use to preprocess a detection signal representing the speed of a moving or rotating body before it is supplied to a digital motor speed control device.
2. Description of the Related Art
The pulse processing function of conventional speed detection devices is disclosed in, for example, Japanese Patent Laid-open No. Sho59-100866. This pulse processing function of the speed detection device includes a first counter A for counting a pulse train output from a pulse generator, a second counter B for counting clock pulses having a fixed higher frequency than the pulse train, and a latch for storing the count of the second counter B. This speed detection device is implemented by hardware designed to store the counted value of the clock pulses of the second counter B each time a pulse is output from the pulse generator.
In the above-described speed detecting device, counting of the pulses from the pulse generator and counting of clock pulses are synchronized so as to achieve accurate speed detection. The speed detection operation carried out is to obtain a speed detection value Nt by executing the following expression using the pulse counted value A (i) of the first counter A, a latched value B (i) of the second counter B, the values A and B being obtained at the present reading in of a microcomputer, and the values A (i-1) and B (i-1) obtained by the previous reading in of the microcomputer: ##EQU1## where K is a constant, .DELTA.A is a change in the first counter A, and .DELTA.B is a change in the second counter B.
When the motor is rotating at a low speed, the pulse width of the pulses output from the pulse generator is large, and the counted value of the pulses may not change in the microcomputer's reading-in intervals which is generally several msec. At that time, .DELTA.A (i)=1, and .DELTA.B (i)=0, and the speed detection operation is impossible.
To overcome this problem, in the aforementioned conventional technique, a RD (read) signal is output from the microcomputer by the software. When the speed detecting device receives this RD signal, it forcibly stores the counted value of the clock pulses in the latch asynchronously with the counting of the pulse output device. In that case, the speed detection operation is executed using the previously obtained values of .DELTA.A (i) and .DELTA.B (i) obtained by subtracting the previously obtained clock pulses counted value from the clock pulses counted values latched by the RD signal.
Regarding a subsequent reading-in of the microcomputer, if no pulse is output from the pulse output device, .DELTA.A (i) is that used in the previous operation, and .DELTA.B (i) is the value obtained by adding to the previous .DELTA.B (i) the value obtained by subtracting the previously read in clock pulse counted value from the clock pulse counted value latched by the RD signal. Therefore, .DELTA.B (i) is the value obtained between the last pulse output from the pulse generator and the present reading-in presently read value of the microcomputer.
In the aforementioned conventional technique, when .DELTA.A (i)=0, the speed detection operation requires complicated processings, the such as branch processing, output of a RD signal and cumulative addition of .DELTA.B (i), which increase the burden on the software.
Furthermore, no consideration is given to the precision of the latch for storing the counted values A (i) and B (i) of the counter for counting the pulses of the pulse generator and the counter for counting the clock pulses. That is, since the number of bits for the latch is fixed, the precision is also fixed. Consequently, a higher precision than required is obtained for a certain application, while an insufficient precision is obtained for another application. As a result, the conventional latching is not versatile, and pulse processing cannot be achieved over a wide range of precision.
Furthermore, no consideration is given to the overflow of the counter B (i) for counting the clock pulses. That is, although .DELTA.B (i) can be obtained when an overflow condition occurs in the counter B (i) once, if an overflow condition occurs more than once, it is impossible to obtain an accurate .DELTA.B (i) because there is no function of checking the number of times the overflow condition occurs. This makes accurate speed detection impossible.


A luggage cart assembly includes a base that has a top side, a bottom side, a first end edge, a second end edge, a first lateral edge and a second lateral edge. A plurality of wheels is rotatably coupled to the bottom side. The top side has a plurality of wells extending therein. Each of the first and second side edges have two wells positioned adjacent thereto. A plurality of posts each has a first end and a second end and a bend positioned between the first and second ends. Each of the first ends is positionable into one of the wells such that second ends of adjacent posts extend toward each other. A pair of fastening members removably secures adjacent ones of the second ends together. A rod has a pair of opposite end. Each of the opposite ends is removably attached to one of the fastening members.

1. Field of the Invention
The present invention relates to cart devices and more particularly pertains to a new cart device for aiding a person in transporting their luggage from a vehicle and into a hotel or into their home.
2. Description of the Prior Art
The use of cart devices is known in the prior art. U.S. Pat. No. 5,090,725 describes a device for supporting garments in a vertical orientation. Another type of cart device is U.S. Pat. No. 2,793,764 which also describes a device adapted for supporting garments in a vertical orientation above a ground surface. Still yet another such device is found in U.S. Pat. No. 3,705,731.
While these devices fulfill their respective, particular objectives and requirements, the need remains for a device that allows a person to transport their own clothing and luggage from a vehicle and into a hotel room. This will save a person money as well as provide a method for transporting luggage when a bellhop is not available. Additionally, the device should be collapsible so that it is easily storable within a vehicle and may be stored within a dwelling when not in use. Further, the device may be used for transporting luggage into a dwelling and thereafter storing the luggage when the luggage is not being used.


An input device includes an input member to which a pressing operation is input, a base member on which the input member is mounted, an actuator disposed at least on an input member side and configured to vibrate the input member in a direction perpendicular to a pressing direction of the pressing operation, a braking member disposed to be in contact with the input member, a holding member disposed on a base member side and holding the braking member, and a position adjusting mechanism configured to adjust a position of at least one of the input member and the holding member with respect to the pressing direction.

As an example of an input device including a conventional touch screen, the input device described in Patent Document 1 has been known. The input device described in Patent Document 1 is configured to include a touch screen, an actuator, and a substantially U-shaped spring. The touch screen is for inputting an instruction by touching or pressing the operation surface. The actuator is for moving the touch screen relative to a reference object in at least one direction. The spring is configured to mechanically couple the reference object to the touch screen.