A reduced homography H for an optical apparatus to recover pose parameters from imaged space points Pi using an optical sensor. The electromagnetic radiation from the space points Pi is recorded on the optical sensor at measured image coordinates. A structural uncertainty introduced in the measured image points is determined and a reduced representation of the measured image points is selected based on the type of structural uncertainty. The reduced representation includes rays {circumflex over (r)}i defined in homogeneous coordinates and contained in a projective plane of the optical apparatus. At least one pose parameter of the optical apparatus is then estimated by applying the reduced homography H and by applying a condition on the motion of the optical apparatus, the condition being consonant with the reduced representation employed in the reduced homography H.

When an item moves without any constraints (freely) in a three-dimensional environment with respect to stationary objects, knowledge of the item's distance and inclination to one or more of such stationary objects can be used to derive a variety of the item's parameters of motion, as well as its complete pose. The latter includes the item's three position parameters, usually expressed by three coordinates (x, y, z), and its three orientation parameters, usually expressed by three angles (α, β, γ) in any suitably chosen rotation convention (e.g., Euler angles (ψ, θ, φ) or quaternions). Particularly useful stationary objects for pose recovery purposes include ground planes, fixed points, lines, reference surfaces and other known features.
Many mobile electronics items are now equipped with advanced optical apparatus such as on-board cameras with photo-sensors, including high-resolution CMOS arrays. These devices typically also possess significant on-board processing resources (e.g., CPUs and GPUs) as well as network connectivity (e.g., connection to the Internet, Cloud services and/or a link to a Local Area Network (LAN)). These resources enable many techniques from the fields of robotics and computer vision to be practiced with the optical apparatus on-board such virtually ubiquitous devices. Most importantly, vision algorithms for recovering the camera's extrinsic parameters, namely its position and orientation, also frequently referred to as its pose, can now be applied in many practical situations.
An on-board camera's extrinsic parameters in the three dimensional environment are typically recovered by viewing a sufficient number of non-collinear optical features belonging to the known stationary object or objects. In other words, the on-board camera first records on its photo-sensor (which may be a pixelated device or even a position sensing device (PSD) having one or just a few "pixels") the images of space points, space lines and space planes belonging to one or more of these known stationary objects. A computer vision algorithm to recover the camera's extrinsic parameters is then applied to the imaged features of the actual stationary object(s). The imaged features usually include points, lines and planes of the actual stationary object(s) that yield a good optical signal. In other words, the features are chosen such that their images exhibit a high degree of contrast and are easy to isolate in the image taken by the photo-sensor. Of course, the imaged features are recorded in a two-dimensional (2D) projective plane associated with the camera's photo-sensor, while the real or space features of the one or more stationary objects are found in the three-dimensional (3D) environment.
Certain 3D information is necessarily lost when projecting an image of actual 3D stationary objects onto the 2D image plane. The mapping between the 3D Euclidean space of the three-dimensional environment and the 2D projective plane of the camera is not one-to-one. Many assumptions of Euclidean geometry are lost during such mapping (sometimes also referred to as projectivity). Notably, lengths, angles and parallelism are not preserved. Euclidean geometry is therefore insufficient to describe the imaging process. Instead, projective geometry, and specifically perspective projection is deployed to recover the camera's pose from images collected by the photo-sensor residing in the camera's 2D image plane.
Fortunately, projective transformations do preserve certain properties. These properties include type (that is, points remain points and lines remain lines), incidence (that is, when a point lies on a line it remains on the line), as well as an invariant measure known as the cross ratio. For a review of projective geometry the reader is referred to H. X. M. Coexter, Projective Geometry, Toronto: University of Toronto, 2nd Edition, 1974; O. Faugeras, Three-Dimensional Computer Vision, Cambridge, Mass.: MIT Press, 1993; L. Guibas, "Lecture Notes for CSS4Sa: Computer Graphics—Mathematical Foundations", Stanford University, Autumn 1996; Q.-T. Luong and O. D. Faugeras, "Fundamental Matrix: Theory, algorithms and stability analysis", International Journal of Computer Vision, 17(1): 43-75, 1996; J. L. Mundy and A. Zisserman, Geometric Invariance in Computer Vision, Cambridge, Mass.: MIT Press, 1992 as well as Z. Zhang and G. Xu, Epipolar Geometry in Stereo, Motion and Object Recognition: A Unified Approach. Kluwer Academic Publishers, 1996.
At first, many practitioners deployed concepts from perspective geometry directly to pose recovery. In other words, they would compute vanishing points, horizon lines, cross ratios and apply Desargues theorem directly. Although mathematically simple on their face, in many practical situations such approaches end up in tedious trigonometric computations. Furthermore, experience teaches that such computations are not sufficiently compact and robust in practice. This is due to many real-life factors including, among other, limited computation resources, restricted bandwidth and various sources of noise.
Modern computer vision has thus turned to more computationally efficient and robust approaches to camera pose recovery. An excellent overall review of this subject is found in Kenichi Kanatani, Geometric Computation for Machine Vision, Clarendon Press, Oxford University Press, New York, 1993. A number of important foundational aspects of computational geometry relevant to pose recovery via machine vision are reviewed below to the benefit of those skilled in the art and in order to better contextualize the present invention.
To this end, we will now review several relevant concepts in reference to FIGS. 1-3. FIG. 1 shows a stable three-dimensional environment 10 that is embodied by a room with a wall 12 in this example. A stationary object 14, in this case a television, is mounted on wall 12. Television 14 has certain non-collinear optical features 16A, 16B, 16C and 16D that in this example are the corners of its screen 18. Corners 16A, 16B, 16C and 16D are used by a camera 20 for recovery of extrinsic parameters (up to complete pose recovery when given a sufficient number and type of non-collinear features). Note that the edges of screen 18 or even the entire screen 18 and/or anything displayed on it (i.e., its pixels) are suitable non-collinear optical features for these purposes. Of course, other stationary objects in room 10 besides television 14 can be used as well.
Camera 20 has an imaging lens 22 and a photo-sensor 24 with a number of photosensitive pixels 26 arranged in an array. A common choice for photo-sensor 24 in today's consumer electronics devices are CMOS arrays, although other technologies can also be used depending on application (e.g., CCD, PIN photodiode, position sensing device (PSD) or still other photo-sensing technology). Imaging lens 22 has a viewpoint O and a certain focal length f. Viewpoint O lies on an optical axis OA. Photo-sensor 24 is situated in an image plane at focal length f behind viewpoint O along optical axis OA.
Camera 20 typically works with electromagnetic (EM) radiation 30 that is in the optical or infrared (IR) wavelength range (note that deeper sensor wells are required in cameras working with IR and far-IR wavelengths). Radiation 30 emanates or is reflected (e.g., reflected ambient EM radiation) from non-collinear optical features such as screen corners 16A, 16B, 16C and 16D. Lens 22 images EM radiation 30 on photo-sensor 24. Imaged points or corner images 16A′, 16B′, 16C′, 16D′ thus imaged on photo-sensor 24 by lens 22 are usually inverted when using a simple refractive lens. Meanwhile, certain more compound lens designs, including designs with refractive and reflective elements (catadioptrics) can yield non-inverted images.
A projective plane 28 conventionally used in computational geometry is located at focal length f away from viewpoint O along optical axis OA but in front of viewpoint O rather than behind it. Note that a virtual image of corners 16A, 16B, 16C and 16D is also present in projective plane 28 through which the rays of electromagnetic radiation 30 pass. Because any rays in projective plane 28 have not yet passed through lens 22, the points representing corners 16A, 16B, 16C and 16D are not inverted. The methods of modern machine vision are normally applied to points in projective plane 28, while taking into account the properties of lens 22.
An ideal lens is a pinhole and the most basic approaches of machine vision make that an assumption. Practical lens 22, however, introduces distortions and aberrations (including barrel distortion, pincushion distortion, spherical aberration, coma, astigmatism, chromatic aberration, etc.). Such distortions and aberrations, as well as methods for their correction or removal are understood by those skilled in the art.
In the simple case shown in FIG. 1, image inversion between projective plane 28 and image plane on the surface of photo-sensor 24 is rectified by a corresponding matrix (e.g., a reflection and/or rotation matrix). Furthermore, any offset between a center CC of camera 20 where optical axis OA passes through the image plane on the surface of photo-sensor 24 and the origin of the 2D array of pixels 26, which is usually parameterized by orthogonal sensor axes (Xs, Ys), involves a shift.
Persons skilled in the art are familiar with camera calibration techniques. These include finding offsets, computing the effective focal length feff (or the related parameter k) and ascertaining distortion parameters (usually denoted by α's). Collectively, these parameters are called intrinsic and they can be calibrated in accordance with any suitable method. For teachings on camera calibration the reader is referred to the textbook entitled "Multiple View Geometry in Computer Vision" (Second Edition) by R. Hartley and Andrew Zisserman. Another useful reference is provided by Robert Haralick, "Using Perspective Transformations in Scene Analysis", Computer Graphics and Image Processing 13, pp. 191-221 (1980). For still further information the reader is referred to Carlo Tomasi and John Zhang, "How to Rotate a Camera", Computer Science Department Publication, Stanford University and Berthold K. P. Horn, "Tsai's Camera Calibration Method Revisited", which are herein incorporated by reference.
Additionally, image processing is required to discover corner images 16A′, 16B′, 16C′, 16D′ on sensor 24 of camera 20. Briefly, image processing includes image filtering, smoothing, segmentation and feature extraction (e.g., edge/line or corner detection). Corresponding steps are usually performed by segmentation and the application of mask filters such as Guassian/Laplacian/Laplacian-of-Gaussian (LoG)/Marr and/or other convolutions with suitable kernels to achieve desired effects (averaging, sharpening, blurring, etc.). Most common feature extraction image processing libraries include Canny edge detectors as well as Hough/Radon transforms and many others. Once again, all the relevant techniques are well known to those skilled in the art. A good review of image processing is afforded by "Digital Image Processing", Rafael C. Gonzalez and Richard E. Woods, Prentice Hall, 3rd Edition, Aug. 31, 2007; "Computer Vision: Algorithms and Applications", Richard Szeliski, Springer, Edition 2011, Nov. 24, 2010; Tinne Tuytelaars and Krystian Mikolajczyk, "Local Invariant Feature Detectors: A Survey", Journal of Foundations and Trends in Computer Graphics and Vision, Vol. 3, Issue 3, January 2008, pp. 177-280. Furthermore, a person skilled in the art will find all the required modules in standard image processing libraries such as OpenCV (Open Source Computer Vision), a library of programming functions for real time computer vision. For more information on OpenCV the reader is referred to G. R. Bradski and A. Kaehler, "Learning OpenCV: Computer Vision with the OpenCV Library", O'Reilly, 2008.
In FIG. 1 camera 20 is shown in a canonical pose. World coordinate axes (Xw,Yw,Zw) define the stable 3D environment with the aid of stationary object 14 (the television) and more precisely its screen 18. World coordinates are right-handed with their origin in the middle of screen 18 and Zw-axis pointing away from camera 20. Meanwhile, projective plane 28 is parameterized by camera coordinates with axes (Xc,Yc,Zc). Camera coordinates are also right-handed with their origin at viewpoint O. In the canonical pose Zc-axis extends along optical axis OA away from the image plane found on the surface of image sensor 24. Note that camera Zc-axis intersects projective plane 28 at a distance equal to focal length f away from viewpoint O at point o′, which is the center (origin) of projective plane 28. In the canonical pose, the axes of camera coordinates and world coordinates are thus aligned. Hence, optical axis OA that always extends along the camera Zc-axis is also along the world Zw-axis and intersects screen 18 of television 14 at its center (which is also the origin of world coordinates). In the application shown in FIG. 1, a marker or pointer 32 is positioned at the intersection of optical axis OA of camera 20 and screen 18.
In the canonical pose, the rectangle defined by space points representing screen corners 16A, 16B, 16C and 16D maps to an inverted rectangle of corner images 16A′, 16B′, 16C′, 16D′ in the image plane on the surface of image sensor 24. Also, space points defined by screen corners 16A, 16B, 16C and 16D map to a non-inverted rectangle in projective plane 28. Therefore, in the canonical pose, the only apparent transformation performed by lens 22 of camera 20 is a scaling (de-magnification) of the image with respect to the actual object. Of course, mostly correctable distortions and aberrations are also present in the case of practical lens 22, as remarked above.
Recovery of poses (positions and orientations) assumed by camera 20 in environment 10 from a sequence of corresponding projections of space points representing screen corners 16A, 16B, 16C and 16D is possible because the absolute geometry of television 14 and in particular of its screen 18 and possibly other 3D structures providing optical features in environment 10 are known and can be used as reference. In other words, after calibrating lens 22 and observing the image of screen corners 16A, 16B, 16C, 16D and any other optical features from the canonical pose, the challenge of recovering parameters of absolute pose of camera 20 in three-dimensional environment 10 is solvable. Still more precisely put, as camera 20 changes its position and orientation and its viewpoint O travels along a trajectory 34 (a.k.a. extrinsic parameters) in world coordinates parameterized by axes (Xw,Yw,Zw), only the knowledge of corner images 16A′, 16B′, 16C′, 16D′ in camera coordinates parameterized by axes (Xc,Yc,Zc) can be used to recover the changes in pose or extrinsic parameters of camera 20. This exciting problem in computer and robotic vision has been explored for decades.
Referring to FIG. 2, we now review a typical prior art approach to camera pose recovery in world coordinates (a.k.a. absolute pose, since world coordinates defined by television 14 sitting in room 10 are presumed stable for the purposes of this task). In this example, camera 20 is mounted on-board item 36, which is a mobile device and more specifically a tablet computer with a display screen 38. The individual parts of camera 20 are not shown explicitly in FIG. 2, but non-inverted image 18′ of screen 18 as found in projective plane 28 is illustrated on display screen 38 of tablet computer 36 to aid in the explanation. The practitioner is cautioned here, that although the same reference numbers refer to image points in the image plane on sensor 24 (see FIG. 1) and in projective plane 28 to limit notational complexity, a coordinate transformation exists between image points in the actual image plane and projective plane 28. As remarked above, this transformation typically involves a reflection/rotation matrix and an offset between camera center CC and the actual center of sensor 24 discovered during the camera calibration procedure (also see FIG. 1).
A prior location of camera viewpoint O along trajectory 34 and an orientation of camera 20 at time t=t−i are indicated by camera coordinates using camera axes (Xc,Yc,Zc) whose origin coincides with viewpoint O. Clearly, at time t=t−i camera 20 on-board tablet 36 is not in the canonical pose. The canonical pose, as shown in FIG. 1, obtains at time t=to. Given unconstrained motion of viewpoint O along trajectory 34 and including rotations in three-dimensional environment 10, all extrinsic parameters of camera 20 and correspondingly the position and orientation (pose) of tablet 36 change between time t=t−i and t=to. Still differently put, all six degrees of freedom (6 DOFs or the three translational and the three rotational degrees of freedom inherently available to rigid bodies in three-dimensional environment 10) change along trajectory 34.
Now, at time t=t1 tablet 36 has moved further along trajectory 34 from its canonical pose at time t=to to an unknown pose where camera 20 records corner images 16A′, 16B′, 16C′, 16D′ at the locations displayed on screen 38 in projective plane 28. Of course, camera 20 actually records corner images 16A′, 16B′, 16C′, 16D′ with pixels 26 of its sensor 24 located in the image plane defined by lens 22 (see FIG. 1). As indicated above, a known transformation exists (based on camera calibration of intrinsic parameters, as mentioned above) between the image plane of sensor 24 and projective plane 28 that is being shown in FIG. 2.
In the unknown camera pose at time t=t1 a television image 14′ and, more precisely screen image 18′ based on corner images 16A′, 16B′, 16C′, 16D′ exhibits a certain perspective distortion. By comparing this perspective distortion of the image at time t=t1 to the image obtained in the canonical pose (at time t=to or during camera calibration procedure) one finds the extrinsic parameters of camera 20 and, by extension, the pose of tablet 36. By performing this operation with a sufficient frequency, the entire rigid body motion of tablet 36 along trajectory 34 of viewpoint O can be digitized.
The corresponding computation is traditionally performed in projective plane 28 by using homogeneous coordinates and the rules of perspective projection as taught in the references cited above. For a representative prior art approach to pose recovery with respect to rectangles, such as presented by screen 18 and its corners 16A, 16B, 16C and 16D the reader is referred to T. N. Tan et al., "Recovery of Intrinsic and Extrinsic Camera Parameters Using Perspective Views of Rectangles", Dept. of Computer Science, The University of Reading, Berkshire RG6 6AY, UK, 1996, pp. 177-186 and the references cited by that paper. Before proceeding, it should be stressed that although in the example chosen we are looking at rectangular screen 18 that can be analyzed by defining vanishing points and/or angle constraints on corners formed by its edges, pose recovery does not need to be based on corners of rectangles or structures that have parallel and orthogonal edges. In fact, the use of vanishing points is just the elementary way to recover pose. There are more robust and practical prior art methods that can be deployed in the presence of noise and when tracking more than four reference features (sometimes also referred to as fiducials) that do not need to form a rectangle or even a planar shape in real space. Indeed, the general approach applies to any set of fiducials defining an arbitrary 3D shape, as long as that shape is known.
For ease of explanation, however, FIG. 3 highlights the main steps of an elementary prior art approach to the recovery of extrinsic parameters of camera 20 based on the rectangle defined by screen 18 in world coordinates parameterizing room 10 (also see FIG. 2). Recovery is performed with respect to the canonical pose shown in FIG. 1. The solution is a rotation expressed by a rotation matrix R and a translation expressed by a translation vector h, or {R, h}. In other words, the application of inverse rotation matrix R−1 and subtraction of translation vector h return camera 20 from the unknown recovered pose to its canonical pose. The canonical pose at t=to is marked and the unknown pose at t=t1 is to be recovered from image 18′ found in projective plane 28 (see FIG. 2), as shown on display screen 38. In solving the problem we need to find vectors pA, pB, pC and pD from viewpoint O to space points 16A, 16B, 16C and 16D through corner images 16A′, 16B′, 16C′ and 16D′. Then, information contained in computed conjugate vanishing points 40A, 40B can be used for the recovery. In cases where the projection is almost orthographic (little or no perspective distortion in screen image 18′) and vanishing points 40A, 40B become unreliable, angle constraints demanding that the angles between adjoining edges of candidate recovered screen 18 be 90° can be used, as taught by T. N. Tan et al., op. cit.
FIG. 3 shows that without explicit information about the size of screen 18, the length of one of its edges (or other scale information) only relative lengths of vectors pA, pB, pC and pD can be found. In other words, when vectors pA, pB, pC and pD are expressed by corresponding unit vectors {circumflex over (n)}A, {circumflex over (n)}B, {circumflex over (n)}C, {circumflex over (n)}D times scale constants λA, λB, λC, λD such that pA={circumflex over (n)}AλA, pB={circumflex over (n)}BλB, pC={circumflex over (n)}CλC and pD={circumflex over (n)}DλD, then only relative values of scale constants λA, λB, λC, λD can be obtained. This is clear from looking at a small dashed candidate for screen 18* with corner points 16A*, 16B*, 16C*, 16D*. These present the correct shape for screen 18* and lie along vectors pA, pB, pC and pD, but they are not the correctly scaled solution.
Also, if space points 16A, 16B, 16C and 16D are not identified with image points 16A′, 16B′, 16C′ and 16D′ then the in-plane orientation of screen 18 cannot be determined. This labeling or correspondence problem is clear from examining a candidate for recovered screen 18*. Its recovered corner points 16A*, 16B*, 16C* and 16D* do not correspond to the correct ones of actual screen 18 that we want to find. The correspondence problem can be solved by providing information that uniquely identifies at least some of points 16A, 16B, 16C and 16D. Alternatively, additional space points that provide more optical features at known locations in room 10 can be used to break the symmetry of the problem. Otherwise, the space points can be encoded by any suitable methods and/or means. Of course, space points that present intrinsically asymmetric space patterns could be used as well.
Another problem is illustrated by candidate for recovered screen 18**, where candidate points 16A**, 16B**, 16C**, 16D** do lie along vectors pA, pB, pC and pD but are not coplanar. This structural defect is typically resolved by realizing from algebraic geometry that dot products of vectors that are used to represent the edges of candidate screen 18** not only need to be zero (to ensure orthogonal corners) but also that the triple product of these vectors needs to be zero. That is true, since the triple product of the edge vectors is zero for a rectangle. Still another way to remove the structural defect involves the use of cross ratios.
In addition to the above problems, there is noise. Thus, the practical challenge is not only in finding the right candidate based on structural constraints, but also distinguishing between possible candidates and choosing the best one in the presence of noise. In other words, the real-life problem of pose recovery is a problem of finding the best estimate for the transformation encoded by {R, h} from the available measurements. To tackle this problem, it is customary to work with the homography or collineation matrix A that expresses {R, h}. In this form, the well-known methods of linear algebra can be brought to bear on the problem of estimating A. Once again, the reader should remember that these tools can be applied for any set of optical features (fiducials) and not just rectangles as formed by screen 18 used for explanatory purposes in this case. In fact, any set of fiducials defining any 3D shape in room 10 can be used, as long as that 3D shape is known. Additionally, such 3D shape should have a geometry that produces a sufficiently large image from all vantage points (see definition of convex hull).
FIGS. 4A & 4B illustrate realistic situations in which estimates of collineation matrices A are computed in the presence of noise for our simple example. FIG. 4A shows on the left a full field of view 42 (F.O.V.) of lens 22 centered on camera center CC while camera 20 is in the canonical pose (also see FIG. 1). Field of view 42 is parameterized by sensor coordinates of photo-sensor 24 using sensor axes (Xs,Ys) Note that pixelated sensors like sensor 24 usually take the origin of array of pixels 26 to be in the upper corner. Also note that camera center CC has an offset (xsc,ysc) from the origin. In fact, (xsc,ysc) is the location of viewpoint O and origin o′ of projective plane 28 in sensor coordinates (previously shown in camera coordinates (Xc,Yc,Zc)—see FIG. 1). Working in sensor coordinates is initially convenient because screen image 18′ is first recorded along with noise by pixels 26 of sensor 24 in the image plane that is parameterized by sensor coordinates. Note the inversion of real screen image 18′ on sensor 24 in comparison to virtual screen image 18′ in projective plane 28 (again see FIG. 1).
On the right, FIG. 4A illustrates screen image 18′ after viewpoint O has moved along trajectory 34 and camera 20 assumed a pose corresponding to an unknown collineation A1 with respect to the canonical pose shown on the left. Collineation A1 consists of an unknown rotation and an unknown translation {R, h}. Due to noise, there are a number of measured image points {circumflex over (p)}i=({circumflex over (x)}i,ŷi), indicated by crosses, for corner images 16A′, 16B′, 16C′ and 16D′. (Here the "hat" denotes measured values not unit vectors.) The best estimate of collineation A1, referred to as Θ (estimation matrix), yields the best estimate of the locations of corner images 16A′, 16B′, 16C′ and 16D′ in the image plane. The value of estimation matrix Θ is usually found by minimizing a performance criterion through mathematical optimization. Suitable methods include the application of least squares, weighted average or other suitable techniques to process measured image points {circumflex over (p)}i=({circumflex over (x)}i,ŷi). Note that many prior art methods also include outlier rejection of certain measured image points {circumflex over (p)}i=({circumflex over (x)}i,ŷi) that could "skew" the average. Various voting algorithms including RANSAC can be deployed to solve the outlier problem prior to averaging.
FIG. 4B shows screen image 18′ as recorded in another pose of camera 20. This one corresponds to a different collineation A2 with respect to the canonical pose. Notice that the composition of collineations behaves as follows: collineation A1 followed by collineation A2 is equivalent to composition A1A2. Once again, measured image points {circumflex over (p)}i=({circumflex over (x)}i,ŷi) for the estimate computation are indicated.
The distribution of measured image points {circumflex over (p)}i=({circumflex over (x)}i,ŷi) normally obeys a standard noise statistic dictated by environmental conditions. When using high-quality camera 20, that distribution is thermalized based mostly on the illumination conditions in room 10, the brightness of screen 18 and edge/corner contrast (see FIG. 2). This is indicated in FIG. 4B by a dashed outline indicating a normal error region or typical deviation 44 that contains most possible measured image points {circumflex over (p)}i=({circumflex over (x)}i,ŷi) excluding outliers. An example outlier 46 is indicated well outside typical deviation 44.
In some situations, however, the distribution of points {circumflex over (p)}i=({circumflex over (x)}i,ŷi) does not fall within typical error region 44 accompanied by a few outliers 46. In fact, some cameras introduce persistent or even inherent structural uncertainty into the distribution of points {circumflex over (p)}i=({circumflex over (x)}i,ŷi) found in the image plane on top of typical deviation 44 and outliers 46.
One typical example of such a situation occurs when the optical system of a camera introduces multiple reflections of bright light sources (which are prime candidates for space points to track) onto the sensor. This may be due to the many optical surfaces that are typically used in the imaging lenses of camera systems. In many cases, these multiple reflections can cause a number of ghost images along radial lines extending from the center of the sensor or camera center CC as shown in FIG. 1 to the point where the optical axis OA of the lens intersects with the sensor. This condition results in a large inaccuracy when using the image to measure the radial distance of the primary image of a light source. The prior art teaches no suitable formulation of the homography or collineation to nonetheless recover parameters of camera pose under such conditions.

This patent is subject to a terminal disclaimer.

Reduced homography for recovery of pose parameters of an optical apparatus producing image data with structural uncertainty


Disclosed herein is a component architecture platform (CAP) framework that provides a mechanism to update firmware, drivers, and/or application software in an embedded system, such as in mobile electronic devices. The framework also facilitates access to generated update packages by the embedded system and provides updates to firmware, drivers, content or application software in a fault tolerant mode. Generation of update packages is more efficient and the update packages employing CAP are more compact than prior solutions. A distributed version of CAP, (DCAP), also provides access to functionality or components located at remote locations on other platforms.

Embedded systems (i.e., mobile electronic devices having embedded software/firmware), for example, mobile cellular phones, personal digital assistants (PDA's), pagers, MP3 players, digital cameras, etc. often contain firmware and/or application software that are either provided by the manufacturers of the electronic devices, telecommunication carriers, or third parties. Such electronic devices are typically called embedded systems because the firmware and application software that they contain are typically embedded in silicon memory, such as FLASH. However, firmware and/or application software often contain software bugs. New versions of the firmware and software are periodically released to fix the bugs, introduce new features, or both.
A fundamental problem in providing access to new releases of firmware and software is that the embedded systems (electronic devices) are often constrained in terms of resources, such as available memory. Attempts to upgrade firmware or software by end-users often results in making the device, or some features of the device inoperable. Additionally, when changes to a firmware component, such as a driver, need to be made, there is no easy way to swap the old one out and put in a new one. Typically, the device has to be reflashed by a new FLASH image that is created by recompiling all or most of the code and/or rebuilding the image file. It can be seen that there is a need for an architecture where such recompilation or rebuilding is either made unnecessary or minimized and simplified.
When a new version of a driver or a function is to be introduced into embedded systems, all references to the old driver or function that occur in all other software/firmware sections have to be changed. Similarly, when a data item is shifted around in the memory of an embedded device, all references to that particular data item need to be updated. These are two very important issues which must be faced by embedded system designers.
In current embedded system technology, for example in mobile electronic devices, firmware is simply one big mass making it very hard to manipulate or update individual functions or sections independently. It can be seen that there is a need for a next generation architecture that enables updates of independent components within cell phones and other embedded systems.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings appended hereto.

Embedded system employing component architecture platform

Hewlett-Packard Development Company, L.P.


An improved method and apparatus for winding wire onto toroidal cores in which the wire is fed into a circular channel to form a coil that passes through the core repeatedly. The wire is fed to the apparatus by a cylindrical capstan for creating tension to straighten the wire. The wire is circulated in the channel by pairs of synchronously driven rollers, with one roller pair gripping the wire more loosely to permit slippage. The channel has a narrowed width adjacent to the rollers to control wire deflection. A movable feed track exit allows smooth feeding of wire into the channel, while permitting increased capacity by sliding the exit inward of the growing coil. A variable transmission adjusts the rate at which the wire is fed into the channel relative to the rate at which it circulates. A split block wire cutter is adjustable to compensate for cutter wear.

The method and apparatus disclosed herein are essentially an improvement to the method and apparatus for winding ring-shaped articles disclosed in U.S. Pat. Nos. 3,732,901 and 3,985,310 to Kent, et al, which are incorporated herein by reference.
These patents disclose a method and an apparatus for winding wire strands onto toroidal cores. The apparatus includes a feed mechanism that draws a length of wire from a source spool and feeds it through a feed tube into a radially inwardly facing circular channel. Two pairs of compliant circulating rollers are positioned on opposite sides of the channel to grip the wire and advance it to form a first loop. After the first loop is formed, the leading end of the wire continues to hug the channel's radial boundary as subsequent loops are accumulated inside the first loop during wire feeding.
In the Kent apparatus, a gap is provided in the radial boundary of the channel for receiving a toroidal core, with the core's central aperture aligned with the gap so that the circulating wire passes through the aperture. The upper and lower boundaries of the channel are closely spaced to maintain the loops in a single flat concentric layer as the loops accumulate and are circulated. When sufficient wire has been fed, the feeding is stopped, but the circulation of the loops continues, tightly winding a turn of wire onto the core for each complete circulation of the loops in the channel. Two or more wires can be wound onto a core at the same time with the prior patented Kent apparatus.
Although effective, the Kent apparatus has limited reliability when pushed beyond its useful capacity. It is a complex machine of small scale for manufacturing miniature electronic components; it must operate at a high speed to provide cost-effective manufacturing; the fine wire used is highly susceptible to jamming and buckling, which disable the machine until a skilled technician can correct the problem. These reliability problems prevent the existing machine from being used for manufacturing cores having a large number of wire turns. The existing machine has a circulating channel diameter of 21/2 inches, with a capacity of three feet of wire. When greater lengths are loaded, the wire typically jams in the circulating chamber, which can only reliably contain about five loops of wire. This prevents the prior apparatus from being used to manufacture the many wire wound core products of larger size that are currently manufactured by other methods.
An analysis of this problem has revealed that these functional limitations of the prior art apparatus arise from a number of different structural limitations:
A first limitation of the prior art apparatus is that slightly damaged or dented wire may cause a jam in the machine. If a dent occurs in the leading portion of the wire, it is particularly likely to snag or catch in the machine to cause a jam. The prior art feeding mechanism uses a frictional driven roller to draw the wire from a source spool. The driven roller does not provide sufficient tension to draw the wire through a conventional wire straightener to eliminate kinks. The lack of a wire straightener also prevents the use of wire source spools having a smaller diameter than the circulating channel, because the natural curvature of the wire would cause the leading end of the wire to bend inward from the radial boundary of the channel rather than to hug the wall, as is required for successful operation of the machine.
A second limitation of the prior art apparatus is that each circulating roller pair consists of a driven roller and an idler. This results in an imbalanced driving force acting on the wire, which permits inconsistent and unpredictable slippage between the rollers and the wire. Consequently, the wire loops tend to be deflected out of a flat circular path, causing jamming.
A third limitation of the prior art apparatus is that the circulated wire loops are not advanced at precisely the same rate by the opposite pairs of circulating rollers. This can cause the wire to buckle or bunch between the rollers on one side of the channel and to be pulled excessively tight on the other side of the channel. Furthermore, even if the opposite pairs are turned at precisely the same rate, the conical rubber rollers have slightly unpredictable properties which cause errors to accumulate, especially as the number of wire loops in the channel increases.
A fourth limitation of the prior art apparatus is found in a portion of the circulating channel adjacent to the circulating rollers. The upper and lower boundaries of the channel are spaced apart by a width sufficient to permit the wire loops to circulate without excessive resistance. However, this width can be too wide to restrict unwanted deflection of the wire at the circulating rollers. As the leading end of the wire exits a circulating roller pair, there is a tendency for the adjacent loops to attempt to ride over one another, causing the wire to jam. This is increasingly a problem as loops accumulate, and particularly when the leading end of the wire passes through the circulating roller and must push the adjacent inner loops inwardly. Narrowing the channel width to solve this problem only creates a friction problem that impairs circulation of the wire loops.
A fifth limitation of the prior art apparatus is that the feed tube exit is fixed at a position adjacent to the circulating channel radial boundary, which prevents a large number of wire loops from being accumulated in the chamber. The position is a compromise between larger capacity and reliable entry of the wire. The feed tube exit must be positioned sufficiently close to the channel boundary to permit the wire smoothly to contact the radial boundary in a nearly tangential relationship to avoid entry jams. However, this prevents the width of the accumulated bundle of wire loops from exceeding the distance between the tube exit and the channel radial boundary, because the tube exit must remain inward of the innermost loop for feeding to continue.
A sixth limitation of the prior art apparatus is that the wire cutter, which cuts the wire after each core is wound, requires frequent and expensive replacement. The cutter is a cylindrical shear that is sized to fit closely within a cylindrical cutter block bore. As the cutter wears, the fit loosens. Consequently, a dull cutter creates a burr on the leading end of the wire segment instead of cutting it cleanly. Such a burr is likely to catch on a surface of the channel and cause a wire jam. As this problem develops, the cutter must be replaced.

Method and apparatus for winding ring-shaped articles


A subsampling receiver (50, 50′, 50″) for converting an RF signal to baseband is disclosed. The subsampling receiver (50, 50′, 50″) may be implemented into a wireless communications device (40), such as a wireless telephone handset. In one disclosed embodiment, the receiver (50) includes a sample and hold circuit (80) that samples a bandpass filtered input modulated signal at the subsampling frequency (fs) that is well below the RF carrier frequency but twice the bandwidth (BW) of the payload; the sampled signal is digitized, and applied to two digital mixers (85I, 85Q) to produce in-phase and quadrature components (I,Q) of the payload. In another embodiment, the receiver (50′) includes two sample and hold circuits (96I, 96Q) to sample the filtered signal at different phases of the sampling frequency, to produce the in-phase and quadrature digital components. In a third embodiment, the receiver (50″) includes an analog mixer (116) to downconvert the RF input to an intermediate frequency, prior to digitization and digital mixing at quadrature phase.

This invention is in the field of wireless communications, and is more specifically directed to receiver circuitry used in such communications.
The popularity of mobile wireless communications has increased dramatically over recent years. It is expected that this technology will become even more popular in the foreseeable future, both in modern urban settings, and also in rural or developing regions that are not well served by line-based telephone systems. This increasing wireless traffic strains the available communications bandwidth for a given level of system infrastructure. As a result, there is substantial interest in increasing bandwidth utilization of wireless communications system to handle this growth in traffic.
This trend toward heavier usage of wireless technologies for communications, in combination with the advent of so-called third-generation, or "3G", wireless communications that also carry data, video, and other high data rate payloads, will require continuing improvements in the processing capabilities of the communications equipment. In particular, the higher required data rates will require corresponding increases in the digital processing of the communications payloads.
Modern digital communications technology utilizes multiple-access techniques to increase bandwidth utilization, and thus to carry more wireless traffic. Under current approaches, both time division multiple access (TDMA) and code division multiple access (CDMA) techniques are used in the art to enable the simultaneous operation of multiple communication sessions, or wireless "connections", each involving voice communications, data communications, or any type of digital payload. As evident from the name, TDMA communications are performed by the assignment of time slots to each of multiple communications, with each conversation transmitted alternately over short time periods. CDMA technology, on the other hand, permits multiple communication sessions to be transmitted simultaneously in both time and frequency, by modulating the signal with a specified code. On receipt, application of the code will recover the corresponding conversation, to the exclusion of the other simultaneously received conversations.
Wideband CDMA (WCDMA) is an extension of CDMA communications, and is contemplated to be useful for enhanced services such as contemplated in 3G wireless. WCDMA involves a higher chip rate than in conventional CDMA, and thereby supports higher bit rates, increases spectrum efficiency by way of better statistical averaging, and provides better coverage by improving frequency diversity.
In the receipt of wireless communications devices, digital receiver circuitry in general performs the function of converting the received high frequency signal to a "baseband" signal output. As known in the art, the term "baseband" refers to the signal at its original band of frequencies. The baseband signal is typically in its multiplexed form, for example corresponding to multiple communications that are carried out on multiple time or code channels, depending upon whether the communications are TDMA, CDMA, or WCDMA.
Modern wireless systems place stringent demands on the analog filtering and digital processing of received signals. These demands arise from the high frequencies involved in conventional wireless communications, such frequencies typically in the radio frequency (RF) bands, and also from the relatively low received signal power levels. As a result, relatively costly and complex techniques are commonplace in these systems.
For example, surface acoustic wave (SAW) filters are often used in conventional wireless receivers, for example in implementing band pass filters. As known in the art, conventional SAW filters include a piezoelectric substrate, on the surface of which input and output sets of interdigitated metal fingers are formed. The bandpass filtering is effected by the received signal being applied to the input set of interdigitated metal fingers, with surface acoustic waves excited by the piezoelectric substrate in response to the electric field generated between the electrodes. These acoustic waves propagate along the surface of the substrate and are received at the output set of interdigitated fingers, at which the piezoelectric substrate produces electrical signals in response to the surface acoustic waves. The wavelength of the output signals are determined by the lengths of the output fingers. Conventional SAW devices readily attain high frequency performance (with Q values up to on the order of 1000) while remaining relatively compact, in comparison with an equivalent electrical filter. However, because of the piezoelectric substrate, SAW filters are not integratable with conventional semiconductor integrated circuits. Accordingly, the use of SAW filters adds significantly to system cost.
Various conventional receiver architectures are now used in modern wireless systems, such as base stations and wireless handsets. These classes of architectures include heterodyne receivers, direct conversion receivers, and digital mixer architectures. FIG. 1 illustrates a first example of conventional heterodyne receiver 10. Receiver 10 includes SAW bandpass filter 2, which receives input RF signal RFI, and passes its filtered output to low noise amplifier (LNA) 4. The amplified signal is then downconverted by first mixer 6, which is typically an active mixer (gain>unity) that generates an output signal at an intermediate frequency that is the difference between the amplified RF input signal RFI and local oscillator signal LO1. This downconverted signal is then filtered by second SAW bandpass filter 8, and applied to automatic gain control (AGC) 12. The filtered downconverted signal at the intermediate frequency is then downconverted to baseband by I-Q mixers 14, which again are greater-than-unity gain analog mixers applying a periodic signal from a second local oscillator (not shown). The downconverted baseband signal is filtered by analog low-pass filter 16. Analog-to-digital converter (ADC) 18 samples and converts the baseband signal, at a sampling frequency that satisfies the Nyquist criterion of twice the bandwidth of the communicated signal. The digital signal is then decimated by decimating filter 19 to reduce the data rate, following which the signal is ready for demodulation and decoding.
However, this conventional heterodyne architecture is quite costly to implement, and also consumes a great deal of power, which is problematic for battery-powered devices such as wireless telephone handsets. A primary reason for this high power consumption and high cost derives from the use of SAW filters 2, 8, which necessarily consume significant power and must be realized off-chip, as described above. Because analog mixers 6, 8 operate at relatively low chopping frequencies, with greater than unity gain, high-Q filters such as SAW filters are required for reasonable fidelity. The multiple downconversions necessary to bring the input signal to baseband exacerbate these issues.
Another type of conventional receiver reduces these noise issues by using only a single mixer to directly downconvert the RF signal to baseband. FIG. 2 illustrates an example of this type of architecture, in the form of conventional direct conversion receiver 20. In this example, SAW filter 22 receives input signal RFI, and applies the bandpass filtered signal to LNA 24. I-Q stage mixer 26 downconverts this filtered amplified input signal to baseband. Low pass filter 28 and AGC 29 clean up this downconverted signal, prior to digitization by ADC 31 and decimating by decimating filter 33, similarly as described above. While this architecture reduces the cost of manufacture relative to the heterodyne architecture of FIG. 1, the use of only one level mixer for downconversion causes this architecture to suffer from DC offset problems, significant even-order distortion, and flicker noise.
FIG. 3 illustrates a conventional receiver architecture of the low-IF digital mixer type, which is effectively a compromise between the heterodyne and direct conversion receivers of FIGS. 1 and 2. As shown in FIG. 3, receiver 30 receives the RF input signal RFI with SAW bandpass filter 32, and applies the filtered output to LNA 34 as before. A single mixer 36 downconverts the filtered input signal to an intermediate frequency, which is again filtered by second SAW filter 38, and adjusted by AGC 39. ADC 41 converts the signal to digital, at a sampling frequency that is four times the intermediate frequency to which mixer 36 downconverted the input signal. I-Q mixer 45 then downconverts the digital signal, by applying a pattern of {−1, 0, +1, 0, 1, . . . }, at the sampling frequency, to the digital samples from ADC 43. This digital mixing by mixer 45 effectively applies a sinusoid of one-fourth of the sampling frequency to the digital output. Decimating filter 47 reduces the output data rate.
Digital mixer receiver 30 of FIG. 3 is a compromise of the heterodyne and direct conversion receivers, in that it still uses two stage mixers, but only one mixer is an analog mixer. The second, digital, mixer is not as sensitive to noise and distortion as an analog mixer, and thus receiver 30 is contemplated to provide good performance. In addition, the I & Q signals are generated in the digital domain, thus the matching between the I & Q branches is optimized. However, two SAW filters are still required in digital mixer receiver 30, maintaining relatively high cost for this approach.


Apparatus for securing freight in the form of a plurality of articles which are stacked on a floor to form a geometric solid, the solid having an upper edge, the apparatus being composed of: a frame which is composed of a roof and support members which support the roof above the floor; an edge protector assembly having at least one edge protector formed to rest against a portion of the upper edge of the geometric solid; a lifting mechanism including at least one cable via which the edge protector assembly is suspended from the roof, the lifting mechanism being operable for vertically displacing the edge protector assembly to lower the at least one edge protector into contact with the upper edge portion; and strap members for directly securing the at least one edge protector to the floor.

The present invention relates to the handling of freight, and particularly the securing of freight on a flatbed of a truck or trailer, or of any other vehicle such as a railroad car. Vehicles employed for transporting freight can be divided between closed bed and open bed vehicles. It is known that open bed vehicles, commonly known as flatbed vehicles, offer a number of advantages, including greater flexibility in accommodating a variety of loads and lower manufacturing costs. In addition, a flatbed vehicle offers access to the entire load, which can frequently constitute a significant advantage.
However, freight which is loaded on a flatbed vehicle must be reliably secured in place and the systems which have heretofore been proposed and used all require the expenditure of considerable physical effort and time to secure the freight to the bed before transport.
When freight is to be shipped on a flatbed vehicle, it is a general practice to stack the freight in the form of a geometric solid, usually having the form of a prism, and to then immobilize the geometric solid by passing fastening devices from one side of the flatbed, over the top of the solid, to the other side of the flatbed. The freight may be in the form of containers which are stacked to form a rectangular prism, after which the load is secured in place.
According to conventional practice, the load is secured in place by providing some type of edge protector, which may be constituted by wooden boards, and then placing straps, cables or ropes across the top of the load, from fastening points on one side of the bed to fastening points on the opposite side thereof. Such an arrangement is disclosed, for example, in U.S. Pat. No. 3,378,889, which issued on Apr. 23, 1968.
Use may be made of specially formed edge protectors having the form of right angle pieces, as disclosed in U.S. Pat. No. 5,584,623, which issued on Dec. 17, 1996.
In known systems, the operator must climb onto the flatbed in order to lift the edge protectors into position, or it may be necessary to utilize poles to lift the edge protectors into place. It frequently occurs that an edge protector falls off of the pole, or off of the load before it is secured in place, causing damage to the edge protector and possibly also injury to the operator.
After the edge protectors have been positioned, it is necessary to secure the edge protectors in place with straps, cables or ropes, which involves tossing the straps, etc., over the top of the load. When not in use, the straps must be rolled up for storage. All of these operations are physically demanding and can cause various types of repetitive motion injury.
In the system disclosed in U.S. Pat. No. 3,378,889, cited above, ropes must be fastened across the top of the load between edge protector assemblies and between each edge protector assembly and anchors along the sides of the bed. Thus, this system presents all of the above-mentioned difficulties associated with prior art systems.
In addition, it is usually necessary to cover the entire load with a tarpaulin, which generally weighs between 50 and 100 pounds and must be lifted to the top of the load by lifting equipment such as a forklift. Then, the tarpaulin must be unrolled to cover the top and sides of the load. There is a considerable risk of the tarpaulin falling during installation. In order to unload the flatbed, the tarpaulin must be pulled off of the load and then folded and stowed, all of which require strenuous repetitive motions that can cause a variety of injuries.

Assembly for securing articles to a moveable platform


A gas turbine engine turbine section includes at least one blade extending radially outwardly to an outer tip. A blade outer air seal assembly is positioned radially outwardly of the radially outer tip. The blade outer air seal has forward and aft hooks. The forward and aft hooks are supported on forward and aft seal hooks of an attachment block. The attachment block has a forward case mount hook and an aft case mount hook. The attachment block is supported on a forward case hook and an aft case hook of a static casing within the engine. The forward case mount hook and the aft case mount hook on the attachment block face in a common axial direction. The forward case hook and the aft case hook face in a common axial direction which is opposed to the common axial direction. A method is also disclosed.

This application relates to a structural support for supporting a blade outer air seal in a gas turbine engine.
Gas turbine engines are known and typically include a compressor compressing air and delivering it into a combustor. The air is mixed with fuel in the combustor and ignited. Products of the combustion pass downstream over turbine rotors, driving them to rotate.
It is desirable to ensure that the bulk of the products of combustion pass over turbine blades on the turbine rotor. As such, it is known to provide blade outer air seals radially outwardly of the blades.
Blade outer air seals raise challenge in effectively mounting their assemblies to the engines.

Structural support for blade outer air seal assembly


The inventor found that the lightwave of a semiconductor laser includes, in addition to the laser oscillation lightwave, a weak, continuous noise component having a different wavelength (here, referred to as natural emission lightwave). The inventor also found that in the wavelength division multiplexing communication optical system in which signal lightwaves having a plurality of wavelengths are combined to transmit over a single optical fiber so as to be separated at the other end to receive with a plurality of light-receiving devices, the natural emission lightwave causes crosstalk. A natural emission lightwave-blocking filter that reflects a natural emission lightwave is placed on the optical path between the semiconductor laser and the optical fiber. The natural emission lightwave-blocking filter blocks the natural emission lightwave, preventing the crosstalk.

1. Field of the Invention
The present invention relates to the improvement of an optical module to be used in unidirectional or bidirectional communication.
2. Description of the Background Art
In the optical communication, an optical signal is produced by a semiconductor laser (LD) at one node, the optical signal is sent through an optical fiber, and the optical signal is read out by a photodiode (PD) at another node. Transmission and reception of the signal is performed by using two optical fibers in one case and one optical fiber in another case. As the optical source, a semiconductor laser (LD), a light-emitting diode (LED), or the like is used. Here, it is assumed that an LD is used as the light source.
When it is intended to send the largest possible number of signals by using a single optical fiber, the wavelength division multiplexing transmission is employed. Two or more signal lightwaves Λ1, Λ2, . . . having different wavelengths are produced by different LDs at different nodes. The signal lightwaves are combined to send over a single optical fiber. The transmitted signals are separated at the exit according to the wavelengths. The separated signals are detected by different PDs at different nodes.
As a multiplexer for combining lightwaves having different wavelengths and as a demultiplexer for separating lightwaves having different wavelengths, a WDM (in this specification, the term WDM is used to mean a wavelength multiplexer or demultiplexer) and the like are used. When a signal is sent in one direction, a plurality of transmitting nodes are provided at one end of the optical fiber. The transmitting nodes are denoted as U1, U2, U3, . . . Um. At the other end, the same number of receiving nodes are provided. They are denoted as W1, W2, W3, . . . Wm. The light sources for all the transmitting nodes are semiconductor lasers LD1, LD2, LD3, . . . LDm having different oscillation wavelengths. The different oscillation wavelengths are denoted as Λ1, Λ2, Λ3, . . . Λm. The demultiplexer can completely separate the lightwaves Λ1, Λ2, Λ3, . . . Λm having different wavelengths. Therefore, it is supposed that no interference occurs between different nodes.
FIG. 19 shows a simplified optical communication system. For simplicity, in this system, m=2 is employed. However, the same phenomenon occurs in a general system in which m=m. The LD1 at the U1 generates a transmission lightwave of ΛA. The lightwave propagates through an optical fiber 38, a multiplexer (WDM) 39, an optical fiber 40, a demultiplexer (WDM) 42, and an optical fiber 43 to enter a PD1 at the receiving node W1. In this case, however, from the U2, although the magnitude is small, another lightwave of ΛA may enter the PD1 at the W1, causing a noise.
Similarly, the receiving node W2 receives the signal lightwave ΛB from the U2, together with a small magnitude of the lightwave ΛB from the U1. This small magnitude causes a noise. In other words, the W2 receives the signal lightwave from the U2 and a noise form the U1. This example has only two pairs. However, in the case where the system has "m" pairs and they transmit and receive signal lightwaves through a common optical fiber 40, all the nodes may have a possibility of receiving not only a single signal lightwave but also "m−1" noise lightwaves.
In the case where a central office and each of the terminal optical network units (ONUs) are connected with a single optical fiber and the system performs bidirectional communication by sending an analog signal and a digital signal, there also exists a possibility of interference. FIG. 20 shows schematically such a wavelength division multiplexing optical communication system. A central office has a node Ua for transmitting and receiving a digital signal and a node Ub for transmitting an analog signal. The node Ua is provided with a LDa for converting a digital signal into an optical signal of ΛA and a PDa for converting an optical signal of Λc into a digital signal. A digital signal from the Ua is sent as an optical signal of ΛA and travels through an optical fiber 48, a multiplexer (WDM) 49, and an optical fiber 50 to arrive at a PDc at the terminal Wc. The PDc receives the signal. An LDe at the terminal ONU generates a digital signal having a wavelength of Λc. The digital signal is transmitted to the PDa at the Ua in the central office through the optical fiber 50, the multiplexer (WDM) 49, and the optical fiber 48.
If this is only the operation, it is simply a one-to-one bidirectional communication. However, in addition to the above operation, the LDb in the Ub at the central office transmits an analog signal ΛB having a wavelength of ΛB. The analog signal travels through an optical fiber 54, the multiplexer (WDM) 49, and the optical fiber 50 to enter a PDd at the Wc. In such a case, the two lasers LDa and LDb in the central office have different oscillation wavelengths of ΛA and ΛB. This causes interference in the PDc and PDd. Even though the multiplexer (WDM) 49 operates normally, the interference occurs.
The present inventor has studied variously about the cause. Finally, the present inventor has determined the cause of the interference. A semiconductor laser is supposed to generate a stimulated emission lightwave having a single wavelength of Λ. Actually, however, in addition to that emission, a semiconductor laser also generates a weak lightwave. According to the theory of the lasing, in the case where a population inversion is produced by a current, when a stimulated emission occurs, all the excited electrons are supposed to return to the ground state simultaneously, generating an oscillation at the same phase and the same wavelength. It is explained that when the excitation energy exceeds a threshold value, all the energy is absorbed into a mode having a common phase and wavelength, producing only a lightwave having a single wavelength of Λ.
The actual fact is different, however. At the time the electrons return to the ground state, a lightwave is emitted that has an energy corresponding to the level difference between the conduction band and the valence band. In this case, the electrons in the conduction band also have kinetic energy, and the holes in the valence band also have kinetic energy. Therefore, even when the electron-hole pairs disappear due to the returning of the electrons from the conduction band to the valence band, a small difference in energy exists from pair to pair. This energy difference may produce a plurality of longitudinal modes. Even when only a single longitudinal mode exists, a lightwave, although weak, is produced that has a wavelength other than Λ.
In the case of a semiconductor laser, which has a cavity short in length and has a large gain, a lightwave having a wavelength other than the oscillation wavelength Λ still exists. So far, the existence of such a lightwave has not even been noticed. The present inventor has found that such a lightwave having a wavelength other than Λ is emitted from a semiconductor laser. Here, the thus emitted lightwave is referred to as a "natural emission lightwave."
The term "natural emission lightwave" is slightly different in meaning from the term "spontaneous emission lightwave" used in the laser theory. Originally, a laser is devised as a solid laser or a gas laser. In this case, the excitation level is distinct and the energy difference in the population-inverted level is determined uniquely. There exist no various energy levels. Therefore, the wavelength of the generated lightwave is determined as a single wavelength. Both the spontaneous emission lightwave and the laser oscillation lightwave have the same wavelength. When the spontaneous emission lightwaves become to have a uniform phase, they become to be the laser oscillation lightwaves. In other words, when the phase is uniform, they are the laser oscillation lightwaves. When the phase is randomly distributed, they are the spontaneous emission lightwaves. At least, both the spontaneous emission lightwave and the laser oscillation lightwave have the same wavelength (energy).
In the case of a semiconductor laser, however, the light emission is not produced by the two-level transition of atoms but by the current injection. Consequently, the light emission by the electron-hole pair produces different wavelengths. Here the term "natural emission lightwave" is used to have a wider meaning than the "spontaneous emission lightwave" used in the ordinary laser engineering. The term "natural emission lightwave" has a meaning different from the term "spontaneous emission lightwave" used in the ordinary laser engineering based on the explanation of the gas laser. Here, the emitted lightwaves having different energies (wavelengths), not different phases, are referred to as the "natural emission lightwave Σn." To emphasize that the natural emission lightwave includes a large number of wavelengths, the sign Σ is used.
FIG. 21 is a wavelength spectrum of a semiconductor laser emitting a lightwave at a wavelength of Λq (for example, 1,490 nm). The horizontal axis represents the wavelength, and the vertical axis the power (dB). The laser oscillation lightwave is used as a reference of 0 dB. A peak of an output having a large power appears at an intended wavelength. However, in addition to that, a continuous spectrum having a weak output exists at both sides of the peak. This phenomenon has so far been overlooked. Not only is the phase different but also the wavelength (energy) is different. Here, the weak lightwave is referred to as the natural emission lightwave Σn. In contrast, the lightwave having a specified wavelength emitted by the laser is referred to as the laser oscillation lightwave Λq. The natural emission lightwave Σn is as weak as −40 to −50 dB. However, although weak, the natural emission lightwave exists.
Such a natural emission lightwave is likely to cause the interference in FIGS. 19 and 20. In the case of FIG. 19, the transmission member transmits both the signal lightwave ΛB from the LD2 and the noise lightwave ΛB from the LD1, and they enter the PD2 of the receiving member to be detected. The PD2 receives both the signal lightwave and the natural emission lightwave both having a wavelength of ΛB. The natural emission lightwave is a noise. In FIG. 19, the PD1 receives both the natural emission lightwave of the LD2 and the laser oscillation lightwave of the LD1. Both the PD1 and PD2 receive the noise having the same wavelength as that of the signal lightwave. Even when the multiplexer (WDM) 39 and the demultiplexer (WDM) 42 operate normally, because the wavelength is the same, such a noise cannot be blocked by the WDM. The present invention intends to solve the problem of the interference due to the natural emission lightwave.
So far, the fact has not been known that a semiconductor laser emits a natural emission lightwave having a different wavelength. Consequently, no literature has noticed the problem of interference that occurs when two or more semiconductor laser lightwaves having different oscillation wavelengths are transmitted through the same optical fiber. The present inventor was unable to find a previously published literature that raised such a problem and showed a step to solve it.
The patent literature 1 describes as follows: The oscillation wavelength of a semiconductor laser deviates from a specified value. To solve the problem, the backward light of the semiconductor laser is observed with a photodiode for monitoring the wavelength. When the wavelength deviates, a control circuit of the semiconductor laser returns the wavelength to the specified value. To prevent the backward light from leaking, the heat sink is extended toward the rear. This is an idea of the patent literature 1. The patent literature 1 notices as a problem the variation in the laser oscillation lightwave itself of a semiconductor laser. Then, the variation in the wavelength of the laser oscillation lightwave is prevented. The patent literature 1 does not mention the existence of a natural emission lightwave in addition to the lightwave having the oscillation wavelength Λ. It is likely that the patent literature 1 believes that the total energy is concentrated to the lightwave of the oscillation wavelength. In addition, the patent literature 1 does not raise the problem of interference caused by the natural emission lightwave.    Patent literature 1: the published Japanese patent application Tokukai 2003-229626
As described earlier, in a solid laser and the like, the spontaneous emission lightwaves are lightwaves having the same wavelength as that of the laser oscillation lightwave but having nonuniform phases. It is not recognized that in the case of a semiconductor laser, lightwaves having different wavelengths are emitted. In other words, it is not noticed that something like the natural emission lightwave exists that has a continuous spectrum with different wavelengths as described in the present invention. Consequently, no recognition exists to prevent the interference caused by that. In this field, it can be said that the natural emission lightwave itself in a semiconductor laser is a novel discovery. Therefore, no prior art exists to prevent the interference caused by that. The present inventor was unable to find such a prior art.


An optical gas analyzer, preferably for hydrocarbons, comprises an optical gas cell, an infrared LED pulse radiation source and a radiation detector at the inlet and outlet of the cell, respectively, and a control unit. The detector comprises measuring and reference photovoltaic detectors, a filter window at the detector inlet, and a filter mirror inside the same. Resulting spectral transmission and reflection characteristics of the filter window and filter mirror match the absorption spectrum for the gas and the radiation spectrum of the source. The filter window and filter mirror compensate external influence upon the radiation path trajectory within the cell on the gas concentration result. The cell comprises spherical or parabolic and flat mirrors arranged in a checker order to transmit the beam of the source via a zigzag-like trajectory between the mirrors. The analyzer offers a fast response and high sensitivity along with minimized power consumption and dimensions.

Known has been an infrared absorption gas analyzer (patent RU 2292039, IPC G01N21/61, publ. 2005-02-18), hereinafter referred to as a gas analyzer, that comprises a control unit, an optical gas cell, an infrared radiation (hereinafter referred to as IR) source and an IR detector. The IR radiation source is installed at the cell inlet, while the IR radiation detector is installed at the cell outlet. The control unit is adapted to process the IR radiation, received by the detector, to display the results of the processing. Also, the IR radiation source has a spherical mirror reflector. The optical gas cell includes operational and reference chambers, wherein the operational chamber is shaped like a hollow frustum of a cone with an internal spherical mirror reflector and is installed immediately within the reference chamber in the optical axis with the IR radiation source, whereas the IR radiation detector comprises a focusing unit and is installed along an optical axis perpendicular to the first one. A mirror splitter and a rotating disc with a profile window are placed at the cross point of these axes.
This gas analyzer has such significant disadvantages as:                high energy consumption due to the loss of a substantial energy portion of the IR radiation source at the mirror reflector and due to the IR radiation flow interruption by the disc with a profile window, because only small areas within the wide spectrum of the IR radiation of the source are used;        reduced operational reliability due to having a multitude of mechanical parts, such as, for example, the rotating disc with the profile window and a rotating optical filter; and        increased overall dimensions resulting mainly from a large number of space consuming mechanical parts, and spherical mirror reflectors, with their mutual allocation.
A gas analyzer is known (EPA 2169384, IPC G01N21/35, publ. 2010-03-31) intended for the creation of a multi-component apparatus, to be used within stationary facilities or at mobile medical stations for monitoring human breath gases with sufficient accuracy provided by means of compensating the external influences upon the radiation path trajectory. Herein, this task is solved through the use of an infrared radiation source, a gas cell, a dichroic beam splitter, an analyzing filter, a reference detector, and a measuring detector. In this case, the dichroic beam splitter is adapted to change the beam angle depending on the gas analyzed. The dichroic beam splitter is installed at 45° to the normals of the photodetectors located at 90° to each other.
The disadvantages of this analyzer include large dimensions and high energy consumption.
Known from Russian patent 2372606, IPC G01N21/03, publ. 2009-11-10, is a miniature multi-path mirrored optical cell. The cell fails to protect against temperature external conditions.
Known has been an infrared gas analyzer (U.S. Pat. No. 6,114,700, IPC G01N21/05, publ. Sep. 5, 2000), wherein photovoltaic detectors are used as infrared radiation detectors. However, the use of the photovoltaic detector in the known gas analyzer does not provide a balance of high detectability and fast response.
Also known has been an optical gas sensor device based on the immersion diode optical pairs is known (RU 75885, IPC G01N21/35, publ. Aug. 27, 2008), comprising a gas cell, the reflecting surfaces of which form an optical scheme for generating a probe radiation beam, as well as a probe IR radiation source including a light-emitting diode (LED) and a photodetector including a photodiode, which are mechanically connected to the gas cell body. The gas cell comprises mechanical adjusting elements, the light-emitting diode and photodiode being implemented with the use of immersion optics (immersion diodes) and rigidly connected to the adjusting elements.
The disadvantage of the known device is the use of the immersion diodes, which possess uncontrollable axis misalignment of optical scheme and diagrams. The use of immersion diodes results in the complication of the gas analyzer design due to having to add adjusting devices, and in the increase in dimensions.
Known also has been an infrared band gas analyzer (RU 2287803, IPC G01N21/35, publ. Nov. 20, 2006), comprising a wave power source including a light-emitting diode matrix, emitting a reference and operating wave lengths, a gas cell located along the radiation, a main photodetector installed at the cell outlet to receive the reference and operating wave length radiation, as well as a signal processing unit, comprising analog-to-digital coder (ADC), with its outlet connected to a microprocessor and an indication unit. An additional photodetector is installed at the cell inlet, the both photodetectors including pyroelectric photodetectors.
Each light-emitting diode within the light-emitting diode matrix of this known gas analyzer should have fast response when powered by pulse current, to keep the total power unvarying.
When using such matrix, however, it is impossible to facilitate a simultaneous beaming concentration on a single photodetector for each light-emitting diode within the matrix and, at the same time, to minimize optical unit dimensions. Also, the infrared sources are used in the prior art in conjunction with photodetectors of pyroelectric type.
An optical gas sensor, hereinafter referred to as a gas analyzer and known from EP 1995586, IPC G01N21/03, publ. Nov. 26, 2008, comprises a radiation source, an optical gas cell, and an optical radiation detector. Through the optical gas cell, from the inlet to the outlet thereof, two curved channels are formed for passing IR radiation which is emitted from the source located at the inlet of the optical gas cell and is directed towards the detector installed at the outlet of the above-mentioned cell, the channels being spatially separated, their curve radii fitting the body of the optical gas cell. There is a control unit coupled with the radiation source and the optical radiation detector and adapted to change operation modes of the IR radiation source and to process the IR radiation received by the detector displaying the results obtained therefrom.
This gas analyzer possesses such disadvantages as:                substantial losses of the energy of the IR radiation due to having two curved channels for passing same, as well as due to the necessity of the radiation transfer from one channel to another; and        delayed action in operation resulting from slow gas delivery into the channels due to the gas having to self-diffuse inwards the two channels.
Also known has been a gas monitor comprising IR light-emitting diodes (S. F. Johnston: Gas monitors employing infrared LEDs, Meas. Sci. Technol. 3 (1992) 191-195). A compact version of the monitor provides for registering concentrations of carbon dioxide (CO2). It cannot be used, however, for monitoring methane (CH4) concentrations because, since the absorption factor of CO2 is ten times that of CH4, the monitor for CO2 requires one tenth of optical path length as compared with that for CH4. The impossibility of making a compact version of a hydrocarbon concentration monitor using the design disclosed in Johnston is believed to be a serious drawback of that prior art.
An integrated optical gas sensor known from the GB patent 2401432, IPC G01N21/03, publ. Nov. 10, 2004 and hereinafter referred to as an optical gas analyzer comprises an optical gas cell, an IR radiation source and a detector of this radiation. The optical gas cell is configured to pass IR radiation from its source to the detector of this radiation and is implemented curve-shaped with a rectangular cross-section. A electric bulb is used as a source of IR radiation and is located at the inlet of the cell, and the IR radiation detector is located at the outlet of the cell. There is a control unit coupled with the radiation source and the optical radiation detector and adapted to change operation modes of the IR radiation source and to process the IR radiation received by the detector displaying the results obtained therefrom.
This prior art is selected as the closest analog of the claimed gas analyzer since they have the greatest number of common essential features common with the claimed gas analyzer and are intended to solve similar tasks.
The prior art has such disadvantages as:                substantial infrared radiation energy losses resulting from the curve-shaped implementation of the cell wherein, due to the specificity of the IR radiation reflection from the curved surface of the gas cell internal walls, there is strong dissipation of the radiation energy;        large energy consumption since an electric bulb is used as an IR radiation source, and a pyroelectric detector is used as an IR radiation detector, which results in a control unit to function at low frequencies with lower duty ratio;        a low level of the IR radiation energy registered by the detector due to a large angle of radiation divergence when it leaves the cell and when it reaches the detector, as well as due to the strong IR radiation energy dissipation resulting from the cell curved shape.
Besides, the optical gas cell developed within this design is not capable to concentrate the IR radiation on the detector plane, since it is implemented as a light guide with reflection from its walls.


In various embodiments, a device classification service forms a device cluster by applying clustering to attributes of endpoint devices observed in one or more networks. The device classification service applies an initial device classification rule to the endpoint devices in the device cluster, based on one or more of the endpoint devices in the device cluster matching the initial device classification rule. The device classification service computes metrics for the initial device classification rule that quantify how well the attributes of the endpoint devices in the device cluster match the initial device classification rule. The device classification service decides, based on the metrics, whether to associate the initial device classification rule with the device cluster or generate a new device classification rule based on the device cluster.

An emerging area of interest in the field of computer networking is the "Internet of Things" (IoT), which may be used by those in the art to refer to uniquely identifiable objects/things and their virtual representations in a network-based architecture. In particular, the next frontier in the evolution of the Internet is the ability to connect more than just computers and communications devices, but rather the ability to connect "objects" in general, such as lights, appliances, vehicles, window shades and blinds, doors, locks, etc.
As more non-traditional devices join the IoT, networks may eventually evolve from a bring-your-own-device (BYOD) model to a model that enables bring-your-own-thing (BYOT), bring-your-own-interface (BYOI), and/or bring-your-own-service (BYOS) paradigms. In other words, as the IoT grows, the number of available services, etc., will also grow considerably. For example, a single person in the future may transport sensor-equipped clothing, other portable electronic devices (e.g., cell phones, etc.), cameras, pedometers, or the like, into an enterprise environment, each of which may attempt to access the wealth of new IoT services that are available on the network.
From a networking perspective, the network can automatically configure access control policies, other security policies, and the like, if the device type of a particular device is known to the network. For example, the network may limit a particular type of sensor to only communicating with its supervisory device. Typically, this classification is made by observing the behavior of the device during a short period of time after joining the network (e.g., the first minute) and applying a device classification rule to the observed behavior. However, as networks change over time and/or new networks make use of the classification service, simply generating a new classification rule each time can lead to a cumbersome pool of rules that may even conflict and lead to misclassifications. Conversely, always reusing existing classification rules can also lead to poor accuracy and misclassifications, as well.

Learning when to reuse existing rules in active labeling for device classification


A wireless communication system is provided for establishing wireless communication between a wireless communication apparatus and a battery-driven communication terminal apparatus in which system the power consumption rate of the communication terminal apparatus can be reduced. The wireless communication system includes a trigger signal transmission line for transmitting a trigger signal from the wireless communication apparatus to the communication terminal apparatus, and a data communication line for establishing data communication between the wireless communication apparatus and the communication terminal apparatus. The data communication between the wireless communication apparatus and the communication terminal apparatus is established in response to the trigger signal that is transmitted by the trigger signal transmission line.

1. Field of the Invention
The present invention relates generally to a wireless communication system, an electronic price tag system, a wireless communication apparatus, a communication terminal apparatus, and a wireless communication method, and more particularly to a wireless communication system and apparatus for establishing wireless communication between a wireless communication apparatus and a communication terminal apparatus.
2. Description of the Related Art
Generally, at retail stores, price tags are provided on shelves stocking commodities. In recent years and continuing, with the growing competition between rivaling stores, there is an increasing demand for a system for enabling prices of commodities to be flexibly changed. In view of this trend, a so-called electronic price tag system is being developed that is capable of easily reflecting the changes made to prices of commodities on price tags.
The electronic price tag system includes electronic price tags implementing liquid crystal, for example, which are capable of electrically changing their price displays in response to instructions from a computer, for example. In this way, prices of commodities may be flexibly changed and reflected on the price tags. In the electronic price tag system, the electronic price tags do not have to be replaced when prices of commodities are changed. The electronic price tags are battery-driven and are arranged to be capable of establishing data communication for exchanging data pertaining to prices, for example, through wireless communication.
Since the electronic tags are battery-driven, power consumption rate within the electronic tags is preferably minimized, and in this regard, a wireless communication system using infrared light has been proposed in the conventional art. However, in a wireless communication system using infrared light, the wireless communication may be easily hampered by factors such as obstacles and external light.
In turn, a wireless communication system using a radio communication scheme has been proposed, which system is less vulnerable to factors such as obstacles and noise and are capable establishing data communication with accuracy and reliability. Particularly, a wireless communication system using a wireless communication scheme such as that conforming to the IEEE802.15.1 standard or the IEEE802.15.4 standard is being widely contemplated.
FIG.1 is a diagram illustrating a data communication operation using a radio communication scheme according to the prior art.
According to a communication scheme conforming to the IEEE802.15.1 or IEEE802.15.4 standard, a data request and a data response are periodically exchanged at predetermined time intervals. In such an arrangement, in order to reduce power consumption, a communication IC for realizing the communication scheme may be set to sleep mode during the time in which communication is not being established, and the communication IC may be set to data mode only when a data request and a data response are being exchanged (i.e., when data communication is established). However, in such a case, a data request and a data response still have to be exchanged at predetermined time intervals, and thereby, as is shown in FIG. 1, a communication apparatus is switched between sleep mode and data mode several times per second.
It is noted that the power consumption level during data communication may reach up to several dozen mA. However, the price of a commodity at a store may only be changed a few times within one day. In other words, in the above-described arrangement, a communication apparatus is switched between sleep mode and data mode several times per second even though actual data communication is rarely conducted, and thereby, a large amount of power is wasted. As a result, the service life of a battery of an electronic price tag is needlessly reduced.

Wireless communication system, electronic price tag system, wireless communication apparatus, communication terminal apparatus, and wireless communication method


An apparatus for detecting Deep Vein Thrombosis (DVT) in a patient includes a computer based device, a device disposed on a predetermined position on a calf of the patient for measuring blood volume, another device for measuring temperature of the calf and still another device for measuring calf size. A cuff is operably connected to the computer based device and envelops a portion of a thigh of the patient and is controllably restrictable by the computer based device to produce a controlled venous occlusion of the patient's deep veins for a predetermined period. A method for detecting DVT using the device is also provided.

1. Field of the Invention
The present invention is generally directed to apparatus and method for detecting venous obstruction. More particularly, but not by way of limitation, the invention is directed to apparatus and method for detecting DVT in a patient by measuring blood volume, temperature, calf size and other clinical indications.
2. Related Art
There exist many methods for detection of obstruction in a human's circulatory system. Depending upon which part of the circulatory system is examined, a particular method may or may not lend itself as well to detecting obstructions. Methods employing invasive, i.e., surgical techniques, are a last resort due to their inherent severity and limitations in repeated use.
Non-invasive devices have hence been preferred in the diagnosis of venous obstruction. Ultrasonic devices have been used to study venous thrombosis in the deep veins, but are limited in that these require highly skilled operators, thus rendering subjective uncertainty in their resulting diagnosis.
Other devices measure arterial elasticity to determine whether sclerosis exists in the artery. Such devices have employed photoelectric plethysmography to monitor the change in transmitted light intensity across tissues, such as fingers, to diagnose sclerosis.
Still others have used inflatable cuffs which wrap about a limb and measure diastolic and systolic pressure to detect peripheral arterial disease. Others have coupled cuffs with impedance plethysmography to detect atherosclerosis. Also, there has been use of light reflective rheography on the ankle for detection of chronic venous insufficiency.
Although there exist various apparatuses and methods of detecting venous and arterial irregularity, there remains a great need to improve apparatuses and methods for the detection of DVT. Specifically, the existing devices which detect DVT by measuring venous outflow such as impedance plethysmography or strain-gauge plethysmography, are not consistent from patient to patient, require highly developed operator skill, and are unable to detect chronic proximal DVTs or acute/chronic distal DVTs. The present invention, through the use of multiple risk factor analysis and artificial intelligence algorithms is able to overcome the shortcomings of the prior art devices and provide a significantly improved apparatus for detecting DVT.

Apparatus and method for detecting deep vein thrombosis


A supply of lancets for a multi-use lancing device are carried by a tape and sequentially brought from a storage position to an activating position by advancing the tape around a bend. In the lancets' activating position they extend from the tape such that their sharp tips are available for lancing tissue. The carrying tape can be arranged in reel-to-reel format in a housing having a lancing opening. The lancets can be integral with the tape and activated to move the lancet through the lancing opening by moving the tape along its tape path or by translating a dedicated service loop of the tape. The lancets can also be independent from the tape and activated through the lancing opening by a separate lancing actuator. A test media can be included on the carrying tape and the housing can contain a sensor to yield an integrated lancing and testing device.

The present invention generally relates to bodily fluid sampling and more specifically, but not exclusively, concerns bodily fluid sampling devices having a supply of sterile lancets carried by a tape.
The acquisition and testing of bodily fluids is useful for many purposes, and continues to grow in importance for use in medical diagnosis and treatment, and in other diverse applications. In the medical field, it is desirable for lay operators to perform tests routinely, quickly and reproducibly outside of a laboratory setting, with rapid results and a readout of the resulting test information. Testing can be performed on various bodily fluids, such as blood and/or interstitial fluid. Such fluids can be tested for a variety of characteristics of the fluid, or analytes contained in the fluid, in order to identify a medical condition, determine therapeutic responses, assess the progress of treatment, and the like.
The testing of bodily fluids begins with obtaining the fluid sample. One method of acquiring the fluid sample involves inserting a hollow needle or syringe into a vein or artery in order to withdraw a blood sample. However, such direct vascular blood sampling can have several limitations, including pain, infection, and hematoma and other bleeding complications. In addition, direct vascular blood sampling is not suitable for repeating on a routine basis, can be extremely difficult and is not advised for patients to perform on themselves.
The other common technique for collecting a blood or other bodily fluid sample is to form an incision in the skin to bring the fluid to the skin surface. According to this technique, a lancet, such as a needle, knife or other cutting instrument, is used to form the incision in the skin. The resulting blood or interstitial fluid specimen may then be collected in a small tube or other container, or placed directly in contact with a test strip or otherwise analyzed. Because lancets are necessarily sharp, lancing devices are typically constructed to protect the lancets when not in use to avoid injuries and contamination.
However, many existing lancing devices are generally designed to hold a single lancet and after lancing require manual replacement of the lancets before performing a subsequent lancing. Particularly where an individual needs to obtain multiple samples per day, it can be inefficient and inconvenient to carry a separate supply of lancets or to use a separate device for each lancing event. A self contained multi-use lancing device could avoid the problems of manually replacing a used lancet, but there are challenges in designing a multi-use lancing device that can safely and reliably handle the lancets yet is compact in design and simple for a lay operator to use and which is also economical to manufacture. Accordingly, there is a need in the art for a multi-use lancing device that meets some or all of these challenges. In one form, the present invention addresses this need and provides a multi-use lancing device that is simple and safe for a lay operator to use and that is cost-effective to manufacture. In other forms the present invention provides other advancements in the art.

Lancets for bodily fluid sampling supplied on a tape