A video camera system which can automatically avoid a mismatch that occurs between camera setting values on the PC side and camera setting values on the video camera side immediately after the connection therebetween. A video camera includes a controlled unit capable of being externally controlled in accordance with information inputted from a second data communication node. A control device includes a control unit for outputting the information to control the video camera from a first data communication node, a storage unit for storing at least one preset imaging device control condition, a control condition changing unit for changing the imaging device control condition stored in the storage unit, a detecting unit for detecting whether the control device and the video camera are connected, and an output unit started up in response to a detection signal from the detecting means for reading the imaging device control condition stored in the storage unit and outputting the read control conditions from the first data communication node.

1. Field of the Invention
The present invention relates to apparatus and method for outputting a command from outside of a device to change a control method of the device to execute an operation different from that actuated by remote control executed by the device""s control unit.
2. Description of the Related Art
Hitherto, peripheral devices of a personal computer (referred to as a PC hereinafter), such as a hard disk and a printer, have been connected to the PC through a universal interface for small computers, e.g., a digital interface (referred to as a digital I/F) such as a SCSI, for data communication.
Digital cameras and digital video cameras are also regarded as input means to a PC and are also peripheral devices. Recently, the technology of transferring images (such as still and motion pictures picked up by digital cameras and video cameras) into a PC along with accompanying voice signals, storing the pictures in a hard disk or editing them in the PC, and then color-printing the pictures using a printer has been developed and has gained popularity.
When such image data is outputted from the PC to the printer or to the hard disk, the data is communicated via the above-mentioned SCSI or the like. On that occasion, a versatile digital I/F having a high transfer data rate, such as the SCSI, is required for sending a large amount of data.
However, such conventional digital I/Fs are still inconvenient in many points because some of them have a low data transfer rate, or employ large-diameter cables for parallel communication, or have limitations in type and connecting scheme, or require I/F connectors in the same number as destinations to be connected.
Furthermore, in many of the general PCs and digital equipment for use at home, a connector for connection to a SCSI cable is provided on the back side of the PC. Such a connector has a relatively large size, and it is rather troublesome to couple the cable to the connector.
When connecting, to PCs, portable equipment (such as digital cameras and video cameras) must be connected to connectors on the PC back side at every use, which is very troublesome for users.
Digital data communication has been used for mutual communication between a PC and such peripheral devices, and has utilized conventional communication techniques. It is however expected in the future that the types of devices using digital data will increase, and an improvement of I/Fs can improve network communication among many interconnected digital devices including PC peripheral devices to include digital video cameras, digital storage medium playback apparatuses, etc. If so, such network communication will be very convenient for users. On the other hand, since such communication will often transfer an extremely large amount of data, the use of conventional communication techniques will make the network crowded and adversely affect the communication between other devices in the network.
In view of the above, a method has been proposed to overcome the problems encountered in the conventional digital I/Fs, and to employ a universal digital I/F (e.g., IEEE 1394-1995 High Performance Serial Bus) equipped on each piece of digital equipment in conformity with a unified standard for communication between all the types of digital equipment including PCs and peripheral devices thereof. Thus, the proposed method intends to realize data communication among devices when a PC, a printer and other peripheral devices, a digital camera, a digital VTR, a camcoder, etc. are connected to each other in the form of a network.
The IEEE 1394 I/F has several remarkable advantages. Because of high-speed serial communication, though described later in detail, a cable is relatively thin and highly flexible, and the connector size is much smaller than the case of using a SCSI cable. Further, a large amount of data such as image information can be transferred at a high speed along with device control data. In other words, communication using the IEEE 1394 I/F is greatly advantageous in that when connecting portable equipment (such as digital cameras and video cameras), the connection work is much less troublesome for users, and image information can be more easily transferred to PCs.
The IEEE 1394 serial bus will be described below in more detail.
(Technical Outline of IEEE 1394)
With the advent of home digital VTRs and DVD players, it has been required to support data transfers of large amounts of information (such as video data and audio data) in real time. In order to transfer such data in real time, and to input such data into a PC or transfer them to another piece of digital equipment, an interface is needed which has a required transfer function and is able to transfer data at a high speed. The IEEE 1394-1995 (High Performance Serial Bus) (referred to as the 1394 serial bus hereinafter) is an interface that has been developed from the above point of view.
FIG. 7 shows an example of a network system made up by using 1394 serial buses. The network system includes devices A, B, C, D, E, F, G and H. Twisted pair cables constituting 1394 serial buses are employed to interconnect between A and B, between A and C, between B and D, between D and E, between C and F, between C and G, between C and H. The devices A to H comprise, e.g., a PC, a digital VTR, a DVD player, a digital camera, a hard disk, a monitor, etc.
The devices can be interconnected in a mixed fashion of a daisy chain system and a node branch system with a high degree of flexibility.
Also, each device has its own specific ID, and recognizes the IDs of the other devices which constitute a network devices interconnected by the 1394 serial buses. Thus, just by connecting two pieces of digital equipment successively with one 1394 serial bus, one network is constructed by devices each of which has a relay function. The entire network has the feature of the 1394 serial buses, i.e., a function of automatically recognizing network devices, their connection status, etc. based on the plug and play function at the time when the bus cables are connected to the devices.
Further, when some device is removed from or newly added to the network as shown in FIG. 7, the bus reset is automatically made to reset the network configuration, and a new network is formed. This function makes it possible to always set and recognize the network configuration from time to time.
The 1394 serial buses allow data transfer rates of 100/200/400 Mbps. Devices having higher data transfer rates support the lower data transfer rates for compatibility between the devices.
As data transfer modes, there are an asynchronous transfer mode for transferring asynchronous data (referred to as Asynch data hereinafter) such as a control signal, and an isochronous transfer mode for transferring isochronous data (referred to as Iso data hereinafter) such as real-time video data and audio data. The Asynch data and the Iso data are transmitted in a mixed fashion within each cycle (being usually 125 xcexcs) with a higher priority given to the Iso data, following transfer of a cycle start packet (CSP) which indicates the start of the cycle.
FIG. 8 shows constituent elements of the 1394 serial bus.
The 1394 serial bus is of a layered structure in its entirety. As shown in FIG. 8, the core of hardware components is a 1394 serial bus cable. A connector of the cable is connected to a connector port, and a physical layer and a link layer exist as other hardware components at a level higher than the connector port.
Those two hardware components essentially constitute an interface chip. The physical layer executes coding, control related to the connector, etc, and the link layer executes packet transfer, control of cycle time, etc.
A transaction layer (as one of the firmware components) manages data to be subjected to transfer (transaction), and issues commands such as Read and Write. A serial bus management (as the other firmware component) manages connection status of the devices connected to the bus, IDs, and the network configuration.
The above-described hardware and firmware components essentially construct the 1394 serial bus.
An application layer (as a software component) varies depending on the software used. The application layer specifies a manner of placing data on the interface, and is specified by a protocol such as an AV protocol.
The 1394 serial bus is constructed as described above.
Next, FIG. 9 shows an address space in the 1394 serial bus.
The devices (nodes) connected to the 1394 serial bus are each given with its own specific 64-bit address, without exceptions. The node addresses are stored in a ROM so that each device can always recognize its own and other addresses, and can perform communication with a partner designated.
Addressing of the 1394 serial bus conforms with the IEEE 1212 standards. Specifically, the node address is set as follows. The first 10 bits are used for designating the bus number, and the next 6 bits are used for designating the node ID number. The remaining 48 bits represent an address width allocated to the device, and can be used as a specific address space. The last 28 bits represent a specific data area in which information necessary for identifying the device and designating service conditions thereof are stored.
The technical outline of the IEEE 1394 serial bus has been described above.
The technical features of the IEEE 1394 serial bus will now be described in more detail.
(Electrical Specifications of IEEE 1394 Serial Bus)
FIG. 10 shows a section of the 1394 serial bus cable.
In the connecting cable of the 1394 serial bus, power lines can be disposed in addition to two sets of twisted signal line pairs. With the provision of the power liens, power can be supplied to, e.g., a device having no power supply, or to a device having a voltage lowered due to a failure.
Alternatively, a simplified connecting cable may exclude power lines under conditions which restrict devices to which the cable may be connected.
Power supplied through the power lines is specified to have a voltage of 8 to 40 V and a maximum DC current of 1.5 A.
(DS-Link Coding)
FIG. 11 is a chart for explaining a DS-Link coding method of a data transfer format employed for the 1394 serial bus.
The 1394 serial bus employs a DS-Link (Data/Strobe-Link coding method. The DS-Link coding method is suitable for high-speed serial data communication, and requires two signal lines. Of a pair of twisted lines, one line serves to transmit primary data, and the other line serves to transmit a strobe signal.
On the receiving side, a clock can be reproduced by taking the exclusive logical sum of data and strobe.
The merits of employing the DS-Link coding method are described below. Transfer efficiency is higher than other serial data transfer methods. No need of a PLL circuit reduces the circuit scale of a controller LSI. When there is no data to be transferred, it is not required to transmit information indicating an idle state. Accordingly, a transceiver circuit of each device can be brought into a sleep state, and power consumption can be reduced.
(Bus Reset Sequence)
In the 1394 serial bus, the devices (nodes) connected to the bus are each given a specific node ID, and recognized as one of the nodes of a network configuration.
When it is required to recognize a new network configuration upon a change of the network configuration, e.g., upon the number of nodes being increased or reduced due to insertion or removal of a node or a power-on/off in the node, each node having detected such a change transmits a bus reset signal on the bus, and goes into a mode for recognizing a new network configuration. At this time, such a change is detected by sensing a change of the bias voltage on a 1394 port board.
At soon as one node transmits a bus reset signal and the physical layer of another node receives the bus reset signal, the occurrence of a bus reset is indicated from the physical layer to the link layer, and the bus reset signal is further transmitted to still another node. After all the nodes have finally received the bus reset signal, the bus reset is started up.
The bus reset is started up when a hardware change, such as insertion or removal of the cable or an abnormal condition of the network, is detected as described above, or when a command is directly issued to the physical layer under host control in accordance with the protocol.
Also, data transfer is temporarily suspended upon the start-up of the bus reset, and is held in a standby state during the suspension. After the suspension, data transfer is restarted under a new network configuration.
The bus reset sequence has been described above.
(Node ID Determining Sequence)
After the bus reset, the nodes start the operation for allocating IDs to themselves to construct a new network configuration. A general sequence from the bus reset to the determination of node IDs will be described below with reference to flowcharts of FIGS. 19, 20 and 21.
The flowchart of FIG. 19 shows a sequence of steps executed on the bus from the bus reset until the node IDs are determined to permit start of data transfer.
First, in step S101, it is always monitored whether a bus reset occurs in the network. If the bus reset occurs due to, e.g., power-on/off in the node, the processing goes to step S102.
In step S102, parent-child relation is declared between nodes, which are directly connected to each other, for determining the connection status of a new network from the reset state of the network. If parent-child relations are decided between all the nodes in step S103, one root is decided in step S104. Until parent-child relations are decided between all the nodes, the declaration of parent-child relation in step S102 is repeated and the root is not decided.
If the root is decided in step S104, the processing goes to step S105 in which the node ID setting operation is carried out to allocate IDs to the nodes. The node ID setting operation is repeated to set the node IDs in a predetermined node sequence until all the nodes are given their own IDs. If all the nodes are completely given the IDs in step S106, this means that the new network configuration has been recognized by all of the nodes. In step S107, therefore, the bus comes into a state capable of performing data transfer between the nodes, and the data transfer is started.
Subsequent to the state of step S107, the bus is brought again into the mode of monitoring the occurrence of the bus reset in the network. If the bus reset occurs, the node ID setting operation from step S101 to step S106 is repeated.
The flowchart of FIG. 19 has been described above. FIGS. 20 and 21 are flowcharts showing in more detail a process from the bus reset to the determination of the root and a process from the determination of the root to the end of the ID setting, respectively, in the flowchart of FIG. 19.
The flowchart of FIG. 20 will be first described.
If the bus reset occurs in step S201, the network configuration is once reset.
It is always monitored in step S201 whether a bus reset occurs in the network.
Then, in step S202, a flag indicating that the device is a leaf (node) is set in each such device as a first step of the operation for recognizing the connection status of the reset network. Thereafter, in step S203, it is checked how many ports provided in each device itself are connected to other nodes.
The number of ports not yet defined (i.e., for which a parent-child relation is not yet decided) is checked in step S204 for starting the declaration of parent-child relations depending on the number of ports obtained in step S204. Immediately after the bus reset, the number of ports is equal to the number of ports not yet defined. However, the number of ports not yet defined, which is detected in step S204, varies as the decision of parent-child relation progresses.
Immediately after the bus reset, the node for which parent-child relation can be first declared is limited to only a leaf. Whether the node is a leaf can be recognized by confirming the number of ports checked in step S203. In step S205, the leaf declares xe2x80x9cI am a child and a partner is a parentxe2x80x9d for the node to which the leaf is connected, thereby ending the process.
For the node which has been recognized in step S203 as having a plurality of ports and being a branch, the number of not-yet-defined ports  greater than 1 is determined in step S204 immediately after the bus reset. Accordingly, the processing goes to step S206 in which a flag indicating a branch is set. Then, in step S207, the node waits for accepting xe2x80x9cparentxe2x80x9d based on the declaration of parent-child relation from the leaf.
For the branch having accepted in step S207 the declaration of parent-child relation from the leaf, the control flow returns to step S204 to confirm the number of ports not yet defined. If the number of ports not yet defined is one, this means that the declaration of xe2x80x9cI am a child and a partner is a parentxe2x80x9d in step S205 can be made for the node which is connected to the remaining port. For the branch having two or more ports not yet defined as a result of the second or later confirmation in step S204, the processing goes to step S207 again to wait for accepting xe2x80x9cparentxe2x80x9d based on the declaration of parent-child relation from the leaf or another branch.
Finally, if the number of ports not yet defined becomes zero as a result of the confirmation in step S204 for any one branch or a leaf as an exceptional case (because the leaf has not operated so fast though it can declare xe2x80x9cchildxe2x80x9d), this means that the declaration of parent-child relation is completed for the entire network. For only one node for which the number of ports has not yet been confirmed to be zero (i.e., for which all ports have been decided as parent ports), a flag indicating a root is set in step S208. Then, in step S209, that node is recognized as a root.
In this way, the process from the bus reset to the declaration of parent-child relation for all the nodes in the network, shown in FIG. 20, is completed.
Next, the flowchart of FIG. 21 will be described.
Since flag information indicating a leaf, branch or root is set for each node in the sequence of steps shown in FIG. 20, the nodes are classified in step S301 based on the flag information.
In the operation of allocating IDs to the nodes, the node which can first set an ID is a leaf. IDs are set by allocating numbers increasing from zero (i.e., node number =0xe2x88x92) in the order of leaf, branch and root.
In step S302, the number N (N is a natural number) of leaves present in the network is set. After that, in step S303, each leaf requests the root to give an ID to the leaf. If there are a plurality of requests, the root carries out arbitration between the requests (operation of selecting one request) in step S304. In step S305, an ID number is given to one node which has won the arbitration, and a failure in ID setting is provided to the nodes which have been defeated in the arbitration. Each leaf which has failed in acquiring ID issues an ID request again in step S306, followed by repeating the steps mentioned above. In step S307, the leaf which has succeeded in acquiring an ID number broadcasts its own self-ID packet to all the nodes.
The self-ID packet contains ID information of the node, the number of ports of the node, the number of ports already connected, information indicating whether each port is a parent or a child, information indicating whether the node has an ability allowing the node to serve as a bus manager (if the node has such an ability, a contender bit in the self-ID packet is set to 1, and if the node does not have such an ability, the contender bit is set to 0), etc.
The ability allowing the node to serve as a bus manager means such an ability that the node can perform the four kinds of bus management set forth below.
(1) Bus Power Management
The node can determine whether each of the devices on the network constructed as shown in FIG. 7 is required to be supplied with power through the power lines in the connecting cable, or whether each device is supplied with power independently. Also, the node can manage the time when power is supplied to each device.
(2) Keeping of Speed Map
The node can maintain communication speed information of the devices on the network.
(3) Keeping of Network Structure (Topology Map)
The node can maintain information regarding a tree structure of the network as shown in FIG. 12.
(4) Optimization of Bus Based on Information Obtained from Topology Map
The node (which is selected as a bus manager through later-described procedures) performs the bus management in the entire network.
Also, the node having the ability to serve as a bus manager (i.e., the node broadcasting the self-ID packet with the contender bit set to 1) stores information in the self-ID packet broadcast from each of the remaining nodes, and other information such as communication speeds. When that node is selected as a bus manager, it constructs a speed map and a topology map based on the stored information.
After one node has broadcast the node ID information, the number of remaining leaves is counted down by one in step S308. If the number of remaining leaves is not less than one in step S309, the above-described process from the operation of requesting ID in step S303 is repeated. Finally, if all the leaves have broadcast the node ID information, N=0 is satisfied in step S309 and the processing goes to an ID setting process for branches.
The ID setting of branches is performed in a like manner to the ID setting of leaves.
First, in step S310, the number M (M is a natural number) of branches present in the network is set. After that, in step S311, each branch requests the root to give an ID to the branch. In response to requests, the root carries out arbitration between the requests in step S312. ID numbers increasing from the last number given to the leaf are allocated to respective branches successively starting from the branch which has first won the arbitration. In step S313, the root provides the ID information (or a failure result) to each of the branches having requested IDs. Each branch which has failed in acquiring an ID issues an ID request again in step S314, followed by repeating the steps mentioned above.
In step S315, the branch which has succeeded in acquiring the ID number broadcasts its own self-ID packet to all the nodes. After one node has broadcast the node ID information, the number of remaining branches is counted down by one in step S316. If the number of remaining branches is not less than one in step S317, the above-described process from the operation of requesting an ID in step S311 is repeated until all the branches finally broadcast the node ID information. If all the branches acquire the node IDs, M=0 is satisfied in step S317, thereby ending the branch ID setting mode.
At a point in time after the above branch ID setting mode is ended, the node which has not yet acquired ID information is only a root. Therefore, a number next to the largest among the numbers having been already allocated to the other nodes is set as the ID number of the root in step S318, and the root broadcasts its own self-ID packet in step S319.
Through the process described so far, it becomes apparent which node has the ability to serve as a bus manager. If a plurality of nodes finally have an ability to serve as a bus manager, the node having the largest ID number is selected as the bus manager.
When the root has the ability to serve as the bus manager, the root is selected as the bus manager because its ID number is the largest in the network. When the root does not have the ability to serve as the bus manager, the root which has the second largest ID number (as compared with that of the root and the contender bit in the self-ID packet is set to 1) is selected as the bus manager. Which node has been selected as the bus manager can be ascertained by all the nodes as a matter recognized by all of them because each node broadcasts its own self-ID packet at the time of acquiring the ID number in the process shown in FIG. 21 and each node keeps the information in the self-ID packets broadcast from the other nodes.
The procedures for setting IDs of all the nodes and the bus manger after determining the parent-child relation for each node, as shown in FIG. 21, are thus ended.
Next, the operation in the actual network shown in FIG. 12 will be described, by way of example, with reference to FIG. 12.
The network shown in FIG. 12 has a hierarchical structure such that the nodes A and C are directly connected to the (root) node B at a level lower than the latter, the node D is directly connected to the node C at a level lower than the latter, and the nodes E and F are directly connected to the node D at a level lower than the latter. The procedures for deciding the hierarchical structure, the root node, and the node IDs will be described below.
After the bus reset, the declaration of parent-child relation is fist made between ports of the nodes, which are directly connected to each other, for recognizing the connection status of each node. The parent-child relation means that the parent side lies at a higher level and the child side lies at a lower level in the hierarchical structure.
In the network of FIG. 12, the node which has first declared parent-child relation after the bus reset is the node A. Basically, the declaration of parent-child relation can be started from a node (called a leaf) in which only one port is connected to another node. Such a node can detect by itself that only one port thereof is connected to another node. Upon detecting the fact, the node recognizes that it is positioned at the end of the network. Then, the parent-child relation is successively decided from the node which has finished the recognizing operation at the earliest timing. The port of the node which has declared a parent-child relation (e.g., the node A between A and B) is set to a child, whereas the port of the partner node (the node B) is set to a parent. As a result, the nodes A and B, the nodes E and D, and the nodes F and D are decided respectively as a child and a parent.
The declaration process then moves up a rank. The declaration of parent-child relation is likewise made toward an upper level node successively from one of nodes having a plurality of ports connected (called a branch) which has earlier accepted the parent-child relation from another node. In the network of FIG. 12, after the parent-child relation has been decided between D and E and between D and F, the node D first declares parent-child relation to the node C. As a result, the nodes D and C are decided respectively as a child and a parent.
After accepting the declaration of parent-child relation from the node D, the node C declares parent-child relation to the node B which is connected to the other port of the node C. As a result, the nodes C and B are decided respectively as a child and a parent.
As described above, the hierarchical structure shown in FIG. 12 is constructed, and the node B, for which all ports thereof connected to the other nodes have been finally decided as parents, is decided as a root node. One network system includes only one root.
While the node B is decided as a root node in FIG. 12, the root node could possibly shift to another node if the node B (having accepted the declaration of a parent-child relation from the node A) declares a parent-child relation to another node at an earlier time. In other words, any node has the possibility to become the root node depending on the timing at which its declaration of a parent-child relation is transmitted, and a certain node is not always decided as the root node even in the same network configuration.
After deciding the root node, the network enters the mode of deciding node IDs. In this mode, each node provides its own node ID to all of the other nodes (broadcasting function).
Self-ID information of the node contains the self-node number, information regarding the position at which it is connected, the number of ports possessed by the node, the number of ports connected to other ports, information regarding parent-child relation for each port, etc.
The procedures for allocating the node ID numbers can be started from one of nodes (leaves) each having only one port connected to another node. The node ID numbers =0, 1, 2, . . . are then allocated in sequence to those nodes.
Upon receiving the node ID number, each node broadcasts self-ID information containing the node ID number to all of the other nodes. This permits the other nodes to recognize that the broadcast ID number has been already allocated.
After all the leaves have acquired their own node IDs, the mode proceeds to the operation of deciding IDs of branches, and increasing node ID numbers subsequent to the largest number given to the last leaf are allocated to the branches successively. As with the leaves, upon receiving the node ID number, each branch broadcasts self-ID information in sequence with all of the other nodes. Finally, the root node broadcasts self-ID information. Thus the root always has the largest node ID number.
As described above, node ID numbers are allocated to all the nodes in the entire the hierarchical structure, the network configuration is reconstructed, and the bus initialization is completed.
(Arbitration)
In the 1394 serial bus, arbitration for the right of using the bus is always performed prior to data transfer. The 1394 serial bus constructs such a logical bus type network that each of devices individually connected to the bus relays a signal transferred to it, whereby the same signal is transmitted to all the devices in the network. Accordingly, arbitration is essential for the purpose of avoiding collision between packets. The arbitration enables only one node to transfer a packet at a certain time.
The arbitration will be described below with reference to FIG. 13A which illustrates a process of requesting the right of using the bus, and FIG. 13B which illustrates a process of permitting/rejecting the use of the bus.
Upon the start of arbitration, one or several nodes issue requests the right of using the bus toward the corresponding parent nodes. In FIG. 13A, the nodes C and F are nodes issuing requests for the right of using the bus. The parent node having received the request (i.e., the node A in FIG. 13A) further issues (relays) a request for the right of using the bus toward the succeeding parent node. Those requests finally reach the root which performs the arbitration.
The root node having received the requests for the right of using the bus decides which node is permitted to use the bus. The arbitration process can be executed by only the root node, and the node which has won the arbitration is given with the right of using the bus. In FIG. 13B, the use of the bus is permitted to the node C, and the node F is rejected from using the bus. A DP (Data Prefix) packet is sent to the node which has been rejected in the arbitration, thereby informing the node that the use of the bus has been rejected. The request for the right of using the bus, which has been issued from the rejected node, is left standing to wait for the next arbitration.
The node, which has won the arbitration and has gained permission for the use of the bus, can start data transfer subsequently.
A sequence of the arbitration steps will now be described with reference to a flowchart of FIG. 22.
When the node starts data transfer, the bus must be in an idle state for enabling the data transfer to start. Whether a preceding data transfer is ended and the bus is in an idle state at present can be recognized by checking the lapse of a predetermined idle time gap length (e.g., a subaction gap) which is uniquely set for each transfer mode. If the subaction gap has lapsed, each node determines that the node itself can start the data transfer.
In step S401, it is determined whether the predetermined gap length corresponding to data to be transferred (such as Asynch data or Iso data) is obtained. Unless the predetermined gap length is obtained, any node cannot request the right of using the bus that is needed for starting the data transfer. Accordingly, each node waits until the predetermined gap length is obtained.
If the predetermined gap length is obtained in step S401, it is determined in step S402 whether there is data to be transferred. If so, the processing goes to step S403 in which each node issues a request for the right of using the bus to the root for securing the bus to start the data transfer. At this time, a signal representing the request for the right of using the bus is transmitted so as to finally reach the root after being relayed from one to another device in the network, as shown in FIG. 13. If there is no data to be transferred in step S402, the node goes into a standby state.
Then, if the root receives in step S404 one or more requests for the right of using the bus issued in step S403, the root checks the number of nodes requesting the use of the bus in step S405. If the number of nodes requesting the use of the bus is equal to one in step S405 (i.e., if only one node has issued the request for the right of using the bus), the right of using the bus immediately thereafter is granted to that node. If the number of nodes requesting the use of the bus is more than one in step S405 (i.e., if a plurality of nodes have issued requests for the right of using the bus), the root performs a arbitration process in step S406 for deciding one node which is allowed to use the bus. The arbitration process is made impartial so that permission is not given to the same node at every time, but the right of using the bus is equally permitted to all the nodes.
In step S407, the plurality of nodes requesting the use of the bus in step S406 are classified into one node which has gained the right of using the bus as a result of the arbitration performed by the root, and the other nodes which have been rejected in the arbitration. Then, in step S408, the root transmits a permission signal to one node which has gained the right of using the bus as a result of the arbitration, or the node which has gained the right of using the bus without the arbitration because the number of nodes requesting the use of the bus is equal to one in step S405. Immediately after receiving the permission signal, the node starts the transfer of data (a packet to be transferred). In step S409, the root transmits a DP (Data Prefix) signal indicating a failure in the arbitration to each of the nodes which has been rejected in the arbitration in step S406 and rejected from using the bus. The node having received the DP packet returns to step S401, and then waits until the predetermined gap length is obtained, followed by issuing the requests for the right of using the bus to start the data transfer.
The arbitration process has been described above with reference to the flowchart of FIG. 22.
(Asynchronous Transfer)
In asynchronous transfer, data is transferred in an asynchronous manner. FIG. 14 shows state transitions over time in the asynchronous transfer mode. The first subaction gap in FIG. 14 represents an idle state of the bus. At the time when the idle time has reached a certain value, the node desiring to start the data transfer determines that the bus is available, following which the arbitration is executed to secure the bus.
After gaining permission of the use of the bus as a result of the arbitration, the data transfer is executed in the form of a packet. After the data transfer, the node having received the data responds to the data transferred to it by sending back an ACK (return code for confirming reception) as a result of the reception after a short gap called the ACK GAP, or by transmitting a response packet, whereupon the packet transfer is completed. The ACK comprises information of 4 bits and checksum of 4 bits. The ACK includes information indicating whether the destination node of the transmission has succeeded in receiving the data, or whether it is in a busy state or a pending state, and is sent back to the source node at once.
Next, FIG. 15 shows an example of a packet format for use in the asynchronous transfer mode.
A packet comprises a data portion, a data CRC for error correction, and a header portion. The destination node ID, the source node ID, the length of transferred data, various codes, etc. are written in the header portion as shown in FIG. 15, and then transferred.
Also, the asynchronous transfer is communication carried out in one-to-one relation from some node to a partner node. A packet transferred from the source node is routed to all the nodes in the network, but the node ignores the packet having an address other than belonging to itself. Accordingly, the packet is read by only one destination node.
The asynchronous transfer has been described above.
(Isochronous Transfer)
In isochronous transfer, data is transferred in an isochronous manner. The isochronous transfer, which can be the biggest feature of the 1394 serial bus, is a transfer mode suitable for multimedia such as video data and voice data, particularly, which require real-time transfer.
Also, while the asynchronous transfer is a one-to-one relation transfer, the isochronous transfer renders a packet to be transferred from one source node equally to all the other nodes with the broadcasting function.
FIG. 16 shows state transition over time in the isochronous transfer mode.
The isochronous transfer is executed with certain time intervals on the bus. This time interval is called an isochronous cycle. The time of one isochronous cycle is 125 xcexcs. A cycle start packet indicates the start time of each cycle, and serves to perform time adjustment for each node. The cycle start packet is transmitted by a node called a cycle master. After a predetermined idle period (subaction gap) has elapsed subsequent to the end of packet transfer in the preceding cycle, the cycle master transmits the cycle start packet indicating the start of the current cycle. The time interval at which the cycle start packet is transmitted is 125 xcexcs.
Also, as indicated by channels A, B and C in FIG. 16, plural types of packets can be separately transferred in one cycle by allocating channel IDs to those packets respectively. This enables packets to be transferred in real time between a plurality of nodes at the same time. The node on the receiving side takes in data of only the packet assigned with the channel ID that is desired by the node itself. The channel ID does not represent the address of the destination of transmission, but merely indicates a logical number (or character) given to each packet data for discrimination. Therefore, when some packet is transmitted, the packet is broadcast so that it is routed from one source node to all of the other nodes.
Prior to transmitting a packet in the isochronous transfer mode, arbitration is performed as with the asynchronous transfer mode. However, because the isochronous transfer mode is not a one-to-one communication (unlike the asynchronous transfer mode), there is no ACK (return code for confirming reception) in the isochronous transfer mode.
Further, an ISO GAP (isochronous gap) shown in FIG. 16 represents an idle period necessary for recognizing that the bus is in an idle state, prior to starting the isochronous transfer. At the time when the predetermined idle period has elapsed, the node desiring to start the isochronous transfer determines that the bus is in an idle state, following which an arbitration is conducted before the packet transfer can be executed.
Next, FIG. 17 shows an example of a packet format for use in the isochronous transfer mode.
Various packets are separated into channels and each comprises a data portion, a data CRC for error correction, and a header portion. The length of transferred data, the channel No., various codes, a header CRC for error correction, etc. are written in the header portion as shown in FIG. 17, and then transferred.
The isochronous transfer mode has been described above.
(Bus Cycle)
In actual transfer on the 1394 serial bus, the isochronous transfer and the asynchronous transfer can be executed in mixed fashion. FIG. 18 shows transfer state transitions on the bus over time when the isochronous transfer and the asynchronous transfer are executed in mixed fashion.
The isochronous transfer is executed in preference to the asynchronous transfer. The reason is that after the cycle start packet, the isochronous transfer can be started with a shorter gap length (isochronous gap) than the gap length (subaction gap) of an idle period required for starting the asynchronous transfer. Accordingly, execution of the isochronous transfer is given with higher priority than that of the asynchronous transfer.
In a general bus cycle shown in FIG. 18, the cycle start packet is transferred from the cycle master to each node at the start of a cycle #m. Upon receiving the cycle start packet, each node performs time adjustment. After waiting for the predetermined idle period (isochronous gap), the node which is going to execute the isochronous transfer enters arbitration and then starts the packet transfer. In FIG. 18, channels e, s and k are transferred by isochronous transfer in sequence.
The above process from the arbitration to the packet transfer is repeated in times corresponding to the number of channels given. Subsequently, when the isochronous transfer in the cycle #m is completed, the asynchronous transfer can be started.
Upon the idle time reaching the end of the subaction gap necessary for starting the asynchronous transfer, the node which is going to execute the asynchronous transfer determines that it may enter the arbitration.
However, the asynchronous transfer can be started only when the subaction gap necessary for starting the asynchronous transfer is obtained during a period from the end of the isochronous transfer to the time (CYCLE SYNCH) at which the next cycle start packet is transferred.
In the cycle #m shown in FIG. 18, three channels are first transferred by isochronous transfer, and two packets (packets 1 and 2) are then transferred by asynchronous transfer (including ACK). The transfer in the cycle #m is ended by sending the asynchronous packet 2 because the time (CYCLE SYNCH) to start the next cycle (m+1) is reached after the asynchronous packet 2.
If the time (CYCLE SYNCH) to transmit the next cycle start packet is reached during the operation of the asynchronous or isochronous transfer, the operation is not forcibly suspended, and the cycle start packet for the next cycle is transmitted after waiting for the idle period subsequent to the pending transfer. In other words, if one cycle continues over 125 xcexcs, it is assumed that the next cycle is contracted from the reference period, i.e., 125 xcexcs, by an amount corresponding to the extension of the preceding cycle. Thus the isochronous cycle can be extended and contracted from the reference period of 125 xcexcs.
In order to maintain real-time transfer, however, the asynchronous transfer is always executed in each cycle if necessary. Due to contraction of the cycle time, the asynchronous transfer may be delayed to the next or subsequent cycle.
The above-described process, including such delay information, is managed by the cycle master.
(WWID (World Wide Unique ID))
According to the 1394 serial bus standards, each node incorporates a configuration ROM for expressing its own functions. FIG. 23 shows a part of the configuration ROM.
Referring to FIG. 23, IDs stored in addresses from FFFFF000040C to FFFFF0000410 comprise a vendor ID 2301 of three bytes and chip IDs 2302, 2303 of five bytes. The vendor ID 2301 is an ID acquired by each vendor as a result from applying for the ID from the IEEE, and contains information indicating, e.g., the name of each vendor. The chip IDs 2302, 2303 are allocated at the vendor""s discretion, and are set to a unique ID for each node. There is hence no ID that is the same as the unique ID (2301-2303) of each node.
The above ID (2301-2303) uniquely allocated for each node is called a World Wide Unique ID (referred to a WWUID hereinafter). Each node on a network constructed with the IEEE 1394 serial bus can know the WWUID by reading the IDs at the addresses from FFFFF000040C to FFFFF0000410 in the configuration ROM of a device which is connected to the bus and has an objective node ID.
The IEEE 1394 serial bus has been described above.
As seen from the above description, the IEEE 1394 I/F has various advantages overcoming the inconveniences experienced in conventional data communication systems. In particular, since the IEEE 1394 I/F can transfer a large amount of data, such as image information, at a high speed along with device control data, using the IEEE 1394 I/F makes it possible to construct a new system wherein an imaging device represented by a video camera is controlled by a PC.
Stated otherwise, the present invention intends to construct a system for controlling a camera control unit originally incorporated in an imaging device, by outputting an operation command or instructing some change of a control method from a PC to thereby permit the imaging device to execute an operation different from that commanded by remote control, or some change of the control method executed by the camera control unit originally incorporated in the imaging device, to thereby carry out an operation to perform a special operation in the video camera being controlled.
FIG. 24 shows an example of screen display of an application (referred to a camera setting application) for operating and controlling a camera from a PC as mentioned above.
The camera setting application operates in a condition where a PC 2501 and a video camera 2505 are connected to each other by a 1394 serial bus 2504, as shown in FIG. 25. The user can freely change the setting of various control parameters in the video camera 2505, such as tint, color gain, f-stop number and shutter speed, by using a keyboard 2503 or a pointing device 2502. For example, when a shutter speed changing lever 2405 is moved to the left or right with the pointing device 2502, a setting value corresponding to the lever position is transmitted from the PC 2501 to the video camera 2505 via the 1394 serial bus 2504. The video camera 2505 can actually change the shutter speed by storing the setting value at a predetermined location in an internal memory.
Here, the 1394 serial bus can transmit and receive both image data and a command group (CTS) for controlling a partner device at the same time. Therefore, when the video camera 2505 transmits image data to the PC 2501, the user can confirm the camera image on a screen of the PC 2501 in real time. A camera image display window 2401 on the camera setting application screen of FIG. 25 is a screen for displaying in real time an image transmitted from the video camera 2505. In other words, by changing the setting of control parameters of the video camera from the PC in such a manner as described above, the user can immediately confirm a result of the change on the camera image display window 2401.
The illustrated conventional example includes several kinds of camera control parameters which are changeable, but there exist many other parameters which can be set from the PC. FIG. 28 shows examples of commands transmitted from the PC for changing the parameters.
Although the camera setting application carries out the above-described function in the condition where the video camera 2505 and the PC 2501 are connected to each other as shown in FIG. 25, there is a simulation mode in the camera setting application. The simulation mode means such a function that the PC simulates an optimum image by itself alone by changing the setting of camera control parameters with respect to an original image picked up by the camera.
The simulation mode will be briefly described below with reference to FIGS. 26 and 27.
FIG. 26 shows an example in which a sunset scene shot by the user is displayed on the camera image display window 2401 in the simulation mode. An operating mode 2407 of the camera setting application is selected to xe2x80x9cSIMULATIONxe2x80x9d by the pointing device. In this condition, the camera setting application stops the PC from taking in image information from the video camera, and an image, which is simulated as described later, is continuously displayed on the camera image display window 2401.
In the case of shooting the setting sun, the user generally desires to produce an image rich in red. With usual auto-setting of the video camera, however, an auto-white balancing function is operated to suppress a component of red color to become as close as possible to white. Accordingly, red color of the taken-in image is lightened, and a sunset scene cannot be shot as desired. Then, the user changes the setting of camera control parameters on the camera setting application screen, such as tint 2402, color gain 2403, f-stop number 2404, shutter speed 2405, and quakeproof on/off 2406, by using the pointing device or the keyboard on the PC. For example, the tint 2402 is set nearer to the blue side in an initial image, but the tint setting is changed to come closer to the red side for emphasizing the red color of the sunset. Corresponding to the lever position of the tint 2402 to be changed, the camera setting application changes the camera control parameters so that the same image on the camera image display window 2401 has a tint corresponding to the change in the parameter. Thus, the image displayed on the camera image display window 2401 has the tint emphasized in red. Likewise, the user can change the setting of the other parameters, such as the color gain 2403 and the f-stop number 2404, in accordance with his/her preference while confirming a simulated image on the camera image display window 2401. Finally, the user can obtain the optimum camera setting as shown in FIG. 27.
Further, the optimum camera setting can be stored as a file in the memory within the PC by manipulating a file menu 2408 on a task bar. The stored setting can be transmitted to the video camera when it is connected to the PC again, enabling the video camera to be set to xe2x80x9can optimum condition for shooting the sunsetxe2x80x9d.
The above-described related art however has the following problem. Even with the video camera being not connected, the optimum camera setting parameters can be decided based on simulation. Accordingly, when the video camera is connected to the PC later, there occurs a discrepancy between setting values in the video camera and values changed on the PC. As a result, the operation of the camera setting application and the actual operation of the video camera can not be matched with each other.
The present invention has been made in the view of the problem set forth above, and its object is, in a camera setting system wherein a control device, such as a PC, and a video camera are connected to each other, to automatically avoid a mismatch between setting values on the PC side and camera setting values in the video camera which occurs immediately after the connection therebetween, immediately after the PC and the video camera are connected again.
Another object of the present invention is, in a camera setting system wherein a control device, such as a PC, and a video camera are connected to each other, and particularly in a camera setting system having a simulation function, to automatically avoid a mismatch between setting values on the PC side, which have been changed upon execution of simulation, and unchanged setting values in the video camera, immediately after the PC and the video camera are connected again.
Still another object of the present invention is, in a camera setting system wherein a control device, such as a PC, and a plurality of video cameras are connected to each other, to avoid a mismatch between setting values on the PC side, which correspond to a particular one of the video cameras, and camera setting values in the particular video camera, immediately after the connection therebetween.
Still another object of the present invention is, in a camera setting system wherein a control device, such as a PC, and a plurality of video cameras are connected to each other, and particularly in a camera setting system having a simulation function, to automatically avoid a mismatch between setting values on the PC side, which have been changed upon execution of simulation, and unchanged setting values in a particular one of the video cameras, immediately after the PC and the particular video camera are connected again.
Still another object of the present invention is, in a camera setting system wherein a control device, such as a PC, and a plurality of video cameras are connected to each other, to surely select a particular one of the video cameras by utilizing IDs specific to the video cameras, and to automatically avoid a mismatch between setting values on the PC side, which have been changed and correspond to the selected video camera, and camera setting values in the selected video camera.
Still another object of the present invention is, in a camera setting system wherein a control device, such as a PC, and a video camera are connected to each other, to avoid a mismatch between a display of setting values on the PC side and camera setting values in the video camera, immediately after the connection therebetween.
Still another object of the present invention is, in a camera setting system wherein a control device, such as a PC, and a plurality of video cameras are connected to each other, to avoid a mismatch between a display of setting values on the PC side, which correspond to particular one of the video cameras, and camera setting values in the particular video camera, immediately after the connection therebetween.
Still another object of the present invention is, in a camera setting system wherein a control device, such as a PC, and a plurality of video cameras are connected to each other, to surely select a particular one of the video cameras by utilizing IDs specific to the video cameras, and to avoid a mismatch between a display of setting values on the PC side, which correspond to the particular video camera, and camera setting values in the selected video camera, immediately after the connection therebetween.
Still another object of the present invention is to produce an alarm display when setting values on the PC side (which correspond to a particular video camera) differ from camera setting values in a selected video camera.
To solve the above-described problem and to achieve the above-mentioned objects, the present invention provides an imaging device system comprising a control device having a first data communication node, and an imaging device having a second data communication node connected to the first data communication node in a mutually communicable manner. The imaging device includes a controlled unit capable of being externally controlled in accordance with information inputted from the second data communication node. The control device comprises a control unit for outputting the information to control the imaging device from the first data communication node, a storage unit for storing at least one or more preset imaging device control conditions, and a control condition changing unit for changing the imaging device control conditions stored in the storage unit. A detecting unit is provided for detecting whether the control device and the imaging device are connected, and an output unit is started up in response to a detection signal from the detecting unit for reading the imaging device control conditions stored in the storage unit and outputting the read control conditions from the first data communication node.
In the above imaging device system according to the present invention, the control device may further comprise a display unit for displaying an image corresponding to the imaging device control conditions changed by the control condition changing unit.
Also, the present invention provides an imaging device system comprising a control device having a first data communication node, and a plurality of imaging devices having second to N-th (N is an integer not less than three) data communication nodes connected to the first data communication node in a mutually communicable manner. The plurality of imaging devices include controlled units capable of being externally controlled in accordance with information inputted respectively from the second to N-th data communication nodes. The control device comprises a control unit for outputting the information to control the plurality of imaging devices individually from the first data communication node, a first storage unit for storing at least one or more imaging device control conditions preset corresponding to each of the plurality of imaging devices, and a selecting unit for selecting one among the plurality of imaging devices which is to be controlled. A control condition changing unit is provided for changing the imaging device control conditions stored in the first storage unit and corresponding to the imaging device selected by the selecting unit. A detecting unit is provided for detecting whether the control device and the selected imaging device are connected, and an output unit started up in response to a detection signal from the detecting unit for reading the imaging device control conditions changed by the control condition changing unit and outputting the read control conditions from the first data communication node.
In the above imaging device system according to the present invention, the control device may further comprise a display unit for displaying an image corresponding to the imaging device control conditions changed by the control condition changing unit.
In the above imaging device system according to the present invention, the selecting unit may select a particular one among the plurality of connected imaging devices by outputting an ID number specific to the particular imaging device from the first data communication node.
Further, the present invention provides an imaging device system comprising a control device having a first data communication node, and an imaging device having a second data communication node connected to the first data communication node in a mutually communicable manner. The imaging device comprises a controlled unit capable of being externally set to a particular state in accordance with a command inputted from the second data communication node, and a transmitting unit capable of externally transmitting the particular set state. The control device comprises a control unit for outputting, from the first data communication node, a command to set the imaging device to a particular state and a command to read a particular setting value in the imaging device, a storage unit for storing at least one or more preset imaging device setting values, and a display unit for displaying the stored setting values. A detecting unit is provided for detecting whether the control device and the imaging device are connected. An output unit is started up in response to a detection signal from the detecting unit and outputs the command to read the particular setting value in the imaging device from the first data communication node. An input unit is provided for inputting, into the storage unit, the particular setting value read in accordance with the command outputted from the output unit.
Still further, the present invention provides an imaging device system comprising a control device having a first data communication node, and a plurality of imaging devices having second to N-th (N is an integer not less than three) data communication nodes connected to the first data communication node in a mutually communicable manner. The plurality of imaging devices includes controlled units capable of being externally controlled to set the plurality of imaging devices to particular states in accordance with commands inputted respectively from the second to N-th data communication nodes. A transmitting unit is provided that is capable of externally transmitting the particular set states. The control device comprises a control unit for outputting, from the first data communication node, commands to individually set the plurality of imaging devices to particular states, and commands to individually read particular setting values in the plurality of imaging devices. A storage unit is provided for storing at least one or more preset imaging device setting values corresponding to each of the plurality of imaging devices. A selecting unit is provided for selecting one among the plurality of imaging devices which is to be controlled. A display unit is provided for displaying the stored setting values corresponding to the imaging device selected in the selecting step. A detecting unit is provided for detecting whether the control device and the selected imaging device are connected. An output unit is started up in response to a detection signal from the detecting unit, for outputting the command to read the particular setting value in the selected imaging device from the first data communication node. An input unit is provided for inputting, in an area of the storage unit corresponding to the selected imaging device, the particular setting value read in accordance with the command outputted from the output unit.
In the above imaging device system according to the present invention, the selecting unit may select a particular one among the plurality of connected imaging devices by outputting an ID number specific to the particular imaging device from the first data communication node.
The above imaging device system according to the present invention may further comprise a comparing unit for comparing the read particular setting value in the imaging device with the corresponding imaging device setting value stored in the storage unit before reading the particular setting value, and an alarm display unit started up by the comparing unit.
Moreover, the present invention provides a control method for an imaging device system comprising a control device having a first data communication node, and an imaging device having a second data communication node connected to the first data communication node in a mutually communicable manner. The control method comprises a control step of outputting information to control the imaging device from the second data communication node, a storing step of storing at least one or more preset imaging device control conditions, and a control condition changing step of changing the imaging device control conditions stored in the storing step. A detecting step is provided for detecting whether the control device and the imaging device are connected, and an output step is provided for, in accordance with a detection result in the detecting step, reading the imaging device control conditions stored in the storing step and outputting the read control conditions from the first data communication node.
Further, the present invention provides a control method for an imaging device system comprising a control device having a first data communication node, and a plurality of imaging devices having second to N-th (N is an integer not less than three) data communication nodes connected to the first data communication node in a mutually communicable manner. The control method comprises a control step of outputting information to control the plurality of imaging devices individually from the first data communication node, a first storing step of storing at least one or more imaging device control conditions preset corresponding to each of the plurality of imaging devices, and a selecting step of selecting one among the plurality of imaging devices which is to be controlled. A control condition changing step is provided for changing the imaging device control conditions corresponding to the imaging device selected in the selecting step. A detecting step is also provided for detecting whether the control device and the selected imaging device are connected, and an output step is provided for, in accordance with a detection result in the detecting step, reading the imaging device control conditions changed in the control condition changing step and outputting the read control conditions from the first data communication node.
Still further, the present invention provides a control method for an imaging device system comprising a control device having a first data communication node, and an imaging device having a second data communication node connected to the first data communication node in a mutually communicable manner. The control method comprises a control step of outputting, from the first data communication node, a command to set the imaging device to a particular state and a command to read a particular setting value in the imaging device. A first storing step is provided for storing at least one or more preset imaging device setting values. A displaying step is also provided for displaying the stored setting values, and a detecting step is provided for detecting whether the control device and the imaging device are connected. An output step is provided for, in accordance with a detection result in the detecting step, outputting the command to read the particular setting value in the imaging device from the first data communication node. A second storing step is provided for storing the particular setting value read in accordance with the command outputted in the output step.
Still further, the present invention provides a control method for an imaging device system comprising a control device having a first data communication node, and a plurality of imaging devices having second to N-th (N is an integer not less than three) data communication nodes connected to the first data communication node in a mutually communicable manner. The control method comprises a control step of outputting, from the first data communication node, commands to individually set the plurality of imaging devices to particular states, and commands to individually read particular setting values in the plurality of imaging devices. A first storing step is provided for storing at least one or more preset imaging device setting values corresponding to each of the plurality of imaging devices, and a selecting step is provided for selecting one among the plurality of imaging devices which is to be controlled. A displaying step is provided for displaying the stored setting values corresponding to the imaging device selected in the selecting step, and a detecting step is provided for detecting whether the control device and the selected imaging device are connected. An output step is provided for, in accordance with a detection result in the detecting step, outputting the command to read the particular setting value in the selected imaging device from the first data communication node. A second storing step is provided for storing, corresponding to the selected imaging device, the particular setting value read in accordance with the command outputted in the output step.
Moreover, the present invention provides a storage medium storing a control program for controlling an imaging device system comprising a control device having a first data communication node, and an imaging device having a second data communication node connected to the first data communication node in a mutually communicable manner. The control program comprises code for a control step of outputting information to control the imaging device from the second data communication node, code for a storing step of storing at least one or more preset imaging device control conditions, and code for a control condition changing step of changing the imaging device control conditions stored in the storing step. Code is also provided for a detecting step of detecting whether the control device and the imaging device are connected. And code is provided for an output step of, in accordance with a detection result in the detecting step, reading the imaging device control conditions stored in the storing step and outputting the read control conditions from the first data communication node.
Further, the present invention provides a storage medium storing a control program for controlling an imaging device system comprising a control device having a first data communication node, and a plurality of imaging devices having second to N-th (N is an integer not less than three) data communication nodes connected to the first data communication node in a mutually communicable manner. The control program comprises code for a control step of outputting information to control the plurality of imaging devices individually from the first data communication node, and code for a first storing step of storing at least one or more imaging device control conditions preset corresponding to each of the plurality of imaging devices. Code is provided for a selecting step of selecting one among the plurality of imaging devices which is to be controlled. Code is also provided for a control condition changing step of changing the imaging device control conditions corresponding to the imaging device selected in the selecting step. Code is provided for a detecting step of detecting whether the control device and the selected imaging device are connected. And code is provided for an output step of, in accordance with a detection result in the detecting step, reading the imaging device control conditions changed in the control condition changing step and outputting the read control conditions from the first data communication node.
Still further, the present invention provides a storage medium storing a control program for controlling an imaging device system comprising a control device having a first data communication node, and an imaging device having a second data communication node connected to the first data communication node in a mutually communicable manner. The control program comprises code for a control step of outputting, from the first data communication node, a command to set the imaging device to a particular state, and a command to read a particular setting value in the imaging device. Code is also provided for a first storing step of storing at least one or more preset imaging device setting values. Code is provided for a displaying step of displaying the stored setting values, and code is provided for a detecting step of detecting whether the control device and the imaging device are connected. Code is also provided for an output step of, in accordance with a detection result in the detecting step, outputting the command to read the particular setting value in the imaging device from the first data communication node. And code is provided for a second storing step of storing the particular setting value read in accordance with the command outputted in the output step.
Still further, the present invention provides a storage medium storing a control program for controlling an imaging device system comprising a control device having a first data communication node, and a plurality of imaging devices having second to N-th (N is an integer not less than three) data communication nodes connected to the first data communication node in a mutually communicable manner. The control program comprises code for a control step of outputting, from the first data communication node, commands to individually set the plurality of imaging devices to particular states and commands to individually read particular setting values in the plurality of imaging devices. Code is also provided for a first storing step of storing at least one or more preset imaging device setting values corresponding to each of the plurality of imaging devices. Code is provided for a selecting step of selecting one among the plurality of imaging devices which is to be controlled. Code is also provided for a displaying step of displaying the stored setting values corresponding to the imaging device selected in the selecting step. Code is provided for a detecting step of detecting whether the control device and the selected imaging device are connected, and code is provided for an output step of, in accordance with a detection result in the detecting step, outputting the command to read the particular setting value in the selected imaging device from the first data communication node. And code is provided for a second storing step of storing, corresponding to the selected imaging device, the particular setting value read in accordance with the command outputted in the output step.
Also, the present invention provides an imaging device for use in any of the imaging device systems according to the present invention.
Further, the present invention provides a control device for use in any of the imaging device systems according to the present invention.
Still further, the present invention provides a control method implemented in an imaging device for executing the control method for any of the imaging device systems according to the present invention.
Still further, the present invention provides a control method implemented in a control device for executing the control method for any of the imaging device systems according to the present invention.
Moreover, the present invention provides an imaging device system comprising a control device having a first data communication node, and an imaging device having a second data communication node connected to the first data communication node in a mutually communicable manner. When the imaging device and the control device are connected, either imaging device control conditions set on the imaging device side or imaging device control conditions set on the control device side are set to both the imaging device and the control device.
Further, the present invention provides a control method for an imaging device system comprising a control device having a first data communication node, and an imaging device having a second data communication node connected to the first data communication node in a mutually communicable manner. When the imaging device and the control device are connected, either imaging device control conditions set on the imaging device side or imaging device control conditions set on the control device side are set to both the imaging device and the control device.
Still further, the present invention provides a storage medium storing a control program for controlling an imaging device system comprising a control device having a first data communication node, and an imaging device having a second data communication node connected to the first data communication node in a mutually communicable manner. The control program includes code for a step of, when the imaging device and the control device are connected, setting either imaging device control conditions set on the imaging device side or imaging device control conditions set on the control device side to both the imaging device and the control device.

Imaging device system, control method for the system, imaging device, control device, control method for the imaging device, control method for the control device, and storage medium


A method of surveying the condition of an underground conduit by positioning a propelled carriage assembly within the underground conduit. The carriage assembly includes (i) at least one transmitter/receiver unit capable of transmitting a pulsed signal toward at least a portion of an inner wall of the conduit, and (ii) a secondary sensor positioned on the carriage assembly. The data derived from the pulsed signal at a given lateral location within an underground conduit is read as is a secondary sensor condition derived from secondary sensor data taken at the given lateral location. Then it is determined whether the secondary sensor condition indicates a basis for a false void detection by the data derived from the pulsed signal and if the basis for false void detection exists, providing an indication of such basis.

Buried pipe or conduit systems, e.g., sewer and storm water pipes, culverts, tunnels, etc., deteriorate over time under the action of applied and environmental loads. One important aspect of infrastructure management is the availability of accurate inspection data which allows infrastructure decision makers to provide optimal selection and timely deployment of rehabilitation resources. Inaccurate assessment of the structural integrity of buried pipes and structures can result in spending of hundreds of millions of dollars on replacing non-critical infrastructure elements not in need of immediate repair. On the other hand, the collapse of buried structures, loss of service, environmental spills, damage to adjacent infrastructure (e.g., road surfaces), and in some cases injuries and loss of life, can occur when critical infrastructure repairs are not correctly identified and made. Devices and methods for increasing the accuracy of information derived from pipe and conduit inspections will result in significant cost savings for agencies responsible for infrastructure maintenance.

Sensor fusion framework using multiple sensors to assess buried structures

Louisiana Tech University Research Foundation; a Division of Louisiana Tech University Foundation, Inc.


When a program of a certain duration is converted into compressed data (encoded), it is desirable for the total number of data to fit in an available data space, for example, when recorded on an information carrier. More particularly in variable bit rate compression such as a video signal via MPEG-2, this is hard to forecast. For this purpose, a recording device according to the invention comprises a compression unit (22) whose bit rate is influenced by a system controller (45) via a control input (26) during the encoding process in dependence on the remaining part of the vacant data space on the information carrier (1) and the remaining duration of the program. When parameters influencing the bit rate are set in the compression unit (22), the system controller will take the complexity of the program derived during a previously encoded part of the program into account.

Such an encoding device, recording device, method and encoded signal are known from EP-A 0584991. This document discloses a system for encoding video information in digital data for recording a video program having a known duration (such as a film) on a disc, such as a high density optical disc, for example, the so-termed DVD (Digital Video Disc). For this purpose, the system includes a an MPEG like video compression unit arranged for motion compensation, DCT (Discrete Cosine Transform), quantization and variable length coding, as is customary for MPEG. The controller of the compression unit is arranged for controlling the encoding of the video program so as to fit the program within an available data space on the disc. The data space available for storage on the disc is filled by attuning the bitrate of the coded video program to the available data space to achieve a high average picture quality. The target bitrate to be achieved is calculated from the available data space and the time to be recorded. The actual bitrate is monitored and if it deviates from the target bitrate the compression settings are adjusted. In the event of video material with a lot of activity, the applied settings will often result in a higher actual bitrate than the target bitrate. The compression settings will then be adjusted. However in the first part of the recording time with such video material a more than proportional amount of data space will be filled. Therefore an adjustment of the target bitrate during the further recording time will be required.
It is well known to provide structure to perform functions in a controller by programming the controller and to copy structures from the memory of one controller into the memory of another controller to program the other controller. Thus, a programmed controllers illustrated herein provide apparatus for programming another controller.
The above citations are hereby incoporated herein in whole by reference.

This patent is subject to a terminal disclaimer.

Encoding device for encoding a program and recording device


A terminal crimping system for a crimping machine includes an anvil, a movable ram, an image acquisition device, and a display device. The anvil is located in a crimping zone and configured to receive a terminal thereon. The terminal has a wire crimp barrel configured to receive a wire therein. The ram has crimp tooling configured to crimp the wire crimp barrel of the terminal to the wire during a crimp stroke of the ram. The image acquisition device is configured to be mounted on the crimping machine above the crimping zone. The image acquisition device is positioned to acquire an image of the wire within the wire crimp barrel of the terminal in the crimping zone. The display device is configured to display the image.

The subject matter herein relates generally to wire alignment aids in terminal crimping systems.
Electrical terminals may be crimped onto wires by a crimping machine, such as a bench machine or a lead making machine, to form a lead. In a typical crimping operation, a terminal is placed in a crimping zone of the crimping machine and a wire is inserted into a ferrule or barrel of the terminal. Then, a ram of the crimping machine moves toward the wire and terminal along a crimp stroke. The ram pinches or crimps the terminal around the wire, which mechanically and electrically connects the wire to the terminal and forms the lead.
The position and orientation of the wire relative to the terminal in the crimping zone is critical to the overall production performance and efficiency of the crimping machine. For example, production leads have to meet very strict crimp specifications. A wire that is not properly located in either the side-to-side or front-to-back directions relative to the terminal will not meet the crimp specifications. Leads that do not meet crimp specifications are discarded, which wastes time and materials.
Typically, an operator has to make one or more mechanical adjustments to the crimping machine and/or a wire feeder device in order to accurately position the wire relative to the terminal in the crimping zone. However, the wire and the terminal may be of a small scale that makes viewing the wire and terminal, and especially any slight misalignment between the wire and the terminal, difficult to see with the naked eye in order for the operator to determine which adjustments to make. The difficulty of viewing the wire relative to the terminal is further complicated because many crimping machines do not provide an operator with easy access to the working zone where the crimping operation occurs. For example, in automatic lead making machines, multiple wire-handling devices may crowd the working area, and the working sides of the devices may all face a central area of the machine, making it difficult if not impossible for an operator outside of the machine to access and view the crimping zone.
Often, only fine adjustments are needed to separate an accepted lead from a discarded lead. The operator must exercise great care, exceptional vision, and finesse to adjust the crimping machine and/or the wire feeder so that the wire is properly centered relative to the terminal. The inability to view, up close, the wire relative to the terminal may not provide an operator with enough information to make the necessary adjustments in a timely fashion.

Terminal crimping system with wire alignment aid


Differential clamp circuits configured to recirculate the current in one clamp, either low-side clamp or high-side clamp, from one output of a differential signal to the other output of the differential signal are disclosed. Differential clamp circuits described herein may be particularly suitable for providing programmable clamps at differential outputs of an ADC driver and may be particularly beneficial to implement clamps that are symmetrical around an ADC's input common-mode voltage. Some differential clamp circuit described herein may advantageously present a smaller capacitive load at each output, thus reducing bandwidth degradation of the output stage. Furthermore, differential clamp circuits described herein may operate with only one control voltage, making it easier to limit the output excursions symmetrically around the default common-mode voltage.

In certain applications, it is desirable to control the highest and the lowest levels of an input signal. This is referred to, respectively, as "high-side clamping" and "low-side clamping." High-side clamping may be used to limit the input signal to a device to avoid damage. Low-side clamping may be used to set a minimum voltage into a device to ensure proper operation of the device. Clamping also limits the maximum range input signal to a device.
An analog-to-digital converter (ADC) is one type of a device that is typically implemented in combination with clamping of input signals provided thereto. An ADC may be overloaded when an input signal provided thereto exceeds minimum and maximum voltages within the ADC's full-scale range. High-speed ADCs, for example those used as modern pipeline converters, may also overload if common-mode voltages of input signals provided to the ADCs are not maintained in a narrow band (e.g., less than 100 millivolts (mV)) around the input common-mode voltages of the ADCs. Overload conditions are highly undesirable because, even for high-speed ADCs, it may take several microseconds or even milliseconds before an ADC recovers from the overload, during which time the ADC is not be able to acquire and process input signals even if the input signals are within the full-scale of the ADC. An ADC being temporarily disabled may be absolutely critical in some applications, such as light detection and ranging (LIDAR) systems. For example, if an ADC in a LIDAR receiver signal chain overloads, the LIDAR will be blind to its surroundings until the ADC recovers.
An electronic component configured to perform clamping of input signals provided to an ADC is referred to as an "ADC driver" and may be a key factor in enabling an associated ADC to achieve its desired performance. To that end, first of all, the ADC driver, which is typically operated at a higher supply voltage than the ADC, should ensure that the driver's maximum output never exceeds the ADC's supply to protect to ADC from permanent damage. Second, the ADC driver should condition its outputs as not to overload the ADC. An ADC may be overloaded when the outputs from an ADC driver exceed the minimum and maximum voltages within the ADC's full-scale range. Besides clamping, an ADC driver may perform other signal conditioning functions such as buffering, amplitude scaling, single-ended-to-differential and differential-to-single-ended conversion, common-mode offset adjustment, and filtering, typically aimed to reduce or eliminate the chances of temporarily disabling or permanently destroying the ADC.
A variety of factors can affect the cost, quality and robustness of a clamp circuit included in an ADC driver or any other device where the highest and lowest levels of an output signal may need to be controlled before providing such a signal as an input to another device. Physical constraints such as space/surface area and also regulations can pose further constraints to the requirements or specifications of a clamp circuit, and, thus, trade-off and ingenuity have to be exercised.

Differential clamp circuits with current recirculation

Analog Devices International Unlimited Company