Abstract:
A control apparatus is provided for controlling an image capture apparatus. The control apparatus includes a communication unit for receiving an image captured by the image capture apparatus, and a control unit coupled to the communication unit. The control unit controls a frame setting process for setting a shape, a position, and an area of a frame, and a first command sending process for sending a first command to the image capture apparatus in order to set the frame within the image captured by the image capture apparatus. The first command indicating the shape, the position, and the area set in the frame setting process. The control unit further controls a function selection process for selecting a function to be set in the frame, and a second command sending process for sending a second command to the image capture apparatus. The second command indicating the function selected in the function selection process.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a data communication system, a data communication control method and an electronic apparatus, particularly to a network in which digitized image signals are dealt with. 
   2. Related Background Art 
   Recently, techniques for transmitting digitized animated image signals in real time have been developed. As one of the techniques, there is a high-rate serial bus (hereinafter referred to as 1394 serial bus) in conformity with IEEE (the Institute of Electrical and Electronics Engineers, Inc.) 1394-1995 standards (hereinafter referred to as IEEE 1394 standards). The technique is noted as a communication interface of a camera incorporating type digital video recorder (hereinafter referred to as DVCR) or another AV (Audio/Visual) apparatus. 
   In the IEEE 1394 standards, however, physical, electrical constitution of a connector, two types of most basic data transfer systems, and the like are merely defined, and it is not defined what type of apparatus is used and how the apparatus is constructed to be remote-controlled. Moreover, a type of data to be transmitted, a data format and a communication procedure for the transmittance are also indefinite. 
   Therefore, in the 1394 serial bus, a camera unit equipped in DVCR cannot be remote-operated, so that a user must directly operate a DVCR unit. 
   Furthermore, in the 1394 serial bus, a high-rate image transfer can be performed, but the setting of an image quality for a displayed image of a certain apparatus, or the setting of an image quality for a taken image of a certain apparatus cannot be remote-operated. 
   On the other hand, in the conventional DVCR, auto-focusing or another specific function is only preset for a fixed area on the taken image. Therefore, the user himself cannot set an arbitrary area for the taken image, or cannot select or set a desired function for the area. Furthermore, such operation cannot be performed in a remote manner. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to solve the above-described problems. 
   Another object of the invention is to provide an operation environment to realize various controls and inquiries concerning a taken image of an image pickup unit and a displayed image of a display unit by remote operation in a data communication system, data communication control method and electronic apparatus. 
   In an embodiment of the present invention, a method for controlling an image capture appartus is provided. The method includes the steps of receiving an image captured by the image capture apparatus; setting a shape, a position, and an area of a frame; sending a first command to the image capture apparatus in order to set the frame within the image captured by the image capture apparatus, the first command indicating the shape, the position, and the area set in the frame setting step; selecting a function to be set in the frame; and sending a second command to the image capture apparatus, the second command indicating the function selected in the function selection step. 
   In another embodiment of the present invention, a control apparatus for controlling an image capture appratus is provided. The control apparatus includes a communication unit for receiving an image captured by the image capture apparatus, and a control unit coupled to the communication unit. The control unit controls a frame setting process for setting a shape, a position, and an area of a frame, and a first command sending process for sending a first command to the image capture apparatus in order to set the frame within the image captured by the image capture apparatus. The first command indicating the shape, the position, and the area set in the frame setting process. The control unit further controls a function selection process for selecting a function to be set in the frame, and a second command sending process for sending a second command to the image capture apparatus. The second command indicating the function selected in the function selection process. 
   In a further embodiment of the present invention, a storage medium which stores software for executing a method for controlling an image capture apparatus is provided. The method includes the steps of receiving an image captured by the image capture apparatus; setting a shape, a position, and an area of a frame; sending a first command to the image capture apparatus in order to set the frame within the image captured by the image capture apparatus, the first command indicating the shape, the position, and the area set in the frame setting step; selecting a function to be set in the frame; and sending a second command to the image capture apparatus, the second command indicating the function selected in the function selection step. 
   Still other objects of the present invention, and the advantages thereof, will become fully apparent from the following detailed description of the embodiments. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram showing a constitution of a data communication system of a first embodiment. 
       FIG. 2  is a view showing one example of a graphical user interface of the first embodiment. 
       FIGS. 3A ,  3 B and  3 C are views showing types of commands (control command, status command, notify command). 
       FIG. 4  is an explanatory view of a communication procedure based on FCP. 
       FIGS. 5A and 5B  are views showing data formats of CTS commands of the first embodiment. 
       FIG. 6  is a view showing the data format of FRAME COMMAND of the first embodiment. 
       FIGS. 7A and 7B  are views showing data formats of CTS responses of the first embodiment. 
       FIG. 8  is a view showing a procedure for inquiring the number of frames. 
       FIG. 9  is a view showing CTS command for inquiring the number of frames. 
       FIG. 10  is a view showing CTS response for the inquiry of the number of frames. 
       FIG. 11  is a view showing a procedure for setting various frames. 
       FIG. 12  is a view showing CTS command for setting a rectangular frame. 
       FIG. 13  is a view showing CTS command for setting a circular frame. 
       FIG. 14  is a view showing CTS command for setting a polygonal frame. 
       FIG. 15  is a view showing CTS command for setting a pixel frame. 
       FIG. 16  is a view showing a procedure for inquiring a frame area. 
       FIG. 17  is a view showing CTS command for inquiring the frame area. 
       FIG. 18  is a view showing a procedure for instructing displaying/not-displaying of a selected frame. 
       FIG. 19  is a view showing CTS command for instructing the displaying/not-displaying of the selected frame. 
       FIG. 20  is a view showing a procedure for controlling a function of the selected frame. 
       FIG. 21  is a view showing CTS command for controlling the function of the selected frame. 
       FIG. 22  is a view showing one example of a function which can be controlled by CTS command. 
       FIG. 23  is a view showing a procedure for inquiring a function of the selected frame. 
       FIG. 24  is a view showing CTS command for inquiring the function of the selected frame. 
       FIG. 25  which is comprised of  FIGS. 25A and 25B  are block diagrams showing a constitution of a data communication system of a second embodiment. 
       FIG. 26  is a view showing a packet format of Asynchronous packet. 
       FIGS. 27A and 27B  are views showing data formats of CTS command and CTS response of the second embodiment. 
       FIG. 28  is a view showing a data format of INPUT SIGNAL MODE CONTROL COMMAND of the second embodiment. 
       FIG. 29  is a view showing one example of a graphical user interface of the second embodiment. 
       FIG. 30  is a view showing a procedure for remote-controlling a displayed image. 
       FIG. 31  is a view showing a procedure for remote-controlling a taken image. 
       FIG. 32  is a view showing a communication method for transferring moving image data and a communication method for transferring CTS command, in the embodiment. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The preferred embodiments of the present invention will now be described in detail hereinafter with reference to the accompanying drawings. 
   First Embodiment 
   In a first embodiment, an operation environment will be described in which a network for realizing a real-time data communication of IEEE 1394 serial bus or the like is connected to a target having a camera unit and a controller for remote-operating the target, and a taken image of the camera unit is remote-operated while a controller display screen is being observed. 
     FIG. 1  is a block diagram showing a constitution of a data communication system of the first embodiment. 
   In  FIG. 1 , a camera incorporating type digital video recorder (hereinafter referred to as DVCR)  10  is a target of the present embodiment, and a personal computer (hereinafter referred to as PC)  20  is a controller of the embodiment. Numeral  30  denotes a communication cable in conformity with IEEE 1394 standards. Here, each of DVCR  10  and PC  20  is provided with a digital interface (hereinafter referred to as 1394 interface)  40  in conformity with IEEE 1394 standards. When apparatuses are interconnected using the communication cable  30 , a bus type network is constituted to realize a high-rate serial data communication. 
   The DVCR  10  of  FIG. 1  is provided with a camera sub-unit  11  for generating an image signal of a predetermined format from an optical image of a subject. An animated image taken by the camera sub-unit  11  of DVCR  10  is transferred in real time using Isochronous transfer system based on IEEE 1394 standards. Moreover, a control command asynchronously transferred between DVCR  10  and PC  20  is transferred using Asynchronous transfer system based on IEEE 1394 standards. 
   Here, Isochronous transfer system is a communication system which assures the transfer of a constant amount of data for each predetermined communication cycle (one communication cycle is nearly 125 μs) and which is suitable for a real-time communication of animated images, voice and the like as shown in  3202  and  3203  of  FIG. 32 . Also, Isochronous transfer system is a broadcast communication which does not specify communication destinations. Each device manages Isochronous data outputted by using channel number (chA, chB shown in  FIG. 32 ) assigned to the device and a communication band. Moreover, Asynchronous transfer system is a communication system which becomes effective when the control command, file data and the like are asynchronously transferred as required as shown in  3204  and  3206  of  FIG. 32 . Further, there are a one-on-one communication specifying the communication destination and the broadcast communication not specifying the communication destination in Asynchronous transfer system. Though a receiving node returns acknowledgment (ack  3105 ,  3107  in  FIG. 31 ) in the one-on-one communication, the receiving node does not return the acknowledgment in the broadcast communication. CTS command and CTS response described later use the one-on-one command. Here, Isochronous transfer system and Asynchronous transfer system can be mixed in a time division manner, and in one communication cycle period, Isochronous transfer system has a higher priority than Asynchronous transfer system because an idle term (Isochronous gap in  FIG. 31 ) in which the Isochronous transfer system is executed is set shorter than an idle term (Subaction gap in  FIG. 31 ) in which the Asynchronous transfer system is executed. Accordingly, the Isochronous transfer system is executed subsequent to CSP (Cycle Start Packet)  3101  transferred initially in each communication cycle, prior to the Asynchronous transfer system. By the function, animated images, voices and other information signals having real-time properties can be transmitted without being interrupted in the data communication system of the embodiment. 
   As described above, in the embodiment, since the devices are interconnected via the 1394 interface, communication data of each device can be communicated serially and bidirectionally. Therefore, as compared with the conventional parallel communication, the cost of the entire system can be reduced, and a higher-rate communication can be realized. 
   In the PC  20  of  FIG. 1 , numeral  21  denotes a control unit,  22  denotes a monitor,  23  denotes an operation unit constituted of a mouse, keyboard and the like, and  24  denotes a hard disc or another storage medium. In the storage medium  24 , an application for controlling the camera sub-unit  11  the target has is stored as a program code. The control unit  21  reads the program code from the storage medium  24 , and starts the application to control a display screen of the monitor  22  and the communication with DVCR  10  in accordance with the operation of the operation unit  23 . 
     FIG. 2  is a view showing one example of the display screen of the monitor  22  provided in the PC  20 . Additionally, the display screen of the monitor  22  is prepared based on the application processed by the control unit  21 . 
   In  FIG. 2 , numeral  201  denotes a preview screen on which a taken image isochronously transferred from the DVCR  10  is displayed in an animated manner. 
   Moreover, in  FIG. 2 , numeral  202  denotes Wide button for moving a digital zoom of DVCR  10  in a wide direction,  203  denotes Tele button for moving the digital zoom of DVCR  10  in a tele-direction,  204  denotes Near button for moving a focus of DVCR  10  in a near direction,  205  denotes Far button for moving the focus of DVCR  10  in a far direction, and  206  denotes a control button for setting an area (hereinafter referred to as the frame) having various shapes on the taken image of the DVCR  10 . The buttons  202  to  206  are indicated with icons on the screen. 
   Furthermore, in  FIG. 2 , numeral  2061  denotes a control button for selecting a desired frame from frames which have been set,  2062  denotes a control button for setting a frame having a rectangular shape (hereinafter referred to as the rectangular frame) on the screen of the taken image,  2063  denotes a control button for setting a frame having a circular shape (hereinafter referred to as the circular frame),  2064  denotes a control button for setting a frame having a polygonal shape (hereinafter referred to as the polygonal frame), and  2065  denotes a control button for setting a pixel unit frame (hereinafter referred to as the pixel frame). 
   Additionally, in  FIG. 2 , numerals  207  to  210  are frames which are set on the taken image screen using the control button  206 , and  211  denotes a menu window for performing the setting, or inquiring of various functions for the selected frame. 
   In  FIG. 2 , when the buttons  202  to  205  are operated by the user, the PC  20  asynchronously transfers to the DVCR  10  a control command corresponding to an operation result. The camera sub-unit  11  of DVCR  10  controls its operation in accordance with a content of the received control command.  FIG. 3A  shows one example of a control command for controlling the camera sub-unit  11 . 
   For example, when the buttons  202 ,  203  are operated, PC  20  asynchronously transfers to the DVCR  10  a control command “ZOOM” to control a digital zoom of the camera sub-unit  11 . The DVCR  10  operates the digital zoom of the camera sub-unit  11  in the wide direction or the tele-direction in accordance with the content of the control command. 
   Moreover, in order to know a state of the camera sub-unit  11  of DVCR  10 , PC  20  can asynchronously transfer a status command shown in  FIG. 3B . The PC  20  can know the current state of the camera sub-unit  11  by a response to the status command. 
   For example, when the PC  20  asynchronously transfers the status command “ZOOM” to the DVCR  10 , the DVCR  10  responds to the PC  20  by transmitting position information of the digital zoom of the camera sub-unit  11 . 
   Furthermore, the PC  20  can asynchronously transfer a notify command shown in  FIG. 3C  to the DVCR  10 . When a change occurs in the state designated by the notify command, the camera sub-unit  11  having received the notify command returns the state change to the PC  20 . 
   For example, the PC  20  asynchronously transfers to the DVCR  10  a notify command “ZOOM” to designate a position of digital zoom of the camera sub-unit  11 . In this case, when the digital zoom of the camera sub-unit  11  reaches the position, the DVCR  10  returns a response. 
   In the embodiment, various commands (control command, status command, notify command) shown in  FIG. 3  are transmitted by FCP (Function Control Protocol).  FIG. 4  is an explanatory view of a communication procedure of FCP. In the embodiment, a series of communication procedure shown in  FIG. 4  is hereinafter referred to as a command transaction, and a combination of a command transmitted based on the command transaction and a response to the command is referred to as CTS (Command Transaction Set) command and CTS response. 
   In  FIG. 4 , first, the PC  20  (controller) uses Asynchronous Write transaction based on IEEE 1394 standards to write CTS command  401  into a predetermined memory space (command register) provided in the DVCR  10  (target). The target returns an acknowledgment  402  for the Asynchronous transfer to the controller. 
   Subsequently, the target executes a processing corresponding to the CTS command  401 , and additionally prepares CTS response  403  from an execution result. Thereafter, the target uses Asynchronous Write transaction to write the CTS response  403  into a predetermined memory space (response register) provided in the controller. The controller returns an acknowledgment  404  for the Asynchronous transfer to the target. 
   A packet format of Asynchronous packet for transmitting the CTS command and CTS response of the embodiment will next be described with reference to  FIG. 26 . The packet is transferred to another node by “write transaction” as one of services provided by Asynchronous transfer. The “write transaction” is a service for designating a predetermined area on CSR (Control and Status Register) space of a certain node to write desired data into the area. Here, the CSR space is an address space of 64 bits in conformity with IEEE 1212 standards. Upper 16 bits of the CSR space are used in designation of bus and node (bus ID and node ID), while lower 48 bits are used as an address space of each node. 
   In  FIG. 26 , numeral  2600  denotes Destination_ID field,  2602  denotes a transaction label (hereinafter referred to as tl) field,  2604  denotes a retry code (hereinafter referred to as Rt) field, and  2606  denotes a transaction code (hereinafter referred to as tcode) field. 
   Numeral  2608  denotes a priority (hereinafter referred to as Pri) field,  2610  denotes a source ID (hereinafter referred to as Source_ID) field,  2612  denotes Destination_offset field,  2614  denotes Data_length field,  2616  denotes an extended transaction code (hereinafter referred to as Extended_tcode) field,  2618  denotes a header CRC (hereinafter referred to as Header_CRC) field,  2620  denotes a data field, and  2622  denotes a data CRC (hereinafter referred to as Data_CRC) field. 
   The Asynchronous packet of  FIG. 26  is a data packet having a unit of four bytes (32 bits, hereinafter referred to as quadred). The Destination_ID field  2600  (16 bits) indicates a node ID to designate a destination on the same bus. In the next 6-bit field, the transaction label (tl) field  2602  (6 bits) indicates a tag peculiar to each transaction. In the next 2-bit field, the retry (Rt) code  2604  (2 bits) designates whether the packet makes a retry. 
   The transaction code (tcode)  2606  (4 bits) designates a packet format, and a transaction type to be executed. In the embodiment, for example, the value is “0001 2 ”, requesting for a writing transaction of a data block. The priority (Pri) field  2608  (4 bits) designates a priority. In the embodiment, since the asynchronously transferred packet is used, the value of the field is “0000 2 ”. 
   The Source_ID field  2610  (16 bits) indicates a node ID to designate a transmission end on the same bus. The Destination_offset field  2612  (48 bits) designates lower 48 bits on the CSR space of the destination node. 
   The Data_length field  2614  (16 bits) indicates a length of a data field described later in the unit of byte. In the embodiment the Extended_tcode field  2616  (16 bits) is “0000 16 ”. 
   The above-described Destination_ID field  2600  to the Extended_tcode field  2616  are referred to as a packet header. The Header_CRC field  2618  (32 bits) is used in error detection of the packet header. 
   In the data field  2620  (variable length), CTS command frame and CTS response frame described later are set. The data field  2620  is referred to as the payload. When the data field  2620  is less than a multiple of quadred, “ 0 ” is filled. 
   The Data_CRC field  2622  (32 bits) is used in the error detection of the data field  2620  in the same manner as the Header_CRC field  2618 . 
   Data formats of CTS command transferred to the target from the controller and CTS response transferred to the controller from the target will be described in detail hereinafter with reference to  FIGS. 5 to 7 . 
     FIG. 5A  is a view showing the data format of CTS command asynchronously transferred to the target from the controller. 
   In  FIG. 5A , numeral  504  denotes CTS command. In a ctype field of the CTS command  504 , codes for designating command types are stored.  FIG. 5B  shows examples of the command types stored in the ctype field. 
   Moreover, in the CTS command  504 , data specifying to which sub-unit provided in the target the command corresponds are stored in Subunit_type field and Subunit ID field. In an opcode field and operand [ 0 ] to operand [n] fields, data designating a content of an actual command are stored. 
     FIG. 6  is a view showing one example of the data which are stored in the opcode field and the operand [ 0 ] to operand [n] fields. In  FIG. 6 , the setting of a frame for the taken image of the target, or CTS commands for setting various functions concerning the frame will be described. 
   In  FIG. 6 , a code indicating that the command is a command “FRAME” concerning frame control is stored in the opcode field. In the operand [ 0 ] field, a code indicating a processing performed by the command is stored. In the operand [ 1 ] field, a frame number indicating a frame as an object of the command is stored. In the operand [ 2 ] to operand [n] fields, various parameters for use in the command (e.g., position information of each coordinate to designate a frame range) are stored. 
     FIG. 7A  is a view showing a data format of CTS response asynchronously transferred to the controller from the target. 
   In  FIG. 7A , a code designating a response type is stored in a response field.  FIG. 7B  shows examples of response types stored in the response field. 
   Moreover, in  FIG. 7A , data specifying from which sub-unit provided in the target the response is transferred are stored in Subunit_type field and Subunit ID field. In the opcode field and the operand [ 0 ] to operand [n] fields, data designating a content of an actual response are stored. 
   A procedure will be described hereinafter in which the controller uses the CTS commands shown in  FIG. 5  and the CTS responses shown in  FIG. 7  to set the frame for the taken image of the target, set various functions for the inquiry or the frame and to remote-operate the inquiry. 
   (1) Inquiry of the Number of Frames 
   In the embodiment, the application of PC  20  can inquire of the camera sub-unit  11  about the number of frames which can be set in the taken image of the camera sub-unit  11 . A procedure for inquiring the number of frames will be described hereinafter with reference to  FIG. 8 . 
   In the PC  20 , the user starts the application to display a screen on the monitor  22  as shown in  FIG. 2  ( 801 ). 
   After the application is started, the user uses the operation unit  23  to operate the menu window  211 , and instructs the inquiry of the number of frames which can be set ( 802 ). 
   After the user&#39;s instruction input is confirmed, the PC  20  prepares CTS command to inquire the number of frames ( 803 ). In this case, the CTS command prepared by the PC  20  is shown in  FIG. 9 . 
   In  FIG. 9 , in a ctype field  901  is set “Status” which indicates that the command is a status command to inquire the state of the camera sub-unit  11 . Data specifying the camera sub-unit  11  of DVCR  10  are stored in Subunit_type field  902  and Subunit ID field  903 . 
   Moreover, in  FIG. 9 , a code indicating a command “FRAME” concerning the frame control is set in an opcode field  904 . In an operand [ 0 ] field  905  is set a command “Max Frame” to inquire the maximum number of frames which can be set in the camera sub-unit  11 . Dummy data is set in an operand [ 1 ] field  906 . 
   After the CTS command of  FIG. 9  is prepared, the PC  20  sets the CTS command in Asynchronous packet shown in  FIG. 26 , and transfers the packet to the camera sub-unit  11  ( 804 ). 
   After receiving the above-described CTS command, the camera sub-unit  11  returns an acknowledgment to the PC  20  ( 805 ). 
   Moreover, the camera sub-unit  11  executes a processing corresponding to the received CTS command ( 806 ), and additionally prepares CTS response corresponding to the CTS command ( 807 ). In this case, the CTS response prepared by the camera sub-unit  11  is shown in  FIG. 10 . 
   In  FIG. 10 , “Stable” is set in a response field  1001 . Data specifying the camera sub-unit  11  of DVCR  10  are stored in Subunit_type field  1002  and Subunit ID field  1003 . 
   Moreover, in  FIG. 10 , the same codes “FRAME” and “Max Frame” as the CTS commands transferred from the PC  20  are set in an opcode field  1004  and operand [ 0 ] field  1005 . The maximum number of frames which can be set in the camera sub-unit  11  is set in an operand [ 1 ] field  1006 . 
   After the CTS responses of  FIG. 10  are prepared, the camera sub-unit  11  sets the CTS responses in Asynchronous packet shown in  FIG. 26 , and transfers the packet to the PC  20  ( 808 ). 
   After receiving the above-described CTS response, the PC  20  returns an acknowledgment to the camera sub-unit  11  ( 809 ). Thereafter, the PC  20  visually displays the maximum number of frames included in the CTS response on the monitor  22  ( 810 ). 
   By the above-described procedure, the PC  20  can confirm the maximum number of frames which can set in the taken image of the camera sub-unit  11 , and can additionally control the number of frames which can be set in the camera sub-unit  11  by the application of PC  20 . 
   (2) Setting of Frame 
   In the embodiment, the application of the PC  20  can set a plurality of types of frames in the taken image of the camera sub-unit  11 . A procedure for setting various frames will be described hereinafter with reference to  FIG. 11 . 
   (2-1) Setting of Rectangular Frame 
   In the PC  20 , the user starts the application to display a screen on the monitor  22  as shown in  FIG. 2  ( 1101 ). 
   After the application is started, the user uses the operation unit  23  to operate the control button  2062 , and selects a rectangular frame setting mode from a plurality of modes ( 1102 ). 
   In the rectangular frame setting mode, the user operates the operation unit  23 , and sets a start point of the rectangular frame for the taken image on the preview screen  201 . Subsequently, the user operates the operation unit  23  to set an end point of the rectangular frame. Thereby, a rectangular area with the start and end points being diagonal is determined as in the frame  207  of  FIG. 2  ( 1103 ). 
   After the rectangular frame is set by the application, the PC  20  prepares CTS command to set the rectangular frame ( 1104 ), and asynchronously transfers the CTS command to the camera sub-unit  11  ( 1105 ). In this case, the CTS command prepared in the PC  20  will be described with reference to  FIG. 12 . 
   In  FIG. 12 , in a ctype field  1201  is set “Control” which indicates that the command is a control command to control the camera sub-unit  11 . Data specifying the camera sub-unit  11  of DVCR  10  are stored in Subunit_type field  1202  and Subunit ID field  1203 . 
   Moreover, in  FIG. 12 , a code indicating a command “FRAME” concerning the frame control is set in an opcode field  1204 . A code indicating an area setting command “Area Set” is set in an operand [ 0 ] field  1205 . A frame number “Frame Number” arbitrarily set on the application is set in an operand [ 1 ] field  1206 . 
   Furthermore, in  FIG. 12 , data indicating a frame type “Frame Type” is set in an operand [ 2 ] field. In an operand [ 3 ] field a value of X coordinate of the start point of the rectangular frame “X position of left top” is set, and in an operand [ 4 ] field a value of Y coordinate of the start point of the rectangular frame “Y position of left top” is set. In an operand [ 5 ] field a value of X coordinate of the end point of the rectangular frame “X position of right bottom” is set, and in an operand [ 6 ] field a value of Y coordinate of the end point of the rectangular frame “Y position of right bottom” is set. 
   After receiving the above-described CTS command, the camera sub-unit  11  returns an acknowledgment to the PC  20  ( 1106 ). 
   Moreover, the camera sub-unit  11  executes a processing corresponding to the received CTS command ( 1107 ), and additionally prepares CTS response corresponding to the CTS command ( 1108 ). 
   In this case, when the camera sub-unit  11  does not correspond to “Frame Number” and “Frame Type” designated by the CTS command, the DVCR  10  prepares CTS response by setting a response type “Rejected” or “Not Implemented” to the response field. Furthermore, when the camera sub-unit  11  corresponds to “Frame Number” and “Frame Type” designated by the CTS command, the DVCR  10  prepares CTS response by setting a response type “Accepted” to the response field. 
   Moreover, the camera sub-unit  11  stores the data specifying the sub-unit provided in the target in the Subunit_type field and Subunit ID field of the CTS response. In the opcode field and the operand [ 0 ] to operand [n] fields, the same values as those set in the CTS command are set, respectively. 
   After preparing the CTS response, the camera sub-unit  11  sets the CTS response in Asynchronous packet shown in  FIG. 26 , and transfers the packet to the PC  20  ( 1109 ). The PC  20  returns an acknowledgment of the CTS response to the camera sub-unit  11  ( 1110 ). 
   Subsequently, the PC  20  visually displays on the monitor  22  that the designated rectangular frame is set in the camera sub-unit  11  ( 1111 ). 
   By the above-described communication procedure, the application of the PC  20  can set a rectangular frame area for the taken image of the camera sub-unit  11 . 
   (2-2) Setting of Circular Frame 
   In the PC  20 , the user starts the application to display a screen on the monitor  22  as shown in  FIG. 2  ( 1101 ). 
   After the application is started, the user uses the operation unit  23  to operate the control button  2063 , and selects a circular frame setting mode from a plurality of modes ( 1102 ). 
   In the circular frame setting mode, the user operates the operation unit  23 , and sets a center point of the circular frame for the taken image on the preview screen  201 . Subsequently, the user operates the operation unit  23  to set range points of the circular frame. Thereby, a circular area in which a straight line connecting the center point and range points forms a radius is determined as in the frame  208  of  FIG. 2  ( 1103 ). 
   After the circular frame is set by the application, the PC  20  prepares CTS command to set the circular frame ( 1104 ), and asynchronously transfers the CTS command to the camera sub-unit  11  ( 1105 ). In this case, the CTS command prepared in the PC  20  will be described with reference to  FIG. 13 . 
   In  FIG. 13 , the data similar to those in  FIG. 12  are set in a ctype field  1301 , Subunit_type field  1302 , Subunit ID field  1303 , opcode field  1304 , operand [ 0 ] field  1305 , and operand [ 1 ] field  1306 . 
   Moreover, in  FIG. 13 , data indicating a frame type “Frame Type” is set in an operand [ 2 ] field. In an operand [ 3 ] field a value of X coordinate of the center point of the circular frame “X position of center” is set, and in an operand [ 4 ] field a value of Y coordinate of the center point of the circular frame “Y position of center” is set. In an operand [ 5 ] field, a radius of the circular frame “radius” is set. 
   After receiving the above-described CTS command, the camera sub-unit  11  returns an acknowledgment to the PC  20  ( 1106 ). 
   Moreover, the camera sub-unit  11  executes a processing corresponding to the received CTS command ( 1107 ), and additionally prepares CTS response corresponding to the CTS command ( 1108 ). Additionally, for the CTS response, data are set in the same procedure as the CTS response of the rectangular frame. 
   After preparing the CTS response, the camera sub-unit  11  sets the CTS response in Asynchronous packet shown in  FIG. 26 , and transfers the packet to the PC  20  ( 1109 ). The PC  20  returns an acknowledgment of the CTS response to the camera sub-unit  11  ( 1110 ). 
   Subsequently, the PC  20  visually displays on the monitor  22  that the designated circular frame is set in the camera sub-unit  11  ( 1111 ). 
   By the above-described communication procedure, the application of the PC  20  can set a circular frame area for the taken image of the camera sub-unit  11 . 
   (2-3) Setting of Polygonal Frame 
   In the PC  20 , the user starts the application to display a screen on the monitor  22  as shown in  FIG. 2  ( 1101 ). 
   After the application is started, the user uses the operation unit  23  to operate the control button  2064 , and selects a polygonal frame setting mode from a plurality of modes ( 1102 ). 
   In the polygonal frame setting mode, the user operates the operation unit  23 , and sets a start point of the polygonal frame for the taken image on the preview screen  201 . Subsequently, the user operates the operation unit  23  to set a second point of the polygonal frame. Furthermore, the user operates the operation unit  23  to set third and subsequent points of the polygonal frame. Thereby, a polygonal area in which the start and second and subsequent points are sequentially connected by a straight line is determined as in the frame  209  of  FIG. 2  ( 1103 ). 
   After the polygonal frame is set by the application, the PC  20  prepares CTS command to set the polygonal frame ( 1104 ), and asynchronously transfers the CTS command to the camera sub-unit  11  ( 1105 ). In this case, the CTS command prepared in the PC  20  will be described with reference to  FIG. 14 . 
   In  FIG. 14 , the data similar to those in  FIG. 12  are set in a ctype field  1401 , Subunit_type field  1402 , Subunit ID field  1403 , opcode field  1404 , operand [ 0 ] field  1405 , and operand [ 1 ] field  1406 . 
   Moreover, in  FIG. 14 , data indicating a frame type “Frame Type” is set in an operand [ 2 ] field. In an operand [ 3 ] field the number of polygonal frame sides “Number of sides (n)” is set, and in operand [ 4 ] and subsequent fields a value of X coordinate of each apex “X position nth apex” and a value of Y coordinate “Y position nth apex” are set. 
   After receiving the above-described CTS command, the camera sub-unit  11  returns an acknowledgment to the PC  20  ( 1106 ). 
   Moreover, the camera sub-unit  11  executes a processing corresponding to the received CTS command ( 1107 ), and additionally prepares CTS response corresponding to the CTS command ( 1108 ). Additionally, in the CTS response, data are set in the same procedure as the CTS response of the rectangular frame. 
   After preparing the CTS response, the camera sub-unit  11  sets the CTS response in Asynchronous packet shown in  FIG. 26 , and transfers the packet to the PC  20  ( 1109 ). The PC  20  returns an acknowledgment of the CTS response to the camera sub-unit  11  ( 1110 ). 
   Subsequently, the PC  20  visually displays on the monitor  22  that the designated polygonal frame is set in the camera sub-unit  11  ( 1111 ). 
   By the above-described communication procedure, the application of the PC  20  can set a polygonal frame area for the taken image of the camera sub-unit  11 . 
   (2-4) Setting of Pixel Frame 
   In the PC  20 , the user starts the application to display a screen on the monitor  22  as shown in  FIG. 2  ( 1101 ). 
   After the application is started, the user uses the operation unit  23  to operate the control button  2065 , and selects a pixel frame setting mode from a plurality of modes ( 1102 ). 
   In the pixel frame setting mode, the user operates the operation unit  23 , and sets a pixel frame of one pixel for the taken image on the preview screen  201 . The pixel frame is set, for example, like the frame  210  of  FIG. 2  ( 1103 ). 
   After the pixel frame is set by the application, the PC  20  prepares CTS command to set the pixel frame ( 1104 ), and asynchronously transfers the CTS command to the camera sub-unit  11  ( 1105 ). In this case, the CTS command prepared in the PC  20  will be described with reference to  FIG. 15 . 
   In  FIG. 15 , the data similar to those in  FIG. 12  are set in a ctype field  1501 , Subunit_type field  1502 , Subunit ID field  1503 , opcode field  1504 , operand [ 0 ] field  1505 , and operand [ 1 ] field  1506 . 
   Moreover, in  FIG. 15 , data indicating a frame type “Frame Type” is set in an operand [ 2 ] field. In an operand [ 3 ] field a value of X coordinate of the pixel frame “X position” is set, and in an operand [ 4 ] field a value of Y coordinate of the pixel frame “Y position” is set. 
   After receiving the above-described CTS command, the camera sub-unit  11  returns an acknowledgment to the PC  20  ( 1106 ). 
   Moreover, the camera sub-unit  11  executes a processing corresponding to the received CTS command ( 1107 ), and additionally prepares CTS response corresponding to the CTS command ( 1108 ). Additionally, in the CTS response, data is set in the same procedure as the CTS response of the rectangular frame. 
   After preparing the CTS response, the camera sub-unit  11  uses the CTS response to prepare Asynchronous transfer packet shown in  FIG. 5 , and asynchronously transfers the packet to the PC  20  ( 1109 ). The PC  20  returns an acknowledgment of the CTS response to the camera sub-unit  11  ( 1110 ). 
   Subsequently, the PC  20  visually displays on the monitor  22  that the designated pixel frame is set in the camera sub-unit  11  ( 1111 ). 
   By the above-described communication procedure, the application of the PC  20  can set a pixel frame area for the taken image of the camera sub-unit  11 . 
   (3) Inquiry of Frame Area 
   In the embodiment, the application of the PC  20  can inquire of the camera sub-unit  11  about the frame area which is set in the taken image of the camera sub-unit  11 . A procedure for inquiring the frame area will be described hereinafter with reference to  FIG. 16 . 
   In the PC  20 , the user starts the application to display a screen on the monitor  22  as shown in  FIG. 2  ( 1601 ). 
   After the application is started, the user uses the operation unit  23  to select a desired frame from preset frames ( 1602 ). After the frame is selected, the user uses the operation unit  23  to instruct an inquiry of the frame area ( 1603 ). 
   After confirming the user&#39;s instruction input, the PC  20  prepares CTS command to inquire the frame area ( 1604 ), and asynchronously transfers the CTS command to the camera sub-unit  11  ( 1605 ). In this case, the CTS command prepared in the PC  20  will be described with reference to  FIG. 17 . 
   In  FIG. 17 , in a ctype field  1701  is set “Status” which indicates that the command is a status command to inquire a state of the camera sub-unit  11 . Data specifying the camera sub-unit  11  of DVCR  10  are stored in Subunit_type field  1702  and Subunit ID field  1703 . 
   Moreover, in  FIG. 17 , a code indicating a command “FRAME” concerning the frame control is set in an opcode field  1704 . A code indicating an area setting command “Area Set” is set in an operand [ 0 ] field  1705 . A frame number “Frame Number” of a frame whose area information is to be inquired is set in an operand [ 1 ] field  1706 . 
   After receiving the above-described CTS command, the camera sub-unit  11  returns an acknowledgment to the PC  20  ( 1606 ). 
   Moreover, the camera sub-unit  11  executes a processing corresponding to the received CTS command ( 1607 ), and additionally prepares CTS response corresponding to the CTS command ( 1608 ). 
   In this case, when the camera sub-unit  11  does not support “Frame Number” designated by the CTS command, the PC  20  prepares CTS response by setting “Rejected” to the response field. Furthermore, when the camera sub-unit  11  corresponds to “Frame Number” and “Frame Type” designated by the CTS command, the PC  20  prepares CTS response by setting “Stable” to the response field. 
   Moreover, the camera sub-unit  11  stores the data specifying the sub-unit provided in the target in the Subunit_type field and Subunit ID field of the CTS response. In the opcode field and the operand [ 0 ] and operand [ 1 ] fields, the same values as those set in the CTS command are set, respectively. 
   Furthermore, in operand [ 2 ] and subsequent fields of the CTS response, the area of the designated frame is set using data formats shown in  FIGS. 12 to 15 . When the area of the designated frame is not set, for example, dummy data like FF (hexadecimal) is set in the operand [ 2 ] field. 
   After preparing the CTS response, the camera sub-unit  11  sets the CTS response in Asynchronous packet shown in  FIG. 26 , and transfers the packet to the PC  20  ( 1609 ). 
   The PC  20  returns an acknowledgment of the CTS response to the camera sub-unit  11  ( 1610 ). Thereafter, the PC  20  uses parameter information included in the CTS response to visually display the area of the selected frame on the monitor  22  ( 1611 ). 
   By the above-described procedure, the PC  20  can confirm the frame area which is set in the taken image of the camera sub-unit  11 , and can additionally manage the frame area by the application of the PC  20 . 
   (4) Switching of Display/Not-Display of Object Frame 
   In the embodiment, the application of the PC  20  can select whether or not the frame set in the taken image of the camera sub-unit  11  is superimposed/displayed on the image. A procedure for switching displaying/not-displaying of the object frame will be described hereinafter with reference to  FIG. 18 . 
   In the PC  20 , the user starts the application to display a screen on the monitor  22  as shown in  FIG. 2  ( 1801 ). 
   After the application is started, the user uses the operation unit  23  to select an object or frame ( 1802 ). After the frame is selected, the user uses the operation unit  23  to instruct the displaying/not-displaying of the frame ( 1803 ). 
   After confirming the user&#39;s instruction input, the PC  20  prepares CTS command to switch the displaying/not-displaying ( 1804 ), and asynchronously transfers the CTS command to the camera sub-unit  11  ( 1805 ). In this case, the CTS command prepared in the PC  20  is shown in  FIG. 19 . 
   In  FIG. 19 , in a ctype field  1901  is set “Control” which indicates that the command is a control command to control the camera sub-unit  11 . Data specifying the camera sub-unit  11  of DVCR  10  are stored in Subunit_type field  1902  and Subunit ID field  1903 . 
   Moreover, in  FIG. 19 , a code indicating a command “FRAME” concerning the frame control is set in an opcode field  1904 . A code designating the displaying/not-displaying “Show/Hide” is set in an operand [ 0 ] field  1905 . An object or frame number “Frame Number” is set in an operand [ 1 ] field  1906 . 
   After receiving the above-described CTS command, the camera sub-unit  11  returns an acknowledgment to the PC  20  ( 1806 ). 
   Moreover, the camera sub-unit  11  executes a processing corresponding to the received CTS command ( 1807 ), and additionally prepares CTS response corresponding to the CTS command ( 1808 ). 
   In this case, when the camera sub-unit  11  supports “Frame Number” designated by the CTS command, but the area is not set in the object frame, the PC  20  prepares CTS response by setting “Rejected” to the response field. Furthermore, when the camera sub-unit  11  supports “Frame Number” designated by the CTS command, and the area is set in the object frame, the PC  20  prepares CTS response by setting “Accepted” to the response field. 
   Moreover, the camera sub-unit  11  stores the data specifying the sub-unit of the target in Subunit_type field and Subunit ID field of the CTS response. In the opcode field and the operand [ 0 ] and operand [ 1 ] fields, the same values as those set in the CTS command are set, respectively. 
   After preparing the CTS response, the camera sub-unit  11  sets the CTS response in Asynchronous packet shown in  FIG. 26 , and transfers the packet to the PC  20  ( 1809 ). 
   The PC  20  returns an acknowledgment of the CTS response to the camera sub-unit  11  ( 1810 ). Thereafter, the PC  20  visually displays on the monitor  22  a taken image to be isochronously transferred from the camera sub-unit and the object frame superimposed on the image ( 1811 ). 
   Here, when the CTS response with “Accepted” set therein is transferred, the camera sub-unit  11  switches the displaying/not-displaying of the object frame. 
   For example, when the object frame is a rectangular, circular, or polygonal frame, and a code “Show” instructing the display of the frame is set in the operand [ 0 ] field of the CTS command, the camera sub-unit  11  superimposes an outer rim of the object frame on the taken image, and isochronously transfers the taken image. Moreover, for the pixel frame, cross line display, circular rim display, rectangular rim display or another frame rim centering on the designated pixel is superimposed and displayed on the taken image. 
   Thereby, the camera sub-unit  11  can supply to the PC  20  the image in which the outer rim of the object frame is superimposed beforehand on the taken image. Moreover, when the DVCR  10  is equipped with a view finder, liquid crystal panel or another display unit, the image with the object frame superimposed on the taken image is also displayed on the display unit. 
   Additionally, when a code “Hide” instructing the not-displaying of the frame is set in the operand [ 0 ] field of the CTS command, the camera sub-unit  11  isochronously transfers the taken image to the PC  20  without overlapping the frame rim of the object frame onto the taken image. 
   By the above-described procedure, the PC  20  can instruct the displaying/not-displaying of the frame which is set in the taken image of the camera sub-unit  11 , and can additionally manage the displaying/not-displaying of the frame by the application of the PC  20 . 
   (5) Setting of Function of Object Frame 
   In the embodiment, for the camera sub-unit  11  the application of the PC  20  can set various functions of the frame set in the taken image of the camera sub-unit  11 . A procedure for setting the function of the object frame will be described hereinafter with reference to  FIG. 20 . 
   In the PC  20 , the user starts the application to display a screen on the monitor  22  as shown in  FIG. 2  ( 2001 ). 
   After the application is started, the user operates the control button  2061  by the operation unit  23  to select a desired frame ( 2002 ). For example, after the control button  2061  is clicked using a mouse, the frame  209  superimposed/displayed on the taken image on the preview screen  201  is double-clicked, so that the desired frame is selected. 
   After the frame is selected, the application of the PC  20  displays the menu window  211 , thereby allowing the user to select various functions to be set to the object frame ( 2003 ). Here, examples of the functions which can be selected from the menu window  211  include auto-focusing, automatic exposure, white balance, digital zoom and the like. 
   After confirming the user&#39;s instruction input, the PC  20  prepares CTS command to set a predetermined function to the object frame ( 2004 ), and asynchronously transfers the CTS command to the camera sub-unit  11  ( 2005 ). In this case, the CTS command prepared in the PC  20  is shown in  FIG. 21 . 
   In  FIG. 21 , a control command “Control” to control the camera sub-unit  11  is set in a ctype field  2101 . Data specifying the camera sub-unit  11  of DVCR  10  are stored in Subunit_type field  2102  and Subunit ID field  2103 . 
   Moreover, in  FIG. 21 , a code indicating a command “FRAME” concerning the frame control is set in an opcode field  2104 . A code indicating a function setting command “Function Set” is set in an operand [ 0 ] field  2105 . A code “Frame Number” indicating an object frame number and a code “Function Type” indicating a function to be set in the object frame are set in operand [ 1 ] and operand [ 2 ] fields  2106 . Here, examples of “Function Type” include functions shown in  FIG. 22 . 
   After receiving the above-described CTS command, the camera sub-unit  11  returns an acknowledgment to the PC  20  ( 2006 ). 
   Moreover, the camera sub-unit  11  executes a processing corresponding to the received CTS command ( 2007 ), and additionally prepares CTS response corresponding to the CTS command ( 2008 ). 
   In this case, when the camera sub-unit  11  does not support “Frame Number” and “Function Type” designated by the CTS command, the PC  20  prepares CTS response by setting “Rejected” to the response field. Furthermore, when the camera sub-unit  11  supports “Frame Number” and “Function type” designated by the CTS command, the PC  20  prepares CTS response by setting “Accepted” to the response field. 
   Moreover, the camera sub-unit  11  stores the data specifying the sub-unit of the target in Subunit_type field and Subunit ID field of the CTS response. In the opcode field and the operand [ 0 ] and operand [ 1 ] fields, the same values as those set in the CTS command are set, respectively. 
   After preparing the CTS response, the camera sub-unit  11  asynchronously transfers the CTS response to the PC  20  ( 2009 ). After receiving the CTS response, the PC  20  returns an acknowledgment of the CTS response to the camera sub-unit  11  ( 2010 ). 
   Here, the camera sub-unit  11  sets the function of the object frame in response to the received CTS command. For example, when “Function Type” included in the CTS command is auto-focusing “Auto Focus”, the camera sub-unit  11  auto-focuses the entire taken image based on the image of the object frame area, and isochronously transfers the result. Moreover, when “Function Type” included in the CTS command is digital zoom “Zoom”, the camera sub-unit  11  zooms up the entire taken image based on the image of the object frame area, and isochronously transfers the result. 
   After returning the acknowledgment to the camera sub-unit  11 , the PC  20  visually displays on the monitor  22  that the desired function is set in the object frame, and additionally displays the taken image prepared based on the function ( 2011 ). 
   For example, the application of the embodiment can change a color for displaying the outer rim of the object frame in accordance with the function selected/set by the user. In  FIG. 2 , when the function set in the frames  207  to  210  is the auto-focusing, the application displays the outer rim of the frame in red. When it is the white balance, the outer rim of the frame can be displayed in yellow. When such processing is performed on each frame, the function set in each frame can be visually displayed, and user interface can be enhanced further. 
   When the user is to select another frame and to set a desired function for the frame, by repeatedly performing the above-described procedure, various functions can be set for a plurality of frames. 
   By the above-described procedure, the PC  20  can set various functions for the frame which is set in the taken image of the camera sub-unit  11 , and can additionally manage the function of each frame by the application of the PC  20 . 
   Additionally, in the embodiment, the case where one function is set for the object frame has been described, but the present invention is not limited thereto. The embodiment may be constructed in such a manner that CTS command for setting the function is set a plurality of times, or a plurality of function types are set in one CTS command, such CTS command is transferred, and a plurality of functions are set for the object frame. 
   (6) Inquiry of Object Frame Function 
   In the embodiment, the application of the PC  20  can inquire of the camera sub-unit  11  about the function of the frame which is set in the taken image of the camera sub-unit  11 . A procedure for inquiring the function in the object frame will be described hereinafter with reference to  FIG. 23 . 
   In the PC  20 , the user starts the application to display a screen on the monitor  22  as shown in  FIG. 2  ( 2301 ). 
   After the application is started, the user operates the control button  2061  or the like of the operation unit  23  to select an object or frame ( 2302 ). For example, after the control button  2061  is clicked using a mouse, the frame  209  superimposed/displayed on the taken image on the preview screen  201  is double-clicked, so that the desired frame is selected. 
   After the object frame is selected, the user operates the operation unit  23  to instruct an inquiry of the frame function for the frame ( 2303 ). 
   After confirming the user&#39;s instruction input, the PC  20  prepares CTS command to inquire the object frame function ( 2304 ), and asynchronously transfers the CTS command to the camera sub-unit  11  ( 2305 ). In this case, the CTS command prepared in the PC  20  is shown in  FIG. 24 . 
   In  FIG. 24 , in a ctype field  2401 , a control command “Control” to control the camera sub-unit  11  is set. Data specifying the camera sub-unit  11  of DVCR  10  are stored in Subunit_type field  2402  and Subunit ID field  2403 . 
   Moreover, in  FIG. 24 , a code indicating a command “FRAME” concerning the frame control is set in an opcode field  2404 . A code indicating a function setting command “Function Set” is set in an operand [ 0 ] field  2405 . A code indicating an object frame number “Frame Number” and dummy data “FF (hexadecimal)” are set in operand [ 1 ] and operand [ 2 ] fields  2406 . 
   After receiving the above-described CTS command, the camera sub-unit  11  returns an acknowledgment to the PC  20  ( 2306 ). 
   Moreover, the camera sub-unit  11  executes a processing corresponding to the received CTS command ( 2307 ), and additionally prepares CTS response corresponding to the CTS command ( 2308 ). 
   In this case, when the camera sub-unit  11  does not support “Frame Number” designated by the CTS command, the PC  20  prepares CTS response by setting “Rejected” to the response field. Furthermore, when the camera sub-unit  11  supports “Frame Number” designated by the CTS command, the PC  20  prepares CTS response by setting “Stable” to the response field. 
   Moreover, the DVCR  10  stores the data specifying the sub-unit provided in the target in Subunit_type field and Subunit ID field of the CTS response. In the opcode field and the operand [ 0 ] and operand [ 1 ] fields, the same values as those set in the CTS command are set, respectively. 
   Furthermore, the DVCR  10  sets a code indicating the function set in the object frame into an operand [ 2 ] field of the CTS response. Examples of the code include data shown in  FIG. 22 . When the function is not set in the object frame, dummy data FF (hexadecimal) is set. 
   After preparing the CTS response, the camera sub-unit  11  uses the CTS response to prepare Asynchronous transfer packet shown in  FIG. 5 , and asynchronously transfers the packet to the PC  20  ( 2309 ). 
   The PC  20  returns an acknowledgment of the CTS response to the camera sub-unit  11  ( 2310 ). Thereafter, the PC  20  visually displays the function of the object frame on the monitor  22  based on the CTS response ( 2311 ). 
   By the above-described procedure, the PC  20  can confirm the frame function set in the taken image of the camera sub-unit  11 , and can additionally manage the function which can be set in each frame by the application of the PC  20 . 
   Additionally, in the first embodiment, the present invention can variously be embodied without departing from spirits, or main characteristics thereof. 
   For example, in the embodiment, the storage medium  24  has been described as the hard disc, but is not limited thereto. The storage medium may be a floppy disc, optical disc, optical magnetic disc, CD-ROM, CD-R, magnetic tape, non-volatile memory card, ROM or the like as long as it can supply the program code for realizing the embodiment to the control unit  21 . 
   Moreover, the program code stored in the storage medium  24  of the embodiment may be recorded beforehand, or supplied from the outside via the digital interface  40  before recorded in the storage medium  24 . 
   Therefore, the above-described embodiment is only an illustration in all respects, and should not be restrictedly construed. 
   Also, though the embodiment is explained according to an example, that is data communication system based upon the IEEE 1394 standard, the present invention can be applied to other data communication system. That is, it is possible to apply to data communication systems which can utilize a data communication method assuring real-time data transfer of the moving image data etc. as Isochronous transfer system and a data communication method transferring necessary information to a designated device without preventing the real-time data communication as Asynchronous transfer system. 
   As described above, according to the first embodiment, the setting and inquiring of the frame of the taken image of the target, and the setting and inquiring of various functions of the frame can be remote-operated from the controller. 
   Particularly, by the remote operation, the controller can confirm the maximum number of frames which can be set in the taken image of the target. 
   Moreover, by the remote operation, the controller can set a plurality of frames having different areas, or shapes for the taken image of the target. 
   Furthermore, by the remote operation, the controller can confirm the frame area which is preset in the taken image of the target. 
   Additionally, by the remote operation, the controller can instruct the displaying/not-displaying of the frame set in the taken image of the target. 
   Moreover, by the remote operation, the controller can set various functions for the frame set in the taken image of the target. 
   Furthermore, by the remote operation, the controller can confirm the function of the frame set in the taken image of the target. 
   Second Embodiment 
   In a second embodiment, an operation environment will be described in which IEEE 1394 serial bus or another network is connected to a target having a display unit and a controller for remote-operating the display unit, and the controller is used to control a displayed image of the display unit. 
   Moreover, in the second embodiment, an operation environment will be described in which IEEE 1394 serial bus or another network is connected to a target having a camera unit and a controller for remote-operating the camera unit, and the controller is used to control a taken image of the camera unit. 
   Furthermore, in the second embodiment, an operation environment will be described in which IEEE 1394 serial bus or another network is connected to a first target having a display unit, a second target having a camera unit and a controller for remote-operating the display unit and the camera unit, and a displayed image of the display unit and a taken image of the camera unit are controlled. 
   In  FIGS. 25A and 25B , numeral  2510  denotes a computer,  2512  denotes an operation processing unit (MPU),  2514  denotes a first 1394 interface,  2516  denotes a first operation unit comprising a keyboard, mouse and the like,  2518  denotes a first decode,  2520  denotes CRT display or another display unit,  2522  denotes a hard disc,  2524  denotes a first memory,  2526  denotes PCI bus or another computer internal bus, and  2528  denotes a first 1394 interface terminal. 
   Numeral  2530  denotes a digital television (hereinafter referred to as DTV),  2532  denotes a second 1394 interface,  2534  denotes a first data selector,  2536  denotes a second operation unit,  2538  denotes a TV controller,  2540  denotes a second decode,  2542  denotes a second memory,  2544  denotes an image processing circuit,  2546  denotes a third memory, and  2548  denotes a display unit including a cathode ray tube (hereinafter referred to as CRT) and the like. 
   Numeral  2550  denotes a second 1394 interface terminal,  2552  denotes a third 1394 interface terminal,  2554  denotes an image input terminal,  2556  denotes a camera incorporating type digital video recorder (hereinafter referred to as DVCR),  2558  denotes an image pickup unit including an image pickup optical system,  2560  denotes an A/D converter,  2562  denotes a video processing unit,  2564  denotes a compression/expansion circuit,  2566  denotes a fourth memory,  2568  denotes a fifth memory,  2570  denotes a second data selector, and  2572  denotes a third 1394 interface. 
   Numeral  2574  denotes a memory control circuit,  2576  denotes a system controller,  2578  denotes a third operation unit,  2580  denotes an electronic view finder,  2582  denotes a D/A converter,  2584  denotes a recorder or another recording section (hereinafter referred to as the recorder),  2586  denotes a fourth 1394 interface terminal, and  2588  denotes EEPROM or another writable read only memory (hereinafter referred to as EEPROM). 
   The computer  2510 , DTV  2530 , and DVCR  2556  are nodes, and the nodes are interconnected via the first to third 1394 interfaces  2514 ,  2532 ,  2572 . The nodes can transmit/receive data, or can mutually perform remote operation or the like by a command described later. 
   In the embodiment, for example, the computer  2510  operates as a controller for controlling a flow of image signals on the 1394 serial bus, or as a controller for remote-operating the DTV  2530  and DVCR  2556 . 
   An internal constitution of the computer  2510  will next be described. The PCI bus or another computer internal bus  2526  is interconnected to the control unit (including MPU)  2512 , 1394 interface  2514 , first operation unit  2516 , decoder  2518 , display unit (including CRT display)  2520 , hard disc  2522 , internal memory  2524  and another device. 
   The control unit  2512  executes software recorded in the hard disc  2522 , and additionally moves various data to the internal memory  2524 . Moreover, the control unit  2512  also performs adjusting operation of the devices interconnected via the PCI bus  2526 . 
   The 1394 interface  2514  receives an image signal transferred on the 1394 serial bus, and additionally transmits an image signal recorded in the hard disc  2522  and an image signal stored in the internal memory  2524  via the 1394 interface terminal  2528 . The image signals are transmitted using Isochronous communication. Moreover, the 1394 interface  2514  asynchronously transfers CTS command for another apparatus connected on the 1394 serial bus via the first 1394 interface terminal  2528 . 
   Moreover, the 1394 interface  2514  transfers a signal transferred onto the 1394 serial bus to another 1394 node via the 1394 interface terminal  2528 . 
   An operator allows the MPU  2512  to execute the software recorded in the hard disc  2522  through the operation unit  2516  comprising the keyboard, mouse and the like. The software and another information are presented to the operator by the display unit  2520  including the CRT display and the like. 
   The decoder  2518  decodes the image signal received from the 1394 serial bus through the software. The decoded image signal is also presented to the operator by the display unit  2520 . 
   The inner constitution of the DTV  2530  will next be described. 
   In the embodiment, the DTV  2530  operates as an image output device. The second 1394 interface  2532  receives the image signal transferred onto the 1394 serial bus and command data for controlling the DTV  2530  via the 1394 serial bus, 1394 interface terminal  2550 , and 1394 interface terminal  2552 . 
   The image signal is received, for example, using Isochronous transfer. Moreover, the 1394 interface  2532  asynchronously transfers the CTS response to the CTS command. Furthermore, the 1394 interface  2532  transfers to another node the signal transferred onto the 1394 serial bus. 
   The received image data is transmitted to the decoder  2540  through the data selector  2534 . The decoder  2540  temporarily stores the image data in the memory  2542  to decode the data, and transmits an output to the image processing circuit  2544 . The image processing circuit  2544  applies various processings to the decoded image data, then transmits an output to the display unit (including CRT)  2548  for display. Additionally, means constituting the display unit  2548  is not limited to the CRT, and needless to say, a liquid crystal display device, plasma device, or another display device can be used. 
   On the other hand, the received CTS command is transmitted to the TV controller  2538  through the data selector  2534 . In response to the CTS command, the TV controller  2538  allows the data selector  2570  to switch input signals, allows the image processing circuit  2544  to control image qualities of output images, and performs other controls about various images. Moreover, the TV controller  2538  stores image quality control information of the output images in the memory  2546 . 
   Moreover, for example, digital and analog image signals are transmitted from an image input apparatus (not shown) via the image input terminal  2554 . The inputted digital signal is transmitted to the decoder  2540  through the data selector  2534 . 
   The decoder  2540  temporarily stores the image data in the memory  2542  to decode the data, and transmits an output to the image processing circuit  2544 . The image processing circuit  2544  applies various processings to the decoded image data, then transmits an output to the display unit  2548  for display. 
   Switching of image input to any one of the 1394 interfaces  2550 ,  2552  and the image input terminal  2554  is performed by the data selector  2534 . When the input terminal is set by the operation unit  2536 , or the received CTS command, the TV controller  2538  instructs the data selector  2534  to set inputs. Following the instruction of the input setting, the data selector  2534  outputs an appropriate input signal. 
   An internal constitution of the DVCR  2556  will next be described. 
   In the embodiment, the DVCR  2556  operates as an input device of image signals. A luminance signal (Y) and color-difference signal (C) of the image transmitted from the image pickup unit  2558  are converted to digital data by the A/D converter  2560 . The digital data is multiplexed by the video processing unit  2562 . Subsequently, the data amount of the image information is compressed by the compression/expansion circuit  2564 . 
   Generally, YC is independently provided with the compression processing circuit, but here for the simplicity of the description, an example of a compression processing in YC time division is described. Subsequently, a shuffling processing is applied for the purpose of strengthening the image data against a transmission line error. An object of the processing is to convert a continuous code error or burst error to a random error as a discrete error which can easily be corrected or interpolated. 
   In addition, to make much of an object of uniforming a deviation of generation of information amount by coarseness in the image screen, when the processing is performed before the compression processing, run length or another variable length code is conveniently used. In response to this, data identification (ID) information for restoring the data shuffling is added. 
   The ID added by the ID adding operation, together with simultaneously recorded mode information and the like of the above-described system, is used as auxiliary information for a reverse compression processing (information amount expansion processing) during reproduction. In order to reduce an error during the reproduction of the data, error correction (ECC) information is added. The processing till the addition of such redundancy signal is applied for each independent record area corresponding to each image, voice or another information. 
   As described above, the image signal with ID and ECC information added thereto is recorded in a magnetic tape or another recording medium by the recorder  2584 , and additionally stored temporarily in the fourth memory  2566  described later. 
   On the other hand, the image data multiplexed by the video processing unit  2562  is digital-analog converted by the D/A converter  2582 , and observed with the electronic view finder  2580  by the operator. Moreover, the operator transmits various operation information to the system controller  2576  via the operation unit  2578 . The system controller  2576  controls the entire DVCR  2556  by the operation information. 
   Moreover, the image data multiplexed by the video processing unit  2562  is transmitted to the memory  2568 , and temporarily stored. Operations of the memories  2566  and  2568  are controlled by the system controller  2576  via the memory control circuit  2574 . 
   The data selector  2570  selects the data from the memories  2566  and  2568  to transfer the data to the 1394 interface  2572 , or selects the data from the 1394 interface  2532  to transfer the data to the memory  2566  or the memory  2568 . By the above-described operation, from the 1394 interface  2572  in the DVCR  2556 , the compressed image data and non-compressed image data can be selected by the operator for Isochronous transfer. 
   The 1394 interface  2572  receives CTS command for controlling the DVCR  2556  via the 1394 serial bus and the 1394 interface terminal  2586 . The received CTS command is transmitted to the system controller  2576  through the data selector  2570 . 
   The system controller  2576  prepares CTS response for the CTS command, and transmits the CTS response to the 1394 serial bus through the data selector  2534  and the third 1394 interface  2572 . 
   Moreover, in response to the command data, the system controller  2576  also performs a control on the recorder  2584  and the video processing unit  2562 . The video processing unit  2562  adjusts the image quality of the video signal to be recorded by the control from the system controller  2576 . 
   The image quality adjustment information is written in the EEPROM  2588 , and can be stored even if main power of the DVCR  2556  is cut off. The writing of the image quality adjustment information into the EEPROM  2588  is performed, for example, when 1394 connector of an arbitrary apparatus in the bus is pulled off, or when a bus reset accompanied by the power cutting-off of the arbitrary apparatus in the bus is detected. 
     FIGS. 27A and 27B  show frame structures of CTS command and CTS response for use in the second embodiment. 
     FIG. 27A  shows the command frame structure, and  FIG. 27B  shows the response frame structure. 
   In  FIG. 27A , numeral  2750  denotes a command type (hereinafter referred to as ctype) field,  2752  denotes a sub-unit type (hereinafter referred to as subunit_type) field,  2754  denotes a sub-unit ID (hereinafter referred to as subunit_ID) field, and  2756  denotes an operation code (hereinafter referred to as opcode). 
   In  FIG. 27A , after the opcode  2756 , till the nth byte, each byte of operand [ 0 ], operand [ 1 ], . . . , and operand [n] continues. 
   The ctype  2750  (4 bits) shows the command type. One example of a relationship of the value of the ctype  2750  and the command type is shown in the following Table 1. 
   
     
       
             
             
             
           
         
             
                 
               TABLE 1 
             
             
                 
                 
             
             
                 
               code 
                 
             
             
                 
               (binary) 
             
             
                 
               MSB LSB 
               Command Type 
             
             
                 
                 
             
           
           
             
                 
               0000 
               CONTROL 
             
             
                 
               0001 
               STATUS 
             
             
                 
               0010 
               SPECIFIC INQUIRY 
             
             
                 
               0011 
               NOTIFY 
             
             
                 
               0100 
               GENERAL INQUIRY 
             
             
                 
               0101 
               (reserved) 
             
             
                 
               0110 
               (reserved) 
             
             
                 
               0111 
               (reserved) 
             
             
                 
                 
             
           
        
       
     
   
   In Table 1, when the value of the ctype  2750  is CONTROL, the controller controls the target. The control content is designated by the operand and opcode described later. Moreover, when the value of the ctype  2750  is STATUS, the controller inquires the current state of the target. The state is designated by the operand and opcode described later. 
   Moreover, when the value of the ctype  2750  is NOTIFY, the controller notifies by the target that the state of the target is changed. The state is designated by the operand and opcode described later in the same manner as STATUS command. 
   Furthermore, when the value of the ctype  2750  is SPECIFIC INQUIRY, or GENERAL INQUIRY, it is confirmed whether or not the CONTROL command having the same opcode is mounted on the target. 
   In the SPECIFIC INQUIRY command, the opcode and all operands have to be designated, but in the GENERAL INQUIRY command, only the opcode is designated. This respect is a difference between the two INQUIRY commands. 
   With the subunit_type  2752  (5 bits) and the subunit_ID  2754  (3 bits), the sub-unit to which the CTS command is to be sent is identified. 
   The subunit is a virtual entry which is identified as only one in one node (hereinafter referred to as the unit) and which provides a consistent function set. 
   One unit can have a plurality of subunits. Therefore, the subunit_type  2752  and the subunit_ID  2754  indicate an address for identifying a certain subunit which is present in one unit. 
   The following Table 2 shows one example of a relationship of a value of subunit_type  2752  and a subunit type. The subunit_type  2752  and subunit_ID  2754  are generically referred to as a subunit address. 
   Additionally, when the value of the subunit_type  2752  is “1F 16 ” and the value of the subunit_ID  2754  is “3 16 ”, the subunit address indicates the unit. 
   When the CTS command is transmitted to the display unit  2548  of the DTV  2530  in the embodiment, for example, a value “0000 2 ” is designated in the subunit_type  2752 , and a value “000 2 ” is designated in the subunit_ID  2754 . Moreover, when the command is transmitted to the camera unit  2558  of the DVCR  2556  in the embodiment, for example, a value “00111 2 ” is designated in the subunit_type  2752 , and a value “000 2 ” is designated in the subunit_ID  2754 . Furthermore, when the command is transmitted to a VCR subunit of the DVCR  2556  in the embodiment, a value “00100 2 ” is designated in the subunit_type  2752 , and a value “ 000   2 ” is designated in the subunit_ID  2754 . 
   The opcode  2756  defines a control content to be performed, and a state returned by the CTS response described later. The number and meaning of subsequent operands differ in accordance with the contents of the ctype, subunit_type and opcode. 
   
     
       
             
             
             
           
         
             
                 
               TABLE 2 
             
             
                 
                 
             
             
                 
               Code 
                 
             
             
                 
               (binary) 
             
             
                 
               MSB LSB 
               Subunit Type 
             
             
                 
                 
             
           
           
             
                 
               00000 
               Video Monitor 
             
             
                 
               00001 
               (reserved) 
             
             
                 
               00010 
               (reserved) 
             
             
                 
               00011 
               disc recorder/player 
             
             
                 
               00100 
               Video Cassette Recorder (VCR) 
             
             
                 
               00101 
               Tuner 
             
             
                 
               00110 
               (reserved) 
             
             
                 
               00111 
               Video Camera 
             
             
                 
               01000 
               (reserved) 
             
             
                 
               . 
             
             
                 
               . 
             
             
                 
               . 
             
             
                 
               11011 
             
             
                 
               11100 
               Vendor unique 
             
             
                 
               11101 
               (reserved) 
             
             
                 
               11110 
               Extended subunit_type 
             
             
                 
               11111 
               Unit 
             
             
                 
                 
             
           
        
       
     
   
   In  FIG. 27B , the same reference numerals as those in  FIG. 27A  denote fields indicating the same functions. Moreover, in  FIG. 27B , numeral  2758  denotes a response field (hereinafter referred to as response). The response  2758  indicates a CTS response type. Table 3 shows one example of a relationship of a value of response  2758  and the response type. 
   
     
       
             
             
             
           
         
             
                 
               TABLE 3 
             
             
                 
                 
             
             
                 
               code 
                 
             
             
                 
               (binary) 
             
             
                 
               MSB LSB 
               Response 
             
             
                 
                 
             
           
           
             
                 
               1000 
               NOT IMPLEMENTED 
             
             
                 
               1001 
               ACCEPTED 
             
             
                 
               1010 
               REJECTED 
             
             
                 
               1011 
               IN TRANSITION 
             
             
                 
               1100 
               IMPLEMENTED/STABLE 
             
             
                 
               1101 
               CHANGED 
             
             
                 
               1110 
               (reserved) 
             
             
                 
               1111 
               INTERIM 
             
             
                 
                 
             
           
        
       
     
   
   The target prepares the corresponding CTS response by the ctype  2750 , subunit address  2752 ,  2754 , opcode  2756 , and operand of the CTS command transmitted from the controller, and returns it to the controller. 
   The CTS command for remote-operating the DTV  2530  of the embodiment will next be described. In the embodiment, for example, CTS commands shown in Table 4 are defined. These are commands for controlling an image displayed by the display unit  2548  of the DTV  2530 . 
   The commands shown in Table 4 are transferred to the target or DTV  2530  from the controller or computer  2510  by a procedure shown in  FIG. 30 . The procedure for remote-operating a display screen of DTV  2530  will be described hereinafter with reference to  FIG. 30 . 
   The controller  2512  of the computer  2510  reads a program stored in HD  2522 , and starts an application for remote-operating the display unit of DTV  2530  ( 3001 ). 
   After the application is started, the user operates the operation unit  2516  to select a function to be controlled. The user can select six types of functions: APERTURE; BRIGHTNESS; CHROMA; CONTRAST; PHASE; and INPUT SIGNAL MODE. The CTS commands shown in Table 4 correspond to these functions, and each command is prepared in accordance with a user&#39;s request for operation ( 3002 ). 
   CTS command types shown in Table 4 and functions corresponding to the commands will be described hereinafter. 
   
     
       
             
             
             
           
         
             
                 
               TABLE 4 
             
             
                 
                 
             
             
                 
               Name 
               opcode value 
             
             
                 
                 
             
           
           
             
                 
               APERTURE 
               40 16   
             
             
                 
               BRIGHTNESS 
               41 16   
             
             
                 
               CHROMA 
               42 16   
             
             
                 
               CONTRAST 
               43 16   
             
             
                 
               PHASE 
               44 16   
             
             
                 
               INPUT SIGNAL MODE 
               79 16   
             
             
                 
                 
             
           
        
       
     
   
   In Table 4, APERTURE is a command by which a contour compensating function on the display screen of the DTV  2530  is controlled and the current state is inquired. When the control is performed on the contour compensating function, CONTROL is set in the ctype  2750  of the CTS command. Moreover, when the current state is inquired for the contour compensating function, STATUS is set in the ctype  2750  of the CTS command. 
   With the APERTURE command with CONTROL being set therein, for example, one operand is designated. The controller or computer  2510  transmits the CTS command with a value of eight bits being set in the operand as APERTURE CONTROL command ( 3003 ). 
   Upon receiving the APERTURE CONTROL command, the DTV  2530  sets the contour compensation in accordance with the operand ( 3004 ). Additionally, the opcode value of the APERTURE command is not limited to “40 16 ”, and another value may be defined. Moreover, the number of operands to be designated is not limited to one, and needless to say, one or more operands may be designated. 
   In Table 4, BRIGHTNESS is a command by which the brightness on the display screen of the DTV  2530  is controlled and the current state is inquired. When the brightness on the display screen is controlled, CONTROL is set in the ctype  2750 . Moreover, when the current state is inquired for the brightness on the display screen, STATUS is set in the ctype  2750 . 
   With the BRIGHTNESS command with CONTROL being set therein, for example, one operand is designated. The controller or computer  2510  transmits the CTS command with a value of eight bits being set in the operand as BRIGHTNESS CONTROL command ( 3003 ). 
   Upon receiving the BRIGHTNESS CONTROL command, the DTV  2530  adjusts the brightness on the display screen in accordance with the operand ( 3004 ). For example, when the operand has a large value, the display screen is set bright. When the operand has a small value, the display screen is set dark. Additionally, the opcode value of the BRIGHTNESS command is not limited to “41 16 ”, and another value may be defined. Moreover, the number of operands to be designated is not limited to one, and needless to say, one or more operands may be designated. 
   In Table 4, CHROMA is a command by which color density on the display screen of the DTV  2530  is controlled and the current state is inquired. When the color density is controlled, CONTROL is set in the ctype  2750 . Moreover, when the current state is inquired for the color density, STATUS is set in the ctype  2750 . 
   With the CHROMA command with CONTROL set therein, for example, one operand is designated. The controller or computer  2510  transmits the CTS command with a value of eight bits set in the operand as CHROMA CONTROL command ( 3003 ). 
   Upon receiving the CHROMA CONTROL command, the DTV  2530  adjusts the color density on the display screen in accordance with the operand ( 3004 ). For example, when the operand has a large value, deep color is displayed. When the operand has a small value, light color is displayed. Additionally, the opcode value of the CHROMA command is not limited to “42 16 ”, and another value may be defined. Moreover, the number of operands to be designated is not limited to one, and one or more operands may be designated. 
   In Table 4, PHASE is a command by which tint on the display screen of the DTV  2530  is controlled and the current state is inquired. When the tint is controlled, CONTROL is set in the ctype  2750 . Moreover, when the current state is inquired for the tint, STATUS is set in the ctype  2750 . 
   With the PHASE command with CONTROL being set therein, for example, one operand is designated. The controller or computer  2510  transmits the CTS command with a value of eight bits being set in the operand as PHASE CONTROL command ( 3003 ). 
   Upon receiving the PHASE CONTROL command, the DTV  2530  adjusts the tint on the display screen in accordance with the operand ( 3004 ). For example, when the operand has a large value, green is displayed strong. When the operand has a small value, purple is set to be displayed strong. Additionally, the opcode value of the PHASE command is not limited to “44 16 ”, and another value may be defined. Moreover, the number of operands to be designated is not limited to one, and one or more operands may be designated. 
   In the above-described constitution, the image quality adjustment of the image displayed by the DTV  2530  on the 1394 serial bus can easily be remote-operated by the computer  2510  or another control device. 
   In Table 4, INPUT SIGNAL MODE is a command by which a type of an image signal to be transmitted to the DTV  2530  is designated, or a type of an image signal being transmitted to the DTV  2530  is inquired. 
     FIG. 28  is a view showing a data format of the INPUT SIGNAL MODE command on and after the opcode. In  FIG. 28 , signal_mode to be set in the operand [ 0 ] indicates the type of the input image signal. Table 5 shows codes to be set in the signal_mode and an example of each content. 
   
     
       
             
             
             
           
         
             
                 
               TABLE 5 
             
             
                 
                 
             
             
                 
               Value 
               Signal mode 
             
             
                 
                 
             
           
           
             
                 
               00 16   
               SD 525-60 
             
             
                 
               04 16   
               SDL 525-60 
             
             
                 
               08 16   
               HD 1125-60 
             
             
                 
               80 16   
               SD 625-50 
             
             
                 
               84 16   
               SDL 625-50 
             
             
                 
               88 16   
               HD 1250-50 
             
             
                 
               10 16   
               MPEG 25 Mbps-60 
             
             
                 
               14 16   
               MPEG 12.5 Mbps-60 
             
             
                 
               18 16   
               MPEG 6.25 Mbps-60 
             
             
                 
               90 16   
               MPEG 25 Mbps-50 
             
             
                 
               94 16   
               MPEG 12.5 Mbps-50 
             
             
                 
               98 16   
               MPEG 6.25 Mbps-50 
             
             
                 
               01 16   
               D-VHS Digital 
             
             
                 
               05 16   
               Analog VHS NTSC 525/60 
             
             
                 
               25 16   
               Analog VHS M-PAL 525/60 
             
             
                 
               A5 16   
               Analog VHS PAL 625/50 
             
             
                 
               B5 16   
               Analog VHS N-PAL 625/50 
             
             
                 
               C5 16   
               Analog VHS SECAM 625/50 
             
             
                 
               D5 16   
               Analog VHS ME-SECAM 625/50 
             
             
                 
               0D 16   
               Analog S-VHS 525/60 
             
             
                 
               ED 16   
               Analog S-VHS 625/50 
             
             
                 
               30 16   
               Baseband 525-60/422 Component Digital 
             
             
                 
               32 16   
               Baseband 525-60 Composite Digital 
             
             
                 
               34 16   
               Baseband 525-60/411 Digital 
             
             
                 
               B0 16   
               Baseband 625-50/422 Component Digital 
             
             
                 
               B2 16   
               Baseband 625-50 Composite Digital 
             
             
                 
               B4 16   
               Baseband 625-50/420 Digital 
             
             
                 
                 
             
           
        
       
     
   
   In the above-described constitution, the DTV  2530  of the embodiment can be adapted to various types of image signals, can know beforehand the type of the image signal to be inputted, and can notify another apparatus of the type of the image signal being inputted. 
   After the processing corresponding to each CTS command is executed, the controller  2538  of the DTV  2530  prepares the CTS response corresponding to the CTS command ( 3005 ). Subsequently, the 1394 interface  2532  of the DTV  2530  packetizes the CTS response into Asynchronous packet shown in  FIG. 26 , and write transaction of the packet into a response register of the computer  2510  is performed ( 3006 ). The controller  2512  of the computer  2510  distinguishes the content of the CTS response, and displays a result of the CTS command on the display  2520  ( 3007 ). 
   By the above-described procedure, the computer  2510  can remote-operate the image displayed by the display unit  2548  of the DTV  2530 , and can additionally manage the displayed image of the display unit  2548  by the application of the computer  2510 . 
   A command for remote-operating the DVCR  2556  of the embodiment will next be described. In the embodiment, for example, commands shown in Table 6 are defined. These are commands for controlling an image taken by the image pickup unit  2558  of the DVCR  2556 . 
   Each command shown in Table 6 is transferred to the target or DVCR  2556  from the controller or computer  2510  by a procedure shown in  FIG. 31 . A procedure for remote-operating a display screen of the DVCR  2556  will be described hereinafter with reference to  FIG. 31 . 
   The controller  2512  of the computer  2510  reads a program stored in the HD  2522 , and starts an application for remote-operating the image pickup unit of the DVCR  2556  ( 3101 ). 
   After the application is started, the user operates the operation unit  2516  to select a function to be controlled. The user can select eight types of functions: AE MODE; AE LOCK; APERTURE CORRECTION; GAIN; GAMMA; KNEE; WHITE BALANCE; and OUTPUT SIGNAL MODE. CTS commands shown in Table 6 correspond to these functions, and each command is prepared in response to the user&#39;s request for operation ( 3102 ). 
   Types of the CTS commands shown in Table 6 and the functions corresponding to the commands will be described hereinafter. 
   
     
       
             
             
             
           
         
             
                 
               TABLE 6 
             
             
                 
                 
             
             
                 
               Name 
               opcode value 
             
             
                 
                 
             
           
           
             
                 
               AE MODE 
               40 16   
             
             
                 
               AE LOCK 
               41 16   
             
             
                 
               APERTURE CORRECTION 
               50 16   
             
             
                 
               GAIN 
               51 16   
             
             
                 
               GAMMA 
               52 16   
             
             
                 
               KNEE 
               53 16   
             
             
                 
               WHITE BALANCE 
               5D 16   
             
             
                 
               OUTPUT SIGNAL MODE 
               78 16   
             
             
                 
                 
             
           
        
       
     
   
   In Table 6, AE MODE CONTROL command is used to control an automatic exposure system. Moreover, AE MODE STATUS command is used to inquire the automatic exposure system. 
   Furthermore, AE LOCK CONTROL command is used to fix exposure to a constant value, i.e., to control so-called AE LOCK. Additionally, AE LOCK STATUS command is used to inquire the current AE LOCK state. 
   The APERTURE CORRECTION CONTROL command is used to control the contour compensating function of the camera. Moreover, APERTURE CORRECTION STATUS command is used to inquire the current contour compensating function state of the camera. 
   The GAIN CONTROL command is used to control a gain of a signal processing system in the DVCR  2556 . A value of the gain can be controlled for luminance, color difference, or RGB or another signal type. Moreover, GAIN STATUS command is used to inquire the current gain value. In the same manner as the GAIN CONTROL command, GAIN STATUS command can inquire the gain value for the luminance, color difference, or RGB or another signal type. 
   The GAMMA CONTROL command is used to control a gamma value. The gamma value can be controlled for the luminance, color difference, or RGB or another signal type. Moreover, GAMMA STATUS command is used to inquire the current gamma value. In the same manner as the GAMMA CONTROL command, GAMMA STATUS command can inquire the gamma value for the luminance, color difference, or RGB or another signal type. 
   The KNEE CONTROL command is used to set a knee slope and knee point. 
   The KNEE STATUS command is used to inquire the current knee slope and knee point. 
   The WHITE BALANCE CONTROL command is used to set a white balance of the camera. In the setting of the white balance, parameters of both the color temperature conversion information and the setting in the current light source can be set. The WHITE BALANCE STATUS command is used to inquire the current camera white balance. 
   The OUTPUT SIGNAL MODE CONTROL command designates a type of a signal outputted by the camera sub-unit in the DVCR  2556 . The OUTPUT SIGNAL MODE STATUS command is used to inquire the type of the signal outputted by the camera sub-unit in the DVCR  2556 . 
   The OUTPUT SIGNAL MODE has one operand, and designates a type of a signal outputted by the operand. For a code value of the operand, the same value as the code value of the signal_mode field in the INPUT SIGNAL MODE command of the DTV  2530  is used. 
   After the processing corresponding to each CTS command is executed, the controller  2576  of the DVCR  2556  prepares CTS response corresponding to the CTS command ( 3105 ). Subsequently, the 1394 interface  2572  of the DVCR  2556  packetizes the CTS response into Asynchronous packet shown in  FIG. 26 , and write transaction of the packet into a response register of the computer  2510  is performed ( 3106 ). The controller  2512  of the computer  2510  distinguishes the content of the CTS response, and displays a result of the CTS command on the display  2520  ( 3107 ). 
   By the above-described procedure, the computer  2510  can remote-operate the image taken by the image pickup unit  2558  of the DVCR  2556 , and can additionally manage the taken image of the image pickup unit  2558  by the application of the computer  2510 . 
     FIG. 29  shows one example of a graphical user interface (hereinafter referred to as GUI) of an image quality setting application operated on the computer  2510 . The application performs an image quality adjustment of the DTV  2530  using the above-described CTS command. 
   In  FIG. 29 , numeral  2970  denotes a monitor screen,  2972  denotes an image preview screen,  2974  denotes a brightness adjustment sliding bar for adjusting brightness,  2976  denotes a contrast adjustment sliding bar for adjusting contrast,  2978  denotes a color adjustment sliding bar for adjusting tint,  2980  denotes a color density adjustment sliding bar for adjusting color density, and  2982  denotes a resolution adjustment sliding bar for adjusting resolution. 
   When the brightness adjustment sliding bar  2974  is moved to the right, for example, the brightness of the display surface of the DTV  2530  is set to become bright. The application generates an operand of the BRIGHTNESS CONTROL command in accordance with a position of the brightness adjustment sliding bar  2974 , and transmits the operand to the DTV  2530 . 
   When the contrast adjustment sliding bar  2976  is moved to the right, for example, the contrast of the display surface of the DTV  2530  is set to become large. The application generates an operand of the CONTRAST CONTROL command in accordance with a position of the contrast adjustment sliding bar  2976 , and transmits the operand to the DTV  2530 . 
   When the color adjustment sliding bar  2978  is moved to the right, for example, the DTV  2530  is set to display green strong. When the bar is moved to the left, purple is displayed strong. The application generates an operand of the PHASE CONTROL command in accordance with a position of the color adjustment sliding bar  2978 , and transmits the operand to the DTV  2530 . 
   When the color density adjustment sliding bar  2980  is moved to the right, for example, the color of the DTV  2530  is set to become deep. The application generates an operand of the CHROMA CONTROL command in accordance with a position of the color density adjustment sliding bar  2980 , and transmits the operand to the DTV  2530 . 
   When the resolution adjustment sliding bar  2982  is moved to the right, for example, the contour compensating function is set strong in the display surface of the DTV  2530 , and the resolution of the display surface is set high. Moreover, when the resolution adjustment sliding bar  2982  is moved to the left, the contour compensating function is set weak, and the resolution of the display surface is lowered. 
   The application generates an operand of the APERTURE CONTROL command in accordance with a position of the resolution adjustment sliding bar  2982 , and transmits the operand to the DTV  2530 . 
   While observing the DTV  2530 , or the preview screen  2972 , the operator of the application adjusts the above-described plurality of adjustment bars  2974  to  2982  to adjust the image quality of the DTV  2530 . 
   After the operator performs the image quality adjustment of the DTV  2530 , the computer application generates a command of the DVCR  2556  corresponding to the image quality setting of the DTV  2530  to transmit the command to the DVCR  2556 . 
   For example, when the brightness is adjusted by the application, the GAIN CONTROL command and GAMMA CONTROL command to the video camera sub-unit in the DVCR  2556  are generated corresponding to the generated BRIGHTNESS command to the DTV  2530 , and transmitted to the DVCR  2556 . 
   Moreover, in the case where the brightness is adjusted as described above, after the automatic exposure mode is set by the AE MODE CONTROL command, exposure may be set in accordance with the set brightness by the AE LOCK CONTROL command. 
   Furthermore, when the tint is adjusted by the application, the application generates the WHITE BALANCE CONTROL command for the video camera unit in response to the generated PHASE CONTROL command for the DTV  2530 , and transmits the command to the DVCR  2556 . 
   Additionally, when the color density is adjusted by the application, the application generates the GAIN CONTROL command of the color-difference signal for the video camera unit in response to the generated CHROMA CONTROL command for the DTV  2530 , and transmits the command to the DVCR  2556 . 
   Moreover, when the resolution is adjusted by the application, the application generates the APERTURE CORRECTION CONTROL command for the video camera unit in response to the generated APERTURE CONTROL command for the DTV  2530 , and transmits the command to the DVCR  2556 . 
   In the DVCR  2556 , by the received camera command, the system controller  2576  in the DVCR  2556  allows the video processing unit  2562  to perform a processing corresponding to the command, and stores the image quality setting information in the EEPROM  2588 . By the above-described operation, the DVCR  2556  adjusts a photographing image quality, and additionally holds the image quality setting information even if the power supply to the DVCR  2556  is cut off. 
   By the above-described operation, the communication device in the embodiment can set the image quality of the DTV  2530  or another image output device, and can additionally reflect the content of the image quality setting in the photographing image quality setting of the DVCR  2556  or another photographing device and store the content. 
   Moreover, since the photographing image quality of the DVCR  2556  or another photographing device can be set on the DTV  2530  or another image output device, different from the prior art, the menu incorporated in the photographing device does not have to be used, and operating properties and visibility can remarkably be enhanced. 
   Furthermore, While the photographing device of the embodiment is connected to the 1394 bus, the image quality can be set. Therefore, the effect of the image quality adjustment can effectively be recognized easily. Additionally, the image output device of the embodiment is not limited to the DTV  2530  and needless to say, various image display devices such as a liquid crystal monitor, plasma display, and another monitor device can be used. 
   Moreover, there is a demerit that a stand-by time is lengthened by a printing time, but needless to say, a printer, copying machine and the like can be used. 
   Furthermore, the photographing device of the embodiment can be applied not only to the camera incorporating type VCR and another video camera but also to a still video camera, digital camera and any other photographing device. Moreover, the device is not limited to the camera device, and needless to say, the device can be applied to a film scanner, flat bed scanner or another scanner device, or to a draft scanner section of the copying machine or the like. 
   Moreover, the control node of the embodiment is not limited to the computer or another electronic calculator, and needless to say, another apparatus may be used. Furthermore, the control node of the embodiment does not have to be an independent apparatus, and needless to say, either the image output device or the photographing device may be constituted to operate as the control node. 
   Also, though the embodiment is explained according to an example, that is data communication system based upon the IEEE 1394 standard, the present invention can be applied to other data communication system. That is, it is possible to apply to data communication systems which can utilize a data communication method assuring real-time data transfer of the moving image data etc. as Isochronous transfer system and a data communication method transferring necessary information to a designated device without preventing the real-time data communication as Asynchronous transfer system. 
   Other Embodiments of the Invention 
   The present invention may be applied to a system constituted of a plurality of apparatuses (e.g., host computer, interface apparatus, reader, printer and the like), or to a device constituted of one apparatus. 
   Moreover, in order to operate various devices to realize the above-described function of the embodiment, the program code of the software for realizing the function of the embodiment is supplied to a device connected to the various devices, or to the computer in the system, so that the various devices are operated in accordance with the program stored in the system or in the computer of the device (CPU or MPU). Such implementation is also included in the category of the present invention. 
   Furthermore, in this case, the program code itself of the software realizes the function of the embodiment, and the program code itself, and means for supplying the program code to the computer, e.g., the storage medium with the program code stored therein constitute the present invention. As the storage medium for storing the program code, for example, a floppy disc, hard disc, optical disc, optical magnetic disc, CD-ROM, magnetic tape, non-volatile memory card, ROM, or the like can be used. 
   Moreover, when the computer executes the supplied program code, the above-described function of the embodiment is realized. Additionally, the program code cooperates with OS (operating system) operated in the computer or another application software to realize the function of the embodiment. Needless to say, such program codes are included in the embodiment of the present invention. 
   Furthermore, after the supplied program code is stored in a memory provided in a function expansion board of a computer or a function expansion unit connected to the computer, based on an instruction of the program code, CPU or the like provided in the function expansion board or the function expansion unit performs a part or the whole of the actual processing, and by the processing the above-described function of the embodiment is realized. Needless to say, this case is also included in the present invention. 
   In the second embodiment, as described above, when various data are transmitted/received among a plurality of terminal devices connected via the data communication bus to perform a predetermined processing, the image quality adjustment data is transmitted via the data communication bus, and operation is performed in accordance with the image quality adjustment data in the terminal device which has received the image quality adjustment data. Therefore, the image quality setting of the image display device can be remote-operated, and the operating properties and visibility can remarkably be enhanced. Moreover, according to other characteristics of the present invention, the content of the image quality setting can be reflected on the side of the set terminal device. Furthermore, according to other characteristics of the present invention, the content of the image quality setting can be stored in the storage means. 
   Moreover, according to the second embodiment, since the image quality adjustment data transmitted via the data communication bus is received to change the photographing image quality, the content of the image quality setting of the image display device can be reflected in the photographing image quality setting of the photographing device. Furthermore, according to other characteristics of the present invention, the content of the photographing image quality setting can be stored in the storage medium. Thereby, without using the menu or the like incorporated in the photographing device, the photographing image quality can be set by the remote operation, and the operating properties and visibility of the photographing device can remarkably be enhanced. 
   Moreover, according to the second embodiment, while the photographing device is connected to the 1394 bus, the image quality setting can be performed, so that the effect of the image quality adjustment can easily be recognized.