JPH09116802A - Image transmission apparatus and image transmission method - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To change the optimum gradation or resolution of image data selectively according to the image area when changing the shooting position or focal length of a camera, which enables far-end control. An image transmission device with good followability and excellent operability, and
It is an object of the present invention to provide an image transmission method with excellent operability by optimizing the amount of transmission data. An imaging camera (1) and a driving unit (2) for manually or automatically changing a shooting position and a focal length of the camera (1).
And an image codec unit 3 that converts an image captured by the camera 1 into digital data composed of a plurality of bit data, compresses and encodes the digital data, and a shooting position or focus of the camera 1. A shooting change detection unit 3a that detects that the distance has changed, and a fixed bit selection unit 3b that sequentially selects and fixes bit data from at least one lower order of the digital data when the shooting position or the focal length of the camera 1 is changed. I have prepared.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transmission device for transmitting image data using a digital communication line or the like,
In particular, the present invention relates to an image transmission device and an image transmission method used for transmitting and receiving image data of an electronic conference device.

[0002]

2. Description of the Related Art In recent years, the introduction of electronic conferencing equipment has increased due to the widespread use of ISDN lines. In an image transmission device used in an electronic conference device, a control signal multiplexed with a compressed and encoded image or audio signal is used to remotely control an image pickup camera of a transmission terminal from a reception terminal called a far end control. Is being done.

[0003] A conventional image transmission apparatus will be described below. FIG. 10 is a block diagram showing the configuration of a conventional image transmission device. FIG. 10 shows an example of a conventional electronic conferencing apparatus capable of communicating at two points, that is, terminal A and terminal B. 21A
Is a conventional terminal A image transmission device, and 21B is a conventional terminal B image transmission device. 1, 1'is an image pickup camera for photographing an image, 2, 2'is a drive unit for changing the photographing position and focal length of the cameras 1, 1 ', and 3 and 3'is for compressing and expanding a digitally converted image. , Image codec circuits for encoding and decoding, and 4 ', 4'are image display devices comprising monitors for displaying images output from the image codec circuits 3, 3'from other terminals at other points. Is the driving unit 2 for the direction, elevation angle, focal length, etc. of the cameras 1, 1 '.
Operation circuits controlled by 2 ', 6, 6'are control signal circuits for controlling cameras 1, 1'of other terminals at other points through a digital communication line 13 described later, 7,
7'is a microphone for inputting voice, 8 and 8'is a microphone amplifier circuit which is connected to the microphones 7 and 7'of its own terminal and amplifies the audio signal, and 9 and 9'is communication of the audio signal with the partner terminal at another point. A voice codec circuit for compressing, decompressing, encoding, and decoding a voice to be output, 10 and 10 'are speakers for outputting a voice signal, and 11 and 11' are for amplifying a voice signal from a partner terminal and ringing the speakers 10 and 10 '. Speaker amplifier circuit, 1
Reference numerals 2 and 12 'are digital communication lines by multiplexing the image signals encoded by the image codec circuits 3 and 3'and the audio codec circuits 9 and 9', the audio signals and the control signals generated by the control signal circuits 6 and 6 '. Multiplexing circuit connected to 13,
Reference numeral 13 is a digital communication line such as an ISDN line.

The operation of the conventional image transmission apparatus configured as described above will be described below. First, for data reception, a compressed and encoded image signal, which is connected to a terminal at another point through the digital communication line 13,
The voice signal and other digital signals are multiplexed by the multiplexing circuit 12 'of the remote terminal, and the digital signal sent through the digital communication line 13 is the multiplexing circuit 12 of the local terminal.
, And is separated into an image signal, an audio signal and a control signal which are respectively compressed and encoded. After that, the compressed and encoded image signal is expanded and decoded by the image codec circuit 3 to be restored to the original image signal. The restored image signal is displayed on the image display device 4. on the other hand,
The audio signal separated by the multiplexing circuit 12 is expanded and decoded by the audio codec circuit 9 to be restored to the original audio signal. The speaker 7 is sounded by the speaker amplifier circuit 11 from the restored audio signal.

Next, regarding data transmission, the operation circuit 5 controls the direction, elevation angle, focal length, etc. of the camera 1 through the drive unit 2, and the image signal picked up by the camera 1 is the image codec circuit 3. To be compressed and encoded. On the other hand, the voice signal of the terminal captured by the microphone 7 and amplified by the microphone amplifier 8 is the voice codec circuit 9
Then, the electronic conference is established by being compressed and encoded, multiplexed by the multiplexing circuit 12 with the image signal and the like, and connected to the digital communication line 13. At this time, when operating the direction, the elevation angle, the focal length, etc. of the camera 1'of the partner terminal, the control circuit generated by the control signal circuit 6 by the operation circuit 5 is multiplexed by the multiplexing circuit 12 to be transmitted to another point. The signal is sent out, the control signal is separated again by the multiplexing circuit 12 'of the remote point terminal, and the control signal circuit 6'adds the control signal to the drive unit 2'of the camera 1'. Be seen.

[0006]

In this image transmission apparatus, when the image pickup camera of the transmission terminal is operated by the reception terminal called the far end control of the camera of the electronic conferencing apparatus using a digital communication line such as an ISDN line, The camera is operated while viewing the image of the other terminal generally sent. At this time, when the remote control is performed by the control signal multiplexed with the compressed and encoded image and audio signals, the transmission amount of data per unit time is limited, so that image discontinuity and image delay occur. During the operation of the camera, even though it is difficult to distinguish the image or the camera is in the proper position, the movement of the camera is stopped too late and the camera goes too far. Cause trouble. For this reason, there is a demand for an image transmission device that is excellent in operability and has good followability when the camera is operated while viewing the image of the other party.

According to the present invention, when changing the photographing position or focal length of a camera in image transmission, the optimum gradation or resolution of image data is selectively variable according to the image area to improve image visibility. At the same time, an image transmission device that is capable of far-end control and has excellent operability and excellent operability, and an image with excellent operability that optimizes the amount of data to be transmitted and optimally transmits the image An object is to provide a transmission method.

[0008]

In order to solve this problem, an image transmission apparatus of the present invention comprises a camera for imaging, a drive unit for manually or automatically changing the shooting position and focal length of the camera, and a camera. An image transmission device including an image codec unit that converts an image captured from a digital data composed of a plurality of bit data, compresses and encodes the data,
A shooting change detection unit that detects that the shooting position or focal length of the camera has changed, and a fixed bit selection unit or digital data that fixes at least one bit data when the shooting position or focal length of the camera changes. A data hold unit for holding at least one or more predetermined time intervals,
When changing the shooting position, focal length, etc. of the camera, the optimum gradation or resolution of the image data can be selectively changed according to the image area to improve the visibility of the image and the far-end computer. It is configured so as to perform image compression, which can be rolled.

Thus, it is possible to prevent an increase in the amount of image data to be transmitted due to an increase in image change while changing the photographing position or focal length of the camera. That is, it can automatically change to the minimum gradation and resolution to recognize the image,
It is possible to improve the image quality and frame rate of image compression and decompression per unit time, and to perform image compression capable of far-end control.

Further, according to the image transmission method of the present invention, the photographing position and the focal length of the photographing camera are changed manually or automatically, and the image photographed by the camera is converted into digital data consisting of a plurality of bit data. An image transmission method that compresses and encodes digital data and transmits the data over a communication line. When a change in the shooting position of the camera is detected and the shooting position of the camera is changed, the bit of the digital data is changed. At least one data is fixed, or an image signal from a camera or digital data of the image signal is held for a predetermined time.

As a result, when changing the photographing position or focal length of the camera, the optimum gradation or resolution of the image data can be selected and varied according to the image area to improve the visibility of the image and the far-end computer. It is possible to perform image compression capable of Toroll. As a result, the amount of data to be transmitted can be optimized, the optimal data transmission of the image can be performed, and the operability can be improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image transmission device according to claim 1 of the present invention is an image capturing camera, a drive unit for manually or automatically changing the image capturing position or focal length of the camera, and an image captured by the camera. An image transmission device including an image codec unit for converting an image into digital data composed of a plurality of bit data, compressing and encoding the image data, and a shooting change detecting a change in a shooting position or a focal length of a camera. The configuration includes a detection unit and a fixed bit selection unit that fixes at least one bit data when the shooting position or the focal length of the camera changes, and changes the shooting position or the focal length of the camera. Medium, it is possible to prevent an increase in the amount of image data to be transmitted due to an increase in image change. That is, the gradation of the image can be automatically changed, and the image quality and the frame rate of image compression and expansion per unit time can be improved.

According to the image transmission device of the second aspect, in the first aspect, the fixed bit selection unit is configured to sequentially select the bit data to be fixed from the lower order of the digital data. It can be variably controlled according to the image transmission amount.

According to a third aspect of the present invention, in the image transmission apparatus according to the first or second aspect, the photographing change detecting section detects the moving speed of the photographing position of the camera, and the fixed bit selecting section responds to the moving speed. Since the configuration is such that the number of fixed bit data is selected, optimum automation of data transmission can be realized.

An image transmission device according to a fourth aspect is the image transmission device according to any one of the first to third aspects, in which the photographing change detection unit is
The fixed bit selection unit detects the focal length of the camera and selects the number of fixed bit data according to the focal length of the camera. The fixed number of bit data is selected according to the focal length of the camera. Thus, it is possible to realize the optimum automation of data transmission in consideration of the fact that the image change amount varies depending on the size of the region to be photographed.

According to a fifth aspect of the present invention, there is provided the image transmission device according to any one of the first to fourth aspects, in which the photographing change detecting section comprises:
Detects the amount of change in the focal length of the camera per unit time,
The fixed bit selection unit is configured to select the number of bit data to be fixed according to the change amount, and the shooting change detection unit detects the change amount of the focal length of the camera per unit time and selects the fixed bit. By selecting the number of bit data to be fixed according to the change amount, the unit can adapt not only to the change of the shooting position but also to the image change due to the change of the shooting range.

According to another aspect of the image transmission device of the present invention, a drive control unit for manually or automatically changing a photographing position or a focal length of the camera, and an image picked up by the camera are converted into digital data composed of a plurality of bit data. An image transmission device including a codec unit for converting, compressing, and encoding,
A configuration including a shooting change detection unit that detects that the shooting position of the camera has changed, and a data hold unit that holds at least one digital data at a predetermined time interval when the shooting position of the camera has changed, Therefore, it is possible to prevent an increase in the amount of image data to be transmitted due to an increase in image change during the change of the photographing position or the focal length of the camera. That is, the resolution of the image can be automatically changed, and the image quality and the frame rate of image compression and expansion per unit time can be improved.

According to a seventh aspect of the present invention, in the image transmission apparatus according to the sixth aspect, the data holding unit holds the video signal from the camera by using a hold clock that is an integral multiple of a sample clock cycle. Thus, the image resolution can be variably controlled according to the image transmission amount.

According to an eighth aspect of the present invention, in the image transmission apparatus according to the sixth or seventh aspect, the photographing change detection unit detects the moving speed of the photographing position of the camera, and the data hold unit changes the photographing position of the camera. Since the predetermined time interval is changed according to the speed, optimum automation of data transmission can be realized.

An image transmission device according to a ninth aspect is the image transmission device according to any one of the sixth to eighth aspects, wherein
The data hold unit detects the focal length of the camera and
The configuration is such that the predetermined time interval is changed according to the focal length of the camera, and in consideration of the fact that the amount of image change varies depending on the size of the area to be photographed, the optimal automation of data transmission is possible. Can be realized.

In the image transmission apparatus according to a tenth aspect of the present invention, in any one of the sixth to ninth aspects, the photographing change detection unit detects the amount of change in the focal length of the camera per unit time, and holds the data. The unit is configured to change the predetermined time interval according to the amount of change, and can be adapted not only to the change of the photographing position but also to the image change due to the change of the depth of focus.

According to the image transmission device of the eleventh aspect, in any one of the first to tenth aspects, the fixed bit data or the held digital data is restricted according to the area of the image to be picked up. It is configured as
It is possible to reduce the gradation and resolution only in relatively unimportant image areas (for example, peripheral areas) within the shooting range of a camera, etc., and to increase image compression, and for important image areas (for example, central areas) The image characteristics can be improved without lowering the tonality and resolution. That is, the amount of data to be transmitted can be more reliably optimized, the region of image quality to be transmitted can be changed, and flexibility can be given to selection of fixed bit data or held digital data.

The image transmission device according to a twelfth aspect is the image transmission device according to the eleventh aspect, wherein the area of the image to be fixed or held is moved according to the moving speed and moving direction of the photographing position of the camera. , The image area with variable image characteristics can be variably controlled according to the image transmission amount,
Optimal automation of data transmission can be realized.

According to a thirteenth aspect of the present invention, in the eleventh or twelfth aspect, the size of the area of the image that is fixed or held is changed according to the moving speed and the size of the focal length of the camera. With this configuration, the image area with variable image characteristics can be variably controlled according to the image transmission amount, and optimum automation of data transmission can be realized.

In the image transmission method according to the fourteenth aspect, the photographing position and the focal length of the camera for photographing are manually or automatically changed, and the image photographed by the camera is converted into digital data composed of a plurality of bit data. Then, it is an image transmission method that compresses and encodes digital data and transmits it through a communication line, and detects a change in the shooting position of a camera,
When the shooting position of the camera is changed, at least one bit data of the digital data is fixed, and the amount of image data to be transmitted is increased due to the increase of the image change during the change of the shooting position or the focal length of the camera. The increase can be prevented. That is, the gradation of the image can be automatically changed, and the image quality and the frame rate of image compression and expansion per unit time can be improved.

In the image transmitting method according to the fifteenth aspect, the photographing position and the focal length of the camera for photographing are manually or automatically changed, and the image photographed by the camera is converted into digital data consisting of a plurality of bit data. Then, it is an image transmission method that compresses and encodes digital data and transmits it through a communication line, and detects a change in the shooting position of a camera,
When the position of the camera is changing, the image signal from the camera or the digital data of the image signal is configured to be held for a predetermined time, and is transmitted due to an increase in the image change while changing the shooting position or focal length of the camera. It is possible to prevent an increase in the amount of image data. That is, the resolution of the image can be automatically changed, and the image quality and the frame rate of image compression and expansion per unit time can be improved.

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the arrangement of an image transmission apparatus according to the first embodiment of the present invention. 1A, 1B
Is an image transmission apparatus according to the first embodiment of the present invention. 1, 1'is a camera, 2, 2'is a driver, 3, 3'is an image codec circuit, 4, 4'is an image display device, 5,
5'is an operation circuit, 6, 6'is a control signal circuit, 7, 7'is a microphone, 8, 8'is a microphone amplifier circuit, 9 and 9'is a voice codec circuit, 10 and 10 'is a speaker, 11, 1
1'is a speaker amplifier circuit, 12 and 12 'are multiplexing circuits, and 13 is a digital communication line. Since these are the same as those in the conventional example, the same reference numerals are given and description thereof is omitted. The difference from the conventional example is that the gradation of the image can be changed automatically, and it has the effect of improving the image quality and frame rate of image compression and decompression per unit time, and detects that the shooting position of the camera has changed. Shooting change detection unit 3a, 3
a ', and fixed bit selection units 3b, 3b' for fixing at least one bit data of a digital signal which is image data obtained from the camera when the photographing position of the camera changes, that is, moves. ing. or,
The fixed bit selection units 3b and 3b 'are configured to sequentially select the bit data to be fixed from the lower order of the digital data, and to select the number of fixed bit data according to the moving speed of the cameras 1 and 1'. Controlled by.

An electronic conferencing apparatus using the image transmitting apparatus according to the first embodiment of the present invention configured as described above,
The operation will be described below. First, the operation of an ordinary electronic conferencing apparatus is similar to the conventional example, in which digital signals such as compressed and encoded image signals, voice signals, and control signals are transmitted and received through the digital communication line 13 connected to the partner terminal at another point. To be done. In the case of reception, the multiplexing circuit 1 of the partner terminal at another point
The digital signal multiplexed at 2'is sent through the digital communication line 13 and separated by the multiplexing circuit 12 into each image signal, audio signal and control signal. The image signal is expanded and decoded by the image codec circuit 3 and restored to the original image signal. The restored image signal is displayed on the image display device 4. The audio signal separated by the multiplexing circuit 12 is decoded and expanded by the audio codec circuit 9 to be restored to the original audio signal. This restored audio signal is output to the speaker 10 by the speaker amplifier circuit 11.
To be played through. On the other hand, in the case of transmission, the image data from the camera 1 is sent to the image codec circuit 3 and compressed,
Encoded. The voice signal of the terminal captured by the microphone 7 and amplified by the microphone amplifier circuit 8 is sent to the voice codec circuit 9, compressed and encoded, and multiplexed by the multiplexing circuit 1.
2 is multiplexed and transmitted via the digital communication line 13 to the partner terminal at another point. As a result, the electronic conference is established. At this time, when operating the direction, elevation angle, focal length, etc. of the camera 1 ′ of the partner terminal, the control signal generated by the control signal circuit 6 is used by the operating circuit 5 to duplicate the control signal.
Multiplexing with 1 and sending to another point, multiplexing circuit 1
At 2 ', the control signal is separated again, and the control signal circuit 6'at another point is applied to the driving section 2'of the camera 1'to operate the camera 1'and perform the camera operation by the far end control. That is, the control signal from the operation circuit 5 at a remote place controls the shooting position such as the direction and elevation angle of the camera 1 ', the focal length, etc. by the drive unit 2', and the image signal picked up by the camera 1'is fixed bit selection. Sent to section 3b '.
Here, the bits of the image signal are fixedly controlled.

The fixed bit selection unit 3b (3b ') of the image transmission apparatus of the first embodiment of the present invention which operates as described above.
The circuit configuration will be described below. FIG. 2 is a circuit diagram showing a configuration example of a fixed bit selection unit in the image transmission apparatus of the first embodiment of the present invention, and FIG. 3 is a subordinate of image data in the image transmission apparatus of the first embodiment of the present invention. 3 is a schematic diagram showing an image area in which the bit data of FIG. In FIG. 2, M is a camera movement signal, and the camera movement signal M is set to ON when the photographing change detection unit 3a moves the photographing position of the camera 1. or,
S1 and S2 are bit number switching signals, and D7 to D0 are image data in which video signals are digitized by an A / D converter. Here, by selecting one of the bit number switching signals S1 and S2 from the photographing change detection unit 3a,
The bit data fixed among the image data D7 to D0 can be changed from lower bits to 2 bits or 3 bits. Further, H is a horizontal area signal, V is a vertical area signal,
An area smaller than the entire screen area is a horizontal area signal H and a vertical area signal V due to a combination of a counter that counts an image sample clock and a horizontal synchronization signal, and a comparator.
Is formed as an active signal of.

In FIG. 3, A is an area of the image data other than the B area where the lower bits of the image data are fixed, and B is a rectangular area through which the image data passes,
As signals representing these areas, the shooting change detection unit 3a outputs the horizontal area signal H and the vertical area signal V to the fixed bit selection unit 3b. Here, the region B is calculated by taking the logical product of the horizontal region signal H and the vertical region signal V, and the rest is obtained as the region A.

The operation of the fixed bit selection unit 3b of the image transmission apparatus of the first embodiment of the present invention configured as above will be described below. The camera movement signal M, the bit number switching signals S1 and S2, the horizontal area signal H, and the vertical area signal V are input to the fixed bit selection unit 3b shown in FIG. 2, and each gate is operated. Here, when the image data D7 to D0 consisting of the A / D-converted 8-bit digital data from the camera 1 is input, the AND gate 14 is opened only in the area B in FIG. It is input to the image codec circuit 3. In the surrounding area A, the AND gate 14 of the lower bits of the image data D7 to D0 is closed and a part of the lower bits of the image data D7 to D0 is fixed, and the image data D7 to The gradation change of D0 is reduced and is input to the image codec circuit 3. Therefore, as the amount of data change in the surrounding area A is reduced, the total amount of data to be transmitted is reduced, the compression and decompression operations are speeded up, and the image quality and frame rate are improved. If the position of the camera 1 is fixed after controlling the shooting position of the camera 1, the AND gate 14 of the fixed bit selection unit 3b opens and all bits of image data pass through as they are, and the gradation of the image data becomes normal again and the image quality is improved. Will recover.

As described above, according to the present embodiment, when the camera is moved, the gradation of the periphery of the image of the terminal to be controlled is slightly lost, but the original purpose is to smoothly move the camera position. Since it is easy and the image of the central part is clear, the operability can be greatly improved.

Although the fixed bit selection unit 3b in the present embodiment has been described as a gate circuit, the same effect can be obtained even if a switch circuit, a latch circuit, a data selector circuit or the like is used instead of the gate circuit. It's obvious.

Further, the bit number switching signal S1, in FIG.
Although S2 has been described as a signal for changing the fixed lower bit number of the image data, the bit number switching signals S1, S2.
Using the camera speed signal, an appropriate gradation can be selected according to the amount of movement of the camera per unit time.
As a result, as the moving speed of the camera increases,
Although the amount of change in image data increases, the amount of communication data can be optimally controlled without increasing the amount of communication data. Especially,
Even if the amount of movement of the camera per unit time is large, compression,
The decompression operation is quick, deterioration of the central image is suppressed, and the frame rate can be improved. Further, when the moving speed of the camera is extremely high, it is possible to fix the lower bits of the image data when moving the camera for the entire transmission image area without performing the gate operation by the horizontal area signal H and the vertical area signal V. , The total amount of data to be transmitted is further reduced.

Even if the amount of movement of the camera per unit time is the same, if the focal length of the lens used is long, the amount of change per unit time of the image to be picked up when the camera is moving increases and the amount of communication data increases. Also, by switching the bit number switching signals S1 and S2 of the gate operation shown in FIG. 2 according to the focal length of the camera lens, the fixed lower bit number is made variable, and an appropriate data amount is obtained according to the focal length of the camera lens. Can be selected, the operation of compressing and expanding the image data is quick, and the image quality and frame rate can be improved. When using a zoom lens with a continuously variable focal length as the camera lens, a shooting change detection unit or the like detects the amount of change in the focal length of the camera lens per unit time and is fixed according to the amount of change. By changing the number of bit data to be changed stepwise by the fixed bit selection unit, the camera operation can be performed more effectively.

(Second Embodiment) An image transmission apparatus according to a second embodiment of the present invention will be described below with reference to the drawings. FIG. 4 is a circuit diagram showing a configuration example of a data hold unit of the image transmission device according to the second embodiment of the present invention. The configuration of the image transmission device according to the second embodiment of the present invention is substantially the same as the block diagram shown in FIG. 1 of the first embodiment. The difference from the first embodiment is that the image resolution can be changed automatically, and the image compression and decompression image quality per unit time and the frame rate are improved.
In place of the fixed bit selection section 3b for fixing the bit of No. 3, the data hold section 3c for changing the sampling rate of the image data is configured. The data hold unit 3c
The latch circuit 15 and the flip-flop circuit (F / F) 16 that make the predetermined time interval an integral multiple of the sample clock of the image are configured to hold the bit data of the image data D7 to D0 at the predetermined time interval. In addition, the camera movement signal M, the latch multiple switching signals S1 and S2, and the image sample clock Ck which is a sample clock for A / D converting the image signal are input to the data hold unit 3c from the photographing change detection unit 3a. . When the shooting change detection unit 3a detects that the shooting position of the camera has changed, a clock obtained by multiplying the image sample clock Ck by the flip-flop circuit 16 by an integer is used as a latch clock for the latch circuit 15 of the data hold unit 3c. The image data D7 to D0 are input and held. Further, it is not necessary to hold all the bit data of the image data D7 to D0 held by the data holding unit 3c, and at least one bit data may be variably set depending on the limitation of the communication data amount.

The operation of the data hold unit 3c of the image transmission apparatus according to the second embodiment of the present invention having the above-described structure will be described below. In FIG. 4, the latch circuit 15 latches image data with a clock that is an integral multiple of the image sample clock Ck. That is,
The multiple of the image sample clock Ck to be latched is switched by the camera movement signal M, the latch multiple switching signals S1 and S2, and the horizontal area signal H and the vertical area signal V shown in FIG. The camera operation signal M is input, and the area B in FIG.
Since it is directly latched only by the image sample clock Ck, the image data D7 to D0 as it is passes through. In the area A around the area B, the data is latched by a clock that is an integral multiple of the image sample clock Ck according to the bit switching signals S1 and S2. As a result, the image data is held with the time data that is an integral multiple of the image sample clock Ck, so that the resolution of the image data becomes coarse. Therefore, since the amount of change in the data in the area A is small, the total amount of data to be transmitted is small, the compression and decompression operations are quick, and the image quality and the frame rate can be improved. In particular, although the resolution of the image of the terminal to be controlled is slightly lost, the smooth movement of the camera position, which is the original purpose, can be facilitated and the operability can be improved. If the camera position is fixed after controlling the image position of the camera, all bits of the image data are latched by the latch circuit 15 at the image sample clock Ck, the resolution becomes normal again, and the image quality is restored.

In the present embodiment, the description has been given using the latch circuit 15, but a latch circuit built in or added to the latch circuit of the A / D converter, the memory circuit, the codec circuit or the like may be used. It is obvious that the same effect can be obtained.

Further, the latch multiple switching signal S in FIG.
Although 1 and S2 have been described as signals that change the multiple of the clock that latches the image data, the imaging change detection unit 3
a detects the moving speed of the shooting position of the camera, and the data hold unit 3c uses the latch multiple switching signals S1 and S2 as the camera speed signal in accordance with the changing speed of the shooting position of the camera. An appropriate resolution of the image data can be selected according to the amount of movement per unit time and the like, the operation of compressing and decompressing the image data becomes quick, and the image quality and the frame rate can be optimized. Further, it is possible to latch the image data when the camera is moved in the entire transmission image area without performing the gate operation by the horizontal area signal H and the vertical area signal V. In this case, it is clear that the amount of change in the image data is further reduced, the compression and decompression operations are quick, and the image quality and frame rate are improved.

Further, the photographing change detection section 3a detects the focal length of the camera lens, and the data hold section 3c switches the latch multiple switching signals S1 and S2 shown in FIG. 4 according to the focal length of the camera lens. By changing the multiple of the clock that latches data, you can select the appropriate amount of data according to the focal length of the lens used by the camera, optimize the amount of data in the communication system, and improve the image quality and frame rate. be able to. Furthermore, when a zoom lens having a continuously variable focal length is used as the camera lens, the photographing change detection unit 3a detects the amount of change in the focal length of the camera lens per unit time, and according to the amount of change. A more effective camera operation can be realized by continuously or stepwise varying or interlocking a multiple of the clock with the data hold unit 3c.

(Third Embodiment) An image transmission apparatus according to a third embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is a waveform diagram showing timings of a horizontal area signal and a vertical area signal when the photographing position of the camera of the image transmission apparatus according to the third embodiment of the present invention is moved to the right, and FIG. It is a waveform diagram which shows the timing of a horizontal area signal and a vertical area signal at the time of moving the imaging position of the camera of the image transmission apparatus in 3 embodiment to the left.
As the horizontal area signal H and the vertical area signal V, the same signals as the horizontal area signal H and the vertical area signal V in FIG. 2 of the first embodiment are used. In the first and second embodiments, the horizontal area signal and the vertical area signal for performing the gate operation as shown in FIGS. 5 and 6 are offset in the moving direction of the camera from the center of the timing of the gate signal, and the camera moves in the future. Even if there is a delay in image arrival due to communication system and image compression / decompression without degrading the gradation or resolution of the image to be attempted, the deviation of the image center when the camera control is stopped is more significant. In FIG. 5, the position of the camera can be controlled quickly, and in FIG. 5, when the camera moves to the right, the area B in which the gradation or resolution does not deteriorate in the entire screen area A is offset to the right. It is shown that. Similarly, FIG. 6 shows that the area where there is no deterioration in gradation or resolution is offset to the left while the camera is moved to the left.
It is also clear that a similar configuration is possible when moving the camera up and down.

As described above, according to the present embodiment, when the amount of change in image data is reduced, an image having a high gradation or resolution is sent to the image to which the camera will move in the future. Thus, the position control of the camera can be performed quickly.

(Fourth Embodiment) An image transmission apparatus according to a fourth embodiment of the present invention will be described below with reference to the drawings. FIG. 7 is a waveform diagram showing variable control of the timing of the horizontal area signal and the vertical area signal of the image transmission apparatus according to the fourth embodiment of the present invention, and FIG. 8 is the fourth embodiment of the present invention.
FIG. 9 is a waveform diagram showing variable control of the timing of the horizontal region signal and the vertical region signal according to the moving speed of the camera of the image transmission device in the embodiment in the leftward movement, and FIG. FIG. 11 is a waveform diagram showing variable control of timing of horizontal area signals and vertical area signals according to the moving speed of the camera of the image transmission device in the fourth embodiment when moving to the right in the shooting position. Similar to the third embodiment, the horizontal area signal H and the vertical area signal V are the same as those in the first embodiment shown in FIG.
Signals similar to the horizontal area signal H and the vertical area signal V in are used. By changing the comparator values of the horizontal area signal H and vertical area signal V generation circuits by combining a counter and a comparator for performing a gate operation, as shown in FIGS. It is possible to change the area width without deterioration, and by selecting an appropriate amount of data according to the amount of movement of the camera per unit time, the amount of data in the communication system decreases and further compression,
This has the effect of speeding up the decompression operation and improving the image quality and frame rate. Here, the explanatory diagram is created by changing both the horizontal and vertical areas, but it is also possible to change either the horizontal or vertical area. Up and down,
Obviously, it is possible to change one region.

As described above, according to the present embodiment, by varying the data area for fixing or holding the image data, the optimum image according to the data transmission amount of the communication line can be transmitted more flexibly. be able to.

In the first to fourth embodiments, the far-end control of the camera of the electronic conferencing apparatus using the ISDN line has been described as an example, but a monitoring system for transmitting using a normal dedicated communication line or a local area network or the like. It is also possible to apply such as. Also, the remote operation of mechanically driving the camera has been described as an example. However, even in the case of the manual operation circuit or the operation of the drive unit, the camera movement signal is detected by using the detection switch provided in the drive unit of the camera when the camera is moved. Can be generated and the same operation can be performed, the image quality and frame rate of the image of the partner terminal when the camera is moved are improved, and the same operation can be performed other than the remote operation.

[0047]

As described above, according to the image transmitting apparatus of the present invention, the amount of data to be transmitted during the change of the camera photographing position or the focal length is reduced, and the minimum gradation and resolution are required for recognizing the image. It is possible to set the data and area, and it is possible to obtain an advantageous effect that the amount of data to be transmitted is optimized and the image compression and decompression image quality per unit time and the frame rate are excellent in operability. In particular, while improving the image when moving the camera and improving the visibility, it also improves the image when operating the camera, and is said to have excellent operability, which can be used for electronic conference devices that can smoothly control the far end of the camera. An advantageous effect is acquired.

Further, according to the image transmission method of the present invention, the optimum gradation and resolution for recognizing an image can be set according to the area of the image data, the amount of data to be transmitted is optimized, and the image compression is performed. The advantageous effect of excellent operability for improving the image quality and frame rate of decompression can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an image transmission device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration example of a fixed bit selection unit in the image transmission device according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram showing an image area in which lower-order bit data of image data is fixed in the image transmission device according to the first embodiment of the present invention.

FIG. 4 is a circuit diagram showing a configuration example of a data hold unit of an image transmission device according to a second embodiment of the present invention.

FIG. 5 is a waveform chart showing timings of a horizontal area signal and a vertical area signal when the photographing position of the camera of the image transmission device in the third embodiment of the present invention moves to the right.

FIG. 6 is a waveform diagram showing timings of a horizontal area signal and a vertical area signal when the photographing position of the camera of the image transmission device according to the third embodiment of the present invention moves to the left.

FIG. 7 is a waveform diagram showing variable control of the timing of the horizontal area signal and the vertical area signal of the image transmission device according to the fourth embodiment of the present invention.

FIG. 8 is a waveform diagram showing variable control of the timing of the horizontal area signal and the vertical area signal according to the moving speed when the shooting position of the camera of the image transmission apparatus according to the fourth embodiment of the present invention moves to the left.

FIG. 9 is a waveform diagram showing variable control of the timing of the horizontal area signal and the vertical area signal according to the moving speed when the shooting position of the camera of the image transmission apparatus according to the fourth embodiment of the present invention moves to the right.

FIG. 10 is a block diagram showing a configuration of a conventional image transmission device.

[Explanation of symbols]

 1A, 1B Image transmission device 1 Camera 2 Driving unit 3 Image codec circuit 3a Imaging change detection unit 3b Fixed bit selection unit 3c Data hold unit 4 Image display device 5 Operation circuit 6 Control signal circuit 7 Microphone 8 Microphone amplifier circuit 9 Voice codec circuit 10 Speaker 11 Speaker Amplifier Circuit 12 Multiplexing Circuit 13 Digital Communication Line 14 AND Gate 15 Latch Circuit 16 Flip-Flop Circuit 21A, 21B Conventional Image Transmission Device

Claims (15)

[Claims] 1. A camera for image pickup, a drive unit for manually or automatically changing a shooting position and a focal length of the camera, and an image picked up by the camera is converted into digital data composed of a plurality of bit data. An image transmission device including an image codec unit for compression and encoding, wherein a photographing change detection unit that detects that the photographing position or the focal length of the camera has changed, and the photographing position of the camera or An image transmission apparatus comprising: a fixed bit selection unit that fixes at least one bit data when the focal length is changed. 2. The image transmission device according to claim 1, wherein the fixed bit selection unit sequentially selects the bit data to be fixed from the lower order of the digital data. 3. The shooting change detection unit detects the moving speed of the shooting position of the camera, and the fixed bit selection unit selects the number of the bit data to be fixed according to the moving speed. The image transmission device according to claim 1 or 2, which is characterized in that. 4. The photographing change detection unit detects a focal length of the camera, and the fixed bit selection unit selects the number of bit data to be fixed according to the focal length of the camera. The image transmission device according to any one of claims 1 to 3. 5. The photographing change detection unit detects a change amount of the focal length of the camera per unit time, and the fixed bit selection unit selects the number of the bit data to be fixed according to the change amount. The image transmission device according to any one of claims 1 to 4, wherein: 6. A camera for image pickup, a drive controller for manually or automatically changing the image pickup position and focal length of the camera, and an image picked up by the camera into digital data composed of a plurality of bit data. In the image transmission device including a codec unit that compresses and encodes, a shooting change detection unit that detects that the shooting position of the camera has changed, and the shooting position of the camera has changed, An image transmission device, comprising: a data hold unit that holds at least one or more of the digital data at predetermined time intervals. 7. The image transmission apparatus according to claim 6, wherein the data hold unit holds the video signal from the camera by using a hold clock that is an integral multiple of a sample clock period for sampling the video signal. 8. The photographing change detection unit detects the moving speed of the photographing position of the camera, and the data hold unit changes the predetermined time interval according to the changing speed of the photographing position of the camera. The image transmission device according to claim 6 or 7, characterized in that. 9. The photographing change detector detects the focal length of the camera, and the data hold unit changes the predetermined time interval according to the focal length of the camera. The image transmission device according to any one of 6 to 8. 10. The photographing change detection unit detects the amount of change in the focal length of the camera per unit time, and the data hold unit changes the predetermined time interval according to the amount of change. The image transmission device according to any one of claims 6 to 9, which is characterized in that. 11. The bit data to be fixed or the digital data to be held is limited according to a region of an image to be picked up.
The image transmission device according to any one of 1. 12. The image transmission device according to claim 11, wherein the area of the image to be held is moved according to the moving speed and moving direction of the photographing position of the camera. 13. The size of the held image area is
13. The image transmission device according to claim 11, wherein the image transmission device is changed according to a moving speed and a size of a focal length of the camera. 14. A photographing position or a focal length of an image pickup camera is changed manually or automatically, an image picked up by the camera is converted into digital data composed of a plurality of bit data, and the digital data is compressed. An image transmission method of encoding and transmitting via a communication line, detecting a change of a photographing position of the camera, and changing the photographing position of the camera, the bit data of the digital data is changed. An image transmission method characterized by fixing at least one or more. 15. A shooting position or a focal length of an image pickup camera is changed manually or automatically, an image taken by the camera is converted into digital data composed of a plurality of bit data, and the digital data is compressed, An image transmission method of encoding and transmitting via a communication line, detecting a change in a shooting position of the camera, and when the position of the camera is changed, an image signal from the camera or the image An image transmission method, characterized in that the digital data of a signal is held for a predetermined time.