JP3213216B2 - Video conference equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video conference apparatus for encoding an image signal and an audio signal and outputting the encoded signal to a communication path, and in particular, has a function of automatically controlling the focus and light amount of an electronic camera used for imaging. Related to a video conference device.

[0002]

2. Description of the Related Art Devices called videophones and videoconferencing devices digitize and encode image signals and audio signals obtained by an electronic camera and transmit them to a destination device via a communication line. It reproduces moving images and audio from a signal received from a partner device. Encoding is for reducing the amount of information of an image signal, and is mainly performed by using a high correlation between images of adjacent frames in a plurality of frame images represented by the image signal. For this specific method, for example,
Recommendation H.264 standardized as a moving picture coding method for communication. 261 and the like.

Further, adjustment of a focus position (focus) and a light amount (iris), which are one kind of imaging conditions of an electronic camera, are manually performed by a user of the apparatus or provided in the electronic camera in advance. Further, the correction is performed by an automatic correction function called auto focus and auto iris. These correction functions are for automatically adjusting the focus and iris to an image on a predetermined monitoring area near the center of the imaging screen.

[0004]

Since the change of focus or iris changes the frame image (including the background) obtained by imaging as a whole, the correlation between the frame images at the time of the change is reduced. As a result, the data amount of the encoded moving image signal increases. Further, in videophone and videoconferencing devices, the transfer rate is limited due to the limitation of the capacity of the communication line. Therefore, when the amount of information of the moving image signal increases, the frame image of the moving image signal transmitted per unit time is increased. The transfer is performed after the number of lines and the number of line images constituting the frame image are reduced.

When the auto focus and auto iris functions described above are enabled, the operator changes the imaging direction of the electronic camera (pan, tilt), zooms, etc., and the frame image greatly changes. Even in cases other than the case where the focus and iris are sequentially changed in accordance with the movement of the subject, the information amount of the moving image signal after encoding increases, and as a result, for the above-described reason, the reproduction of the moving image signal There is a problem that the image quality and continuity of the obtained frame image are unnecessarily reduced.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a video conference apparatus in which the automatic correction of the imaging conditions of an electronic camera is appropriately restricted so as to suppress the deterioration of the image quality at the time of reproducing the resultant image signal. I do.

[0007]

In order to achieve the above object, according to the present invention, there is provided an electronic camera for generating image data according to an image pickup result and a correlation between frame images represented by the generated image data. An encoding circuit that converts the image data into encoded image data having a smaller data amount and outputs the encoded image data, and a circuit that thins out the image data so that the data amount of the encoded data is equal to or less than a predetermined data amount. A video conference device having an automatic correction circuit that automatically corrects an imaging condition of the electronic camera according to a movement of an imaging target, and detects a user operation on the electronic camera to change an image to be captured. And the correction performed by the automatic correction circuit is invalidated during a period excluding a period during which an operation is detected by the detection unit and a period of a predetermined length following the period. Comprising a control means for.

[0008]

According to the above-described means, the correction performed by the automatic correction circuit is performed except during the period when the user operates the electronic camera, that is, during the period when the image obtained by the imaging changes greatly between frame images. Is invalidated, so that a decrease in correlation between frame images represented by image signals generated by the electronic camera is suppressed. For this reason, the amount of image data lost by the means for thinning out image data is reduced, and as a result,
Deterioration in image quality of the frame image during reproduction is suppressed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 is a diagram showing a configuration of a video conference apparatus according to a first embodiment of the present invention.

Referring to FIG. 1, the apparatus includes a camera platform television camera 1 for outputting an image pickup result as a video signal, an A / D converter 2 for converting the video signal into digital data,
A frame memory 3 for storing digital data obtained by the conversion, a synchronization signal detection circuit 6 for extracting a synchronization signal from the video signal, a control circuit 7 for generating various control signals according to the extracted synchronization signal, Address generation circuits 4 and 8 for respectively generating a write address and a read address for the frame memory 3 according to the control signal.
And a switch 5 for outputting one of a write address and a read address to the frame memory 3 in accordance with a control signal, and a digital signal read from the frame memory 3 according to Recommendation H.264. 261, an encoding circuit 9 for performing high-efficiency encoding according to the method specified by H.261, an output circuit 10 for converting the encoding result into a signal of a predetermined format, and then outputting the signal to a communication line; 1, an operation panel 11 for individually outputting operation signals such as pan, tilt, zoom and the like in response to an operation command, and control of focus and iris according to an image on a monitoring area of a frame image represented by the video signal. An autofocus / iris circuit 12 for outputting a signal, and a camera control circuit 13 for supplying a control signal output from the autofocus / iris circuit 12 to the camera platform television camera 1 in response to the operation signal. This device differs from the conventional technology in that the above configuration has a camera control circuit 13.

Although not shown in the figure, the present apparatus includes a circuit for encoding an audio signal obtained at the time of imaging and multiplexing the encoded audio signal on the encoded moving image data, and a video conference apparatus of the other party. And a display for receiving video signals and reproducing video and audio from the received signals.

FIG. 2 is a diagram showing the configuration of the camera control circuit 13 described above.

The camera control circuit 13 shown in FIG.
A detection circuit 14 for detecting an operation signal from the counter 1 and a counter 15 for starting counting up according to the detection result
And a threshold circuit 18 for outputting a set threshold value
And a comparator 16 that compares the threshold value of the counter 15 with the threshold value of the threshold circuit 18, and supplies a control signal from the autofocus / iris circuit 12 to the camera platform television camera 1 according to the comparison result. And a switch 17.

Next, the operation of the present apparatus will be described.

The control circuit 7 shown in FIG. 1 controls the address generation circuit 4 and the switch 5 in response to the synchronization signal extracted by the synchronization signal detection circuit 8 when the video signal is captured, and generates the video signal by the address generation circuit 4. The write address to be written is supplied to the frame memory 3. The frame memory 3 sequentially stores the video signals converted into digital moving image data by the A / D converter 2 according to the supplied write address. When the control circuit 7 detects the boundary of the frame of the video signal from the vertical component of the synchronization signal, it switches the state of the switch 5 and controls the address generation circuit 8 to read the address generated by the address generation circuit 8. Is supplied to the frame memory 3. At the same time, the control circuit 7 activates the encoding circuit 9, and thereafter, the read address generated by the address generation circuit 8 is output according to the control of the encoding circuit 9. The frame memory 3 sequentially outputs the stored moving image data in accordance with the read address, and the output moving image data is encoded by the encoding circuit 9 and then transmitted to the destination via the output circuit 10 and the communication line. To the video conference device.
When the encoding of the moving image data for one frame is completed, the operation returns to the operation at the time of capturing the video signal, and the above operation is repeated.

The output circuit 10 controls the encoding circuit 9 according to the data amount of the encoded moving image data so that the encoded moving image data is transferred at a predetermined data rate. In addition, a process of thinning out a frame image represented by the moving image data and a line image constituting the frame image is performed. Also, as described above, encoded audio data is multiplexed with the encoded video data to be transmitted, and the other party's video conference device synchronizes the video and audio from the multiplexed signal with the multiplexed signal. Will be played. The same reproduction is also performed in the present apparatus, and a video conference is thereby performed.

On the other hand, in the camera control circuit 13 of FIG. 2, when the operation panel 11 is not operated by the operator, the switch 17 of the comparator 16 is in the OFF state. In this state, the auto focus / iris circuit 1
2. The focus and iris control signals output by
Since the image is not supplied to the camera platform TV camera 1, the focus and iris of the camera platform TV camera 1 are not corrected even when the subject of the camera platform camera 1 moves and the image on the monitoring area changes. When the operator operates the operation panel 11 to perform pan, tilt, and zoom, an operation signal indicating the operation is supplied to the camera platform television camera 1 and the camera control circuit 13. As a result, the pan head TV camera 1
Performs the movement (pan, tilt) and zoom according to the operation signal, and at the same time, the camera control circuit 13 performs the following operation.

First, the detection circuit 14 of the camera control circuit 13
While detecting at least one of the operation signals,
A reset signal is output to the counter 15, which clears the output count value to "0". When the comparator 16 detects that the count value of the counter 15 is smaller than the threshold value of the threshold circuit 18, the comparator 16 starts outputting a detection signal, and the switch 17 is turned on by the signal. As a result, the control signal from the autofocus / iris circuit 12 is supplied to the camera platform TV camera 1, and the focus and iris of the camera platform TV camera 1 are corrected according to the control signal. Then, when the operation signal is no longer detected due to the end of the operation of the operation panel 11, the detection circuit 14 stops outputting the reset signal, and thereafter, the counter 15 starts to operate at predetermined time intervals (update time intervals). Count value is '1'
It will be increased one by one. When the count value of the counter 15 increases and the count value becomes equal to or more than the output value of the threshold circuit 18, the comparator 16 stops the output of the detection signal and returns the switch 17 to the OFF state. Then, the counter 15 stops counting up. As described above, the switch 17 is turned ON only during a period in which the operation panel 11 is operated, and thereafter, during a period determined by the set value of the threshold circuit 18 and the update time interval of the counter 15. The set value of the threshold circuit 18 and the update time interval of the counter 15 are set so that the length of the period determined by them is longer than the time required for one autofocus or auto iris control. I have.

As described above, in this embodiment, the functions of the auto iris and the auto focus such as panning, tilting, and zooming are performed only when the operator intentionally operates the camera. Is effective, so that the entire frame image does not change frequently. As a result, the data amount of the encoded moving image data is reduced, and as a result, deterioration of the image quality and continuity of the frame image when the moving image data is reproduced is suppressed.

The encoding method used in the encoding circuit 9 is described in Recommendation H.264. International standard encoding methods other than H.261 may be used, a method that does not compress redundancy, or a non-standard encoding method may be used.

The operator manually operates the TV camera 1 directly.
A circuit and a mechanism for detecting the operation and the operation amount when the operation is performed may be provided in the television camera 1, and the detection result may be supplied to the camera control circuit 13 instead of the operation signal of the operation panel 11.

<Second Embodiment> Hereinafter, a video conference apparatus according to a second embodiment of the present invention will be described.

The present apparatus differs from the first embodiment only in the configuration of the part relating to the generation of the video signal.

FIG. 3 is a diagram showing a configuration of a part relating to generation of a video signal in the present apparatus. As shown in the figure, in the present apparatus, the operation signal of the operation panel 11 is supplied only to the camera platform television camera 1, and the camera control circuit 21
The supply of a control signal from the autofocus / iris circuit 12 to the camera platform television camera 1 is controlled in accordance with the control signal.

FIG. 4 is a diagram showing the configuration of the camera control circuit 21.

In the figure, a camera control circuit 21 compares a level of a control signal output from an auto-focus / iris circuit 12 with a threshold value output from a threshold value circuit 24, and outputs a comparison result. And a switch 22 for supplying the control signal to the camera platform television camera 1 accordingly. Note that the level of the control signal output from the autofocus / iris circuit 12 increases as the adjustment amount of focus and iris increases.

In the above configuration, the camera control circuit 21
Of the auto focus / iris circuit 12
When the level of the control signal is detected to be higher than the output value of the threshold circuit 24, the output of the detection signal is started,
The switch 22 is turned on by the signal. As a result, the control signal is supplied to the camera platform TV camera 1, and the focus and iris of the camera platform TV camera 1 are corrected. When the level of the control signal becomes equal to or less than the output value of the threshold circuit 24 due to the correction, the comparator 23 stops outputting the detection signal and returns the switch 22 to the OFF state. Thus, the correction of the focus and the iris is performed only during the period when the correction amount is larger than the threshold value of the threshold circuit 24. According to the above operation, the operator operates the operation panel 11 or manually directly.
When the camera platform camera 1 is operated, the focus and iris are also corrected.

As described above, in the present embodiment, the focus and the iris are not corrected following a slight defocus or a change in the amount of light unlike the related art. There is no change. As a result, similarly to the first embodiment, deterioration in image quality and continuity of a frame image when moving image data is reproduced can be suppressed.

<Third Embodiment> Next, a video conference apparatus according to a third embodiment of the present invention will be described.

The present apparatus has the following configuration except for the configuration of the television control circuit.
It has the same configuration as the device described in the first embodiment (FIG. 1). Further, the television control circuit of the present apparatus performs both the control performed by the television control circuit 13 (FIG. 2) of the first embodiment and the control performed by the television control circuit 21 (FIG. 4) of the second embodiment.
It is done at the same time.

FIG. 5 is a diagram showing a configuration of the television control circuit 31 provided in the present apparatus. In the figure, parts corresponding to those in FIGS. 2 and 4 are denoted by the same reference numerals.

In the configuration shown in the figure, an OR circuit 32 outputs a detection signal output from the comparator 16 in response to an operation signal of the operation panel 11 and a comparator 23 in response to a control signal from the autofocus / iris circuit 12. The output signal is logically ORed, and the signal indicating the result is used to turn on the switch 17 that is normally off. That is, in the present apparatus, the period during which the operator intentionally operates the camera, such as pan, tilt, and zoom, and the amount of focus and iris correction are greater than the threshold value of the threshold circuit 24. The focus and iris corrections are performed only during the period of increase.

As described above, according to the present embodiment, similarly to the first and second embodiments, it is possible to suppress the deterioration of the image quality and the continuity of the frame image at the time of reproducing the moving image data. Also, the present embodiment, when compared with the first embodiment,
Regardless of whether the camera is operated or not, there is an advantage that the automatic correction of the iris and the focus can be made effective when the image on the monitoring area is greatly changed. There is an advantage that the automatic correction can be enabled according to the operation speed.

Although the above embodiment relates to a video conference apparatus, the above configuration can be used as a video telephone as it is.

[0036]

According to the present invention, it is possible to provide a video conference apparatus in which the automatic correction of the imaging condition of the electronic camera is appropriately restricted so as to suppress the deterioration of the image quality at the time of reproducing the resultant image signal. Become.

[Brief description of the drawings]

FIG. 1 is a block diagram of a video conference device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a television control circuit 13 according to the first embodiment.

FIG. 3 is a block diagram of an image signal generation unit 40 'of the video conference device according to the second embodiment.

FIG. 4 is a block diagram of a television control circuit 21 according to a second embodiment.

FIG. 5 is a block diagram of a television control circuit 31 of the video conference device according to the third embodiment.

[Explanation of symbols]

1 ... head camera, 2 ... analog-to-digital converter,
DESCRIPTION OF SYMBOLS 3 ... Frame memory, 4 ... Address generation circuit, 5 ... Switch, 6 ... Synchronous signal detection circuit, 7 ... Control circuit, 8 ... Address generation circuit, 9 ... Encoding circuit, 10 ... Output circuit, 11
... operation panel, 12 auto focus / iris circuit, 13 camera control circuit, 14 detection circuit, 15 counter, 16 comparator, 17 switch, 18 threshold circuit, 21 camera control Circuit, 22 ... Switch, 23
... Comparator, 24 ... Threshold circuit, 31 ... Camera control circuit, 32 ... OR circuit, 40, 40 '... Image signal generator.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/232-5/243 H04N 7/15

Claims (3)

(57) [Claims] 1. An electronic camera for generating image data according to an imaging result, and the image data is converted into coded image data having a smaller data amount by utilizing a correlation between frame images represented by the generated image data. An encoding circuit for outputting, a means for thinning out the image data so that a data amount of the encoded data is equal to or less than a predetermined data amount, and an imaging condition of the electronic camera according to a motion of an imaging target. A video conferencing apparatus having an automatic correction circuit for automatically correcting the electronic camera, wherein the detection means changes an image to be captured, detects a user operation on the electronic camera, and the operation is detected by the detection means. Period and the period of the specified length following that period,
A video conference device comprising a control unit for invalidating the correction performed by the automatic correction circuit. 2. An electronic camera for generating image data according to an image pickup result, and the image data is converted into encoded image data having a smaller data amount by utilizing a correlation between frame images represented by the generated image data. An encoding circuit for outputting, a means for thinning out the image data so that a data amount of the encoded data is equal to or less than a predetermined data amount, and an imaging condition of the electronic camera according to a motion of an imaging target. A video conference apparatus having an automatic correction circuit for automatically correcting the correction performed by the automatic correction circuit during a period in which the amount of correction to be performed by the automatic correction circuit is smaller than a predetermined amount. A video conference apparatus, comprising: a control unit that sets a video conference. 3. An electronic camera for generating image data according to an imaging result, and the image data is converted into encoded image data having a smaller data amount by utilizing a correlation between frame images represented by the generated image data. An encoding circuit for outputting, a means for thinning out the image data so that a data amount of the encoded data is equal to or less than a predetermined data amount, and an imaging condition of the electronic camera according to a motion of an imaging target. A video conferencing apparatus having an automatic correction circuit for automatically correcting the electronic camera, wherein the detection means changes an image to be captured, detects a user operation on the electronic camera, and the operation is detected by the detection means. The automatic correction circuit does not include a period during which the automatic correction circuit performs a predetermined period following the period, and a period in which the amount of correction performed by the automatic correction unit is larger than the predetermined amount. Video conference system, characterized in that it comprises a control means for disabling the cormorants correction.