JP3031309B2 - Video conferencing 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 performing a video conference using a personal computer or a video conference terminal connected to a network, and more particularly to a video conference apparatus for effectively using a camera.

[0002]

2. Description of the Related Art A video conferencing apparatus has been put into practical use in which a plurality of persons use a network to conduct a conference while viewing images transmitted to each other, as in the case where a plurality of persons attend a conference room to conduct a conference. ing. Such a video conference device uses a personal computer or a video conference terminal connected to a telephone line, a network such as a LAN (local area network) or the like to talk while seeing each other's faces, or to use application software or Electronic whiteboards allow people to share their data. In addition, text data, graphics data,
Some devices have a function of exchanging various kinds of data such as audio data and image data in real time. A video input device such as a camera is connected to each terminal of these video conference devices, and participants of the video conference and materials used in the conference are photographed. The captured moving image data and other image data can be displayed on an image display device on the terminal side.

Japanese Patent Application Laid-Open No. 7-298232 discloses an example of such a video conference device. The video conference apparatus disclosed in this publication displays a moving image sent from a speaker without deteriorating the image quality, and also displays an image sent from another participant.

FIG. 9 is for explaining the video conference apparatus disclosed in this publication. This apparatus includes a CPU (Central Processing Unit) 101 for performing various controls. The CPU 101 includes an input device 102 for the user to operate the terminal, a memory 103 for storing programs and data for controlling the terminal, a display device 104 for displaying various information, Image / audio compression / expansion device 105 for compressing / expanding audio
And a multiplexing / demultiplexing device 106 for multiplexing various kinds of data such as images and voices at the time of transmission and separating these data at the time of reception, and a line control device 108 for controlling the line of the communication line 107. I have. The image / audio compression / expansion device 105 includes an image input device 109 such as a camera for inputting an image, an audio input device 111 such as a microphone for inputting audio, and an audio output device 112 for outputting audio. It is connected. The display device 10
4, an image memory 113 and a writing area switching means 114 for switching the writing area of an image for the image memory 113 are provided. In this device, the writing area switching means 114 is realized by software. Further, the CPU 101 of this apparatus realizes various operations of the video conference apparatus by executing a program stored in the memory 103.

FIG. 10 specifically shows a video / audio compression / decompression device and a demultiplexing device in the video conference device shown in FIG. An image decoder 121, an image encoder 122, and a switch 123 are arranged in the image / audio compression / expansion device 105. Image encoder 12
2 receives an image signal 124 to be transmitted obtained from the image input device 109, compresses and encodes the signal, and supplies it to the demultiplexing device 106 via the terminal S of the switch 123. . The demultiplexer 106 transmits the supplied image signal to the outside as shown in FIG.

[0006] The image encoder 121 is a demultiplexer 1
An image signal received from the outside obtained through the decoder 06 is decoded and decompressed, and the obtained moving image signal 125 is transmitted to the display device 104 shown in FIG. The switch 123 includes a terminal N in addition to the terminal S described above.
These are alternatively selected and the obtained image signal is supplied to the demultiplexer 106. Such switching control is performed by the CPU 101 shown in FIG. 9, and the terminal S is selected when the own terminal is the speaker, and the terminal N is selected when the other terminal is the speaker. You. That is, the switch 123 controls to return the image data input from the demultiplexer 106 as it is, in other words, to relay the image data and output the data from the demultiplexer 106 or to output the image data from the image encoder 122. Switching is performed so as to control the output data from the demultiplexer 106.

The video / audio compression / decompression device 105 and the demultiplexing device 106 actually include circuits relating to not only the image described above but also audio and other data. In the drawings, illustration and description are omitted.

FIG. 11 specifically shows the configuration of the display device shown in FIG. The display device 104 has an image memory 113 for writing and storing the received image.
Display means 131 for displaying an image; image memory 1
The display driver 132 includes a display driver 132 for inputting a received image read from the LCD 13 and generating a signal for display, and a writing area switching unit 114 also illustrated in FIG. The image memory 113 is divided into four writing areas A, B, C, and D as shown in FIG.
The writing area switching means 114 switches which of these areas to write. This switching control
It is performed by software, but is conceptually shown here using a switch.

In the example shown in FIG. 11, the image memory 113 is divided into four areas: an upper left writing area A, an upper right writing area B, an upper left writing area C, and a lower left writing area D. However, by changing the write address, other division numbers and division methods are of course possible. The writing area in which the moving image signal 125 obtained from the video / audio compression / expansion apparatus 105 is written can be changed by controlling the writing address by the CPU 101.

In this proposed video conference apparatus having such a configuration, the moving picture signal 125 shown in FIG. 10 is written frame by frame in the area specified by the writing area switching means 114 (FIG. 11) in the image memory 113. It has become. The image data written in the image memory 113 is converted into an appropriate signal for display by the display driver 132, and the display unit 131 performs display. The previous image is stored in an area of the image memory 113 where no writing is currently performed. Therefore, the writing area in which the received image is written is displayed as a moving image, while the other writing areas are displayed as still images.

FIG. 12 shows a control flow when a speaker is switched in the proposed video conference apparatus. The program for this control is shown in FIG.
Are stored in the memory 103 shown in FIG. The terminal is, for example, an ITU (International Telecommunications Union)
n) H. of the -T Recommendation. When receiving the LSD data indicated by H.221 (step S101), it is determined whether or not the speaker is the own terminal (step S102). Here, the LSD (Low Speed) data refers to a general-purpose data channel defined by a video conference system. If the speaker is the own terminal (Y), switch 1
23 (FIG. 10) is switched to the terminal S side (step S1).
03). As a result, moving images from the own terminal to other terminals,
That is, the moving image of the speaker is transmitted.

The transmitted moving image is relayed to another terminal, and then supplied to the image encoder 121 of the terminal via the demultiplexing device 106 of the terminal. However, when the speaker is the own terminal, the moving image is transmitted to the outside, and the moving image is transmitted to the demultiplexer 1
It is also possible to loop back the data at 06 and supply it to the image encoder 121 of this terminal.

If it is determined in step S102 that the speaker is not the own terminal (N), the switch 123 shown in FIG. 10 is switched to the terminal N side (step S10).
4). Thereby, the moving image of the speaker of another terminal as the received image becomes the transmission image as it is. That is,
The received image is relayed as it is and transmitted to an adjacent terminal.

After the control in step S103 or S104 is performed, the writing area switching means 114 (FIG. 11) is switched so that the image is written in the writing area corresponding to the speaker in the image memory 113. Will be As a result, the image of the speaker is displayed as a moving image, and the images of the other participants are displayed as still images on the display unit 131 of the terminal. Further, an image of a terminal that has not made a comment is also displayed as a still image.

FIG. 13 schematically shows the functional configuration of the proposed video conference apparatus. The video conferencing apparatus includes a reception image processing unit 141 for processing an image received from the outside, a transmission image processing unit 142 for processing an image signal 124 to be transmitted (see FIG. 10), and a plurality of video conferences participating in the video conference. Detecting means 143 for detecting which of the terminal devices is the speaker, transmission / reception switching processing means 144 for performing transmission / reception switching processing, and when the detection means 143 detects that its own video conference terminal is the speaker. A relay reception switching processing unit 145 for relaying an image signal received from the outside to the outside and supplying the received image signal to the reception image processing unit 141; and an image memory having a plurality of writing areas described with reference to FIGS. 113 and write control device 1
46. Here, the writing control device 1
Reference numeral 46 denotes a unit that controls the image signal 125 (FIG. 9) processed by the received image processing unit 141 to be written in the writing area of the image memory 113 in response to detection by the detection unit 143.

Detecting means 143 and write control device 146
Is realized by the CPU 101 shown in FIG. 9 and a program executed by the CPU 101. Further, the reception image processing means 141 is constituted by the image encoder 121 shown in FIG. The transmission image processing unit 142 includes the image encoder 122. The transmission / reception switching processing means 144 and the relay reception switching processing means 145 are constituted by the CPU 101, the demultiplexer 106 and the switch 123.

The operation of such a video conference device will be described. When the detection unit 143 detects that the speaker is the own terminal, the image signal processed by the transmission image processing unit 142 is transmitted to the other terminal through the transmission / reception switching processing unit 144. When the speaker is detected as another terminal, the received image signal from one adjacent terminal obtained through the relay reception switching processing means 145 is relayed as it is and transmitted to the other adjacent terminal, It is supplied to the reception image processing means 141.

The image signals 125 of the speakers of the own terminal and the other terminals processed by the received image processing means 141 are written into the image memory 113 by the writing control device 146.
By reading and displaying the contents of the image memory 113, an image of each conference participant is displayed on each of the plurality of divided areas on the display screen. At this time, the speaker who is currently speaking is displayed as a moving image, and the other participants are displayed as still images.

Japanese Patent Application Laid-Open No. 1-146487 discloses a technique in which image data information obtained from a camera is converted into a digital image, a part of the image is extracted when this image is encoded, and only this extracted portion is used. To be encoded,
A video conference apparatus having a switching unit for outputting a command for performing the encoding is disclosed. In the technology described in this publication, the focus of the video of the partner station is focused by the own station in a short time.

FIG. 14 shows the configuration of a video conference apparatus disclosed in Japanese Patent Application Laid-Open No. 1-146487. This apparatus includes a video codec 201A and a video codec 201 via a system control unit 202A.
A control unit 203A for controlling camera A
Controller 205A for controlling the image processing, an A / D converter 206A for converting an analog image captured by the camera 204A into a digital image, and a digital signal converted by the A / D converter 206A. And a coding unit 210A for coding a frame image stored in the transmission frame memory unit 207A and transmitting the frame image to the multiplexing unit 209A of the transmission control unit 208A. The line 211
, The code "A" after the numeral is replaced with the code "B" to represent and fold, and a detailed description thereof will be omitted.

The multiplexing unit 209A multiplexes the image data input from the encoding unit 210A and, for example, the focusing information of the other station camera 204B based on an operation command from the system control unit 202A. And this is line 2
11 to the video codec 201B of the partner station.

The separating section 212B receives the multiplexed information and separates the multiplexed information into image data information and information such as focusing information of the camera 204B. Separation unit 212
The focusing information of the camera 204B extracted in B is sent to the system control unit 202B. An image that changes according to the amount of movement of the camera 204B via the camera controller 205B is transmitted from the partner station via the A / D converter 206B, the transmission frame memory 207B, the encoder 210B, and the transmission controller 208B each time. It is configured to be transmitted to the separation section 212A of its own station.

The decoding section 213A restores the coded image information obtained from the separation section 212A to the original state. The reception frame memory unit 214A is for storing the decoded image data information.
Further, the D / A converter 215A converts the decoded digital image into an analog image and converts the digital image into an analog image.
This is for performing the conversion for projecting the image on the screen. The television monitor 216A displays an image when the remote station camera 204B is remotely operated by the operation unit 203A, and the system control unit 202B of the remote station transmits the image based on a focus command by the operation unit 203A of the local station. , The mode switching command 221A,
A and to the encoding unit 210A.

The operation of the video conference apparatus described in this publication will be described. The mode switching command 221A is a command signal for switching from the standard mode for encoding the entire screen to the focus mode for encoding only an image in this area using a part of the screen as a fixed area. The ratio of the fixed area to the entire screen can be determined to be 1 / N where N is an integer. The system control unit 202B sends a mode switching command 221B to the transmission frame memory unit 207B and the encoding unit 210B. That is, a command signal for switching from the standard mode for encoding the entire screen to the focus mode for encoding 1 / N of one screen is transmitted. Therefore, by switching to the focus mode, the information generated by the encoding unit 210B becomes approximately 1 / N, and the motion of the video displayed on the monitor TV 216A of the own station is faster than that of the standard mode. And focusing can be performed smoothly.

[0025]

SUMMARY OF THE INVENTION The prior art 2 described above
In the video conferencing apparatus, the former technique divides an image memory into several areas and allocates the divided areas to moving image data input from an image input device and images received from other terminals connected in a loop. Like that. Even if a plurality of image memories for storing moving image data input to the own terminal are assigned, only one image memory is provided for display and moving image data transmitted to another terminal. . Therefore, the camera cannot be used for other purposes.

In the former technique, input image data and received image data sent from another terminal are switched by a switch and written in an image memory. For this reason, all the moving image data input from the camera is transmitted to the connection destination of the video conference, and the camera cannot be used for other purposes from this point. In the latter technique, a command signal for focusing the camera is transmitted to another terminal, but the transmission control of the image data itself is not performed.

It is therefore an object of the present invention to provide a video conference apparatus which can use the camera for other purposes even when the camera is used in the video conference.

Further, in the conventional video conference apparatus, when a plurality of conference participants attend the same conference participation place and try to switch their moving images with one video camera, the switching is in progress. In some cases, an image that is not necessarily suitable for transmission is transmitted to another conference terminal.

Another object of the present invention is to provide a video conferencing apparatus which can switch a moving image naturally when a single video camera switches moving images of a plurality of conference participants at the same conference participating place. To provide.

[0030]

According to the first aspect of the present invention, there are provided (a) a video camera, (b) a video buffer for storing image data input from the video camera, and (c) the video buffer. Image compression means for compressing the image data read from the video camera; (d) video camera use switching means for switching the video camera between video conferencing and other uses; and (e) video camera use switching. While the means is switching the video camera from video conferencing to other uses, a capture area is secured in the video buffer by interrupting and securing a capture area for newly storing image data for uses other than this video conference. Means, and (h) when the capture area securing means interrupts an area in the video buffer and uses the area in the video buffer, The image data is compressed for video conferencing using the area of the video conferencing and sent out to the communication line connected to the other party of the video conferencing. Otherwise, the originally required memory in the video buffer for transmitting moving images The video conference apparatus is provided with video conference image data transmitting means for compressing image data using the entire area and transmitting the compressed data to a communication line.

That is, according to the first aspect of the present invention, the capture area is interrupted in order to newly store image data for a purpose other than the video conference in a video buffer originally used for the video conference. I decided to secure it and compressed and stored the image data for video conferencing to cover the area reduced by this interrupt,
This is transmitted to a communication line connected to the other party of the video conference.

According to the second aspect of the present invention, the capture area securing means in the video conference apparatus according to the first aspect is arranged such that when the video camera use switching means sets the video camera for the video conference, the entire area of the video buffer is set to the video. It is characterized in that it is used for a conference, and while the video camera is switched to a use other than the video conference use, an area required for the use is interrupted as a capture area.
As a result, the capture area can be secured with the existing video buffer.

According to the third aspect of the present invention, when the video camera application switching means in the video conference apparatus of the first aspect sets the video camera to a use other than the video conference, the image compression means sets the resolution to the video conference. In this case, the image data is compressed by increasing the period of the image frame in accordance with the ratio of the capture area. By increasing the cycle of the image frame in this manner, the image data can be used for a conference without reducing the resolution.

According to the fourth aspect of the present invention, (a) a video camera, and (b) subject switching means for switching a moving image of a plurality of conference participants who have attended the same conference participant with the video camera, A video buffer for continuously storing image data of a moving image input from the video camera over a plurality of frames; (d) image compression means for compressing image data read from the video buffer; A) moving image cut means for cutting the transmission of the moving image being switched to the video conference participant as the video camera switching means switches the image of the subject;
(F) The time at which the transmission of the moving image is cut by the moving image cutting means is determined by the moving image for a plurality of frames before the cut moving image stored in the video buffer by the frame of the image by the image compressing means. The video conferencing apparatus is provided with an image compression means and a frame cycle control means to make up.

That is, the invention according to claim 4 deals with a case in which moving images of a plurality of conference participants who have attended the same conference participating place are switched by a video camera, and the images being switched are cut. For example, in the case where two images are switched while the images are being played by a camera, there may be an unsightly image in which the images of these two people are hardly displayed. In such a case, while the transmission of the image of the portion is cut, the moving images of a plurality of frames before the cut moving image stored in the video buffer are filled with the image frame by the image compressing means. I have to.

According to a fifth aspect of the present invention, the moving image cutting means according to the fourth aspect is characterized in that the moving image cut means immediately before the part of the image of the new conference participant appears in the moving image frame. The time covering the time until all the participants' images are no longer photographed is set as the minimum time, and the moving image is cut. Further, in the invention according to claim 6, the image for compensating for the time during which the transmission of the moving image is cut is made equal to the resolution of the other images and the frame period is lengthened, and the quality of the compensated image is maintained. ing.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

FIG. 1 shows the configuration of a video conference apparatus according to an embodiment of the present invention. This device comprises a video conference device main body 311, an audio input device 312, an image input device 313, and a data input device 314 as input devices connected thereto, and an audio output device 315 and a display device 316 as output devices. Has been
It is connected via a communication line 317 to a video conference device (not shown) as a conference partner.

Here, the video conference apparatus main body 311 stores moving image data, image data, audio data, text data,
This is a circuit device for mutually inputting and outputting various data such as graphics data with another video conference device (not shown) for a conference. The voice input device 312 is typified by a microphone, and is for inputting voice. The audio output device 315 is typified by a speaker or a headphone and outputs audio. The image input device 313 is typified by a camera, and inputs an image. On the other hand, the data input device 314 is represented by a pointing device such as a mouse or a tracking ball or a keyboard, and is used to input various data for operating the video conference device. The display device 316 displays the image data input from the image input device 313 and the communication line 3.
17 for displaying image data such as image data obtained by decoding the compressed image data received by the CPU 17 or image data transmitted to a video conference device (not shown) at a connection destination. It is constituted by.

The video conference apparatus main body 311 includes a voice control unit 321 connected to a voice input device 312 and a voice output device 315. The audio control unit 321 controls input and output of audio data, and is connected to the audio data processing unit 322. Voice data processing means 322
Is also connected to the demultiplexing means 323, and compresses audio data input via the audio control means 321;
The decoding of the compressed audio data received from the demultiplexing means 323 is performed.

The demultiplexing means 323 is connected to the line control means 3
25 and a display control unit 327 via an image data processing unit 326. Here, the display control unit 327 is connected to the image input device 313 and the display device 316, and performs display control when the image data input from these devices is visually displayed on the display device 316. ing.
The image data processing means 326 performs processing such as encoding and decoding of image data. The demultiplexing means 323 includes
When transmitting the compressed audio data and image data to the communication line 317, the process of multiplexing the data into a predetermined data format and the process of separating the data received from the line control unit 325 into audio data and image data are performed. The line control unit 325 controls transmission and reception of data via the communication line 317. Video conference device main body 311
Is also provided with a main control means 328. The main control unit 328 is connected to each unit such as the data input device 314 and performs various controls as a video conference device.

FIG. 2 shows a specific configuration of the image data processing means. Image data processing means 326
Means image data switching means 3 for switching image data
31 are provided. The image data switching means 331 is configured as shown in FIG.
The image data 333 input from the display control means 327 (FIG. 1) is stored in one of the first and second image buffers 334 and 335 in accordance with the camera switching signal 332 supplied from the main control means 328 shown in FIG. It is supposed to. These image buffers 334, 335
Is constituted by a memory area for storing a plurality of frames of the input image data. The image data selection means 336 outputs image data 337, 33 output from the first or second image buffer 334, 335 according to the camera switching signal 332 supplied from the main control means 328.
8 is selected and supplied to the image encoding unit 341 as image data 339. Image encoding means 34
1 encodes the image data 339 input from the image data selection means 336 and supplies it as image data 342 to the demultiplexing means 323 shown in FIG.

FIG. 3 shows a flow of processing of image data input by the camera in the video conference apparatus of the present embodiment. The image data input from the image input device 313 shown in FIG. 1 to the video conference device main body 311 is transmitted to the image data 333 via the display control unit 327.
(FIG. 2) is input to the image data processing means 326. The image data switching means 331 in the image data processing means 326 determines whether the destination to store the image data 333 is the first image buffer 334 according to the camera switching signal (image memory flag) 332 supplied from the main control means 328. It is determined whether or not the image buffer is the second image buffer 335 (step S201). When the instruction of the image memory flag indicates the first image buffer 334 (Y),
The image data 333 is stored therein (step S20).
2). On the other hand, when the instruction of the image memory flag does not indicate the first image buffer 334 (N), the image data 333 is stored in the second image buffer 335 (step S203).

When the image data 333 is stored in the first or second image buffer 334 or 335 as the discrimination destination in this manner, a camera switching instruction is issued to the data input device 31.
4 (steps S204 and S204).
205). This instruction is input by the user using a key input device. Such an input instruction is performed when the user wants to use the camera for a purpose other than the video conference while using the camera for the video conference. As an example of the instruction method, a button for selection is displayed on the screen of the display device 316, and any of these buttons is selected with a mouse or a cursor key, or a button dedicated to the image input device 313 such as a camera. It is conceivable to arrange a switching button.

When a camera switching instruction is issued (step S
204, S205; Y), the image data switching means 331 shown in FIG.
The process of storing the image data in 335 is stopped (step S206). The timing of stopping is frame unit as a processing unit of the input image data 333. Next, the image memory flag is set so as to indicate the image buffer of the first and second image buffers 334 and 335 other than the one currently storing the image data (step S207). Thereafter, returning to step S201,
It is determined whether the image data 333 of the next frame is stored in the first image buffer 334 or the second image buffer 335. The same applies to the following, and the image data is stored in the first or second image buffer 334 or 335 of the determination destination in frame units.

FIG. 4 shows a flow of an encoding process of image data input from an image input device such as a camera. The image data selection means 336 in the image data processing means 326 shown in FIG. 2 determines whether the camera switching signal (image memory flag) 332 supplied from the main control means 328 indicates the first image buffer 334. A determination is made (step S301). First image buffer 3
If the instruction has been given (Y), the image data 337 is read out (step S302). On the other hand, if the first image buffer 334 has not been designated (step S301; N), that is, if the second image buffer 335 has been designated, the second image buffer 335 The image data 338 is read (step S303).

The above step S302 or step S
When the processing of step 303 is performed, unless there is a camera switching instruction (steps S304 and S305; N), the image encoding unit 341 encodes the image data 339 selected by the image data selecting unit 336. (Steps S306 and S307). When the user has issued a camera switching instruction (steps S304, S30
5; Y), the image data 3
An instruction is given to perform the encoding of 39 with processing priority (steps S308 and S309). The instruction for performing the encoding with the processing priority is given by the main control unit 328 having a flag indicating the instruction state, and performs a toggle operation as an operation of alternately switching according to the state of the flag. If there is no camera switching instruction, no instruction to perform such encoding with processing priority is given.

When an instruction is given to the image encoding means 341 to perform the encoding with priority on the processing, the encoding for increasing the time required for the encoding is performed by the first accessing the processing.
Alternatively, the processing is performed until the image data in the second image buffers 334 and 335 runs out (steps S310 and S311).
Corresponding first or second image buffer 334, 335
When there is no more image data, the main control unit 328 supplies a camera switching instruction to the image data switching unit 331 (step S312). Thereby, the image data 33
3 will be switched.

FIG. 5 shows the processing of image data in accordance with the camera switching in this embodiment in units of frames. FIG. 7A shows image data 333 (see FIG. 2) inputted from the display control means 327 shown in FIG. 1 to the image data processing means 326 in units of frames. In this figure, the arrow t indicates the direction in which time passes. Also, in this figure, each frame is given a number “1”, “2”,. Further, the hatched frame (fifth frame) in FIG. A indicates that this is the first frame after the camera switching is instructed.

FIG. B shows the image data 333 stored in the first image buffer 334, and FIG. C shows the image data 333 stored in the second image buffer 335. It can be seen that the storage location of the image data 333 has been switched from the second image buffer 335 to the first image buffer 334 when the camera switching instruction is issued. FIG. 9D shows image data 342 encoded by the image encoding means 341 shown in FIG. Similarly, B to D in FIG. 5 show image data in frame units, and the numbers “1”, “2”,...

The operation of the video conference apparatus will be described with reference to FIG. Assume that the user issues a camera switching instruction 351 at a timing indicated by a dotted line between the fourth frame and the fifth frame as shown in FIG. Until this instruction is issued, the image data 33 shown in FIG. 2 is stored in the first image buffer 334 as shown in FIG. 5C. These first to first
The image data of the fourth frame is still image encoding means 341
, And remains stored in the first image buffer 334.

When the camera switching instruction (351) is issued and a camera switching signal (image memory flag) 332 is generated, the image data input from the image input device 313 is switched by the image data switching means 331 to the second image. The storage in the buffer 335 is started. FIG. 5B shows this image data after the camera switching signal 332 has been generated.

The image data selecting means 336 keeps the first image buffer 3 until the camera switching signal 332 is generated.
The image data 337 read out from the image data 33
9 and input to the image encoding means 341 to perform encoding. FIG. 5D shows this state. Since the processing time required for encoding the image is longer than the speed at which the image data 339 is input, in the period a corresponding to the stage temporally before the camera switching instruction 351, the previous frame (− (minus)) For example, “frame drop” occurs at a rate of one frame for every two frames.

The camera switching signal 332 is transmitted to the image encoding unit 3
When it is input to 41, it switches to the encoding process with a higher priority. As a result, at the expense of processing speed, encoding of each frame is sequentially performed so as to prevent frame dropout (FIG. 5D). In this manner, when the encoding processing for the four frames (first to fourth frames) stored in the first image buffer 334 is completed, the image encoding unit 341 sends the image data switching unit 331 Instructs camera switching. As a result, the image data switching unit 331 switches the storage destination of the image data 333 to be input thereafter to the first image buffer 334 again. The image encoding unit 341 encodes the image data 337 stored in the first image buffer 334 from the input image data 333 of the 16th frame (period b).

FIG. 6 shows the processing of image data on a frame basis when an instruction to switch cameras is issued before the reading of image data from the first image buffer is completed. The same parts as those in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

If the user gives the next camera switching instruction 352 before all the image data in the first image buffer 334 is encoded, the image data switching means 331 changes the storage location of the input image data 333. Switch to the first image buffer 334. Also, the image encoding means 341
Switches the encoding method to speed priority. As a result, the encoding of the image data as shown as the period c is performed.

As described above, the image data stored in the second image buffer 335 shown in FIGS. 5B and 6B is not encoded. As a result, the user can freely process the image data stored in the second image buffer 335, and can use the camera for another purpose even when the camera is being used in a video conference. Becomes possible.

Modification

In the embodiment described above, the case where the camera is used for photographing a participant of a video conference and for other purposes (video capture) is described. In such a case, there is a case where one camera switches and shoots a participant of the video conference. In such a case, the present invention is also applicable to a case where the camera replaces an image at the time of switching shooting, for example, from one participant to another participant, with the previous image to make the switching natural. Can be applied.

FIG. 7 shows two cameras arranged at the same point.
This is a state in which a human subject is switched. The first participant 401 of the video conference is photographed as a subject during times t ₁ , t ₂ , and t ₃ that elapse at equal intervals, and at time t ₄ , the second participant 4 as the next subject is photographed.
02 is photographed together with the first participant 401 as an image for one frame. The next time t ₅ or later is only the second of the participant 402 is photographed. To remove the time t ₄ of the frame of this, the frame period longer without reducing the resolution images of each previous frame.

FIG. 8 shows a series of images output to another video conference terminal in this way. Thus, by replacing the image at the time of camera switching with the immediately preceding image, for example, it is possible to smoothly switch the images of the speakers. In the above-described embodiment, two types of memories, a first image buffer and a second image buffer, are prepared in advance as memories for storing image data.
When one image buffer is prepared and two types of the first image buffer and the second image buffer are used in the embodiment, this one image buffer is divided into two types of image buffers. Should be used. At this time, since the capacity of the buffer memory for storing the moving image is reduced, when reading out the image without lowering the resolution, it is necessary to take measures to lengthen the frame cycle accordingly.

[0063]

As described above, according to the first aspect of the present invention, when a video buffer originally provided for use in a video conference is used for other purposes, image data for the video conference is used. I decided to compress and store
The video buffer of the existing video conference device can be used as it is, and an economical video conference device can be configured.

According to the second aspect of the present invention, in the video conferencing apparatus according to the first aspect, the capture area securing means sets the entire area of the video buffer when the video camera use switching means sets the video camera for the video conference. For video conferencing, while switching this video camera to a purpose other than video conferencing, we decided to interrupt the area required for this purpose as a capture area,
For normal use, there is an advantage that a moving image can be stored with a sufficient memory area secured.

According to the third aspect of the present invention, when the video camera application switching means in the video conference apparatus of the first aspect sets the video camera to an application other than the video conference, the image compression means sets the resolution to the video conference. The feature is that image data is compressed by extending the frame cycle of the image according to the proportion of the capture area, so that the image data can be used for meetings without reducing the resolution. Therefore, images can be transmitted with sufficient quality when presenting materials and the like.

According to the fourth aspect of the present invention, when moving images of a plurality of conference participants who have attended the same conference participation place are switched by one video camera, not only the transitional images are deleted, but also Since the image of the participant immediately before is inserted into the section as a moving image, the image of the participant can be switched more naturally than when a still image is inserted.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a specific configuration of the image data processing means shown in FIG.

FIG. 3 is a flowchart showing a flow of processing of image data input by a camera in the video conference apparatus of the embodiment.

FIG. 4 is a flowchart illustrating a flow of an encoding process of image data input from an image input device such as a camera.

FIG. 5 is an explanatory diagram showing a state of processing of image data according to the camera switching in the embodiment in units of frames.

FIG. 6 is a flowchart illustrating a state of processing of image data in units of frames when a camera switching instruction is issued before reading of image data from a first image buffer is completed.

FIG. 7 is an explanatory diagram showing how a camera switches a subject in a modification of the present invention.

FIG. 8 is an explanatory diagram showing a flow of an image transmitted by a video conference terminal according to a modified example of the present invention.

FIG. 9 is a block diagram showing an outline of a configuration of a conventionally proposed first video conference device.

FIG. 10 is a block diagram specifically showing a video / audio compression / decompression device and a demultiplexing device in the video conference device shown in FIG. 9;

11 is a block diagram specifically showing a configuration of the display device shown in FIG.

12 is a flowchart showing a state of control at the time of switching of speakers in the video conference apparatus shown in FIG. 9;

FIG. 13 is a block diagram schematically illustrating a functional configuration of the bio-conference device illustrated in FIG. 9;

FIG. 14 is a block diagram showing a configuration of a conventionally proposed first video conference device.

[Explanation of symbols]

 101 CPU (Central Processing Unit) 102 Input Device 103 Memory 104 Display Device 105 Image / Audio Compression / Expansion Device 107 Communication Line 109 Image Input Device 113 Image Memory 114 Writing Area Switching Means 123 Switch 131 Display Means

Claims (6)

(57) [Claims] A video camera; a video buffer for storing image data input from the video camera; an image compression means for compressing image data read from the video buffer; A video camera application switching means for switching to any of the conference use and the other use; and a video camera use change means for switching the video camera from the video conference use to the other use in the video buffer. A capture area securing means for interrupting and securing a capture area for newly storing image data for use other than video conference; and a video when the capture area securing means interrupts and uses an area in the video buffer. The remaining space in the buffer is used to compress video data for video conferencing. Sent to the communication line connected to the other party of the conference,
In other cases, there is provided a video conference image data transmitting means for compressing image data using the entire memory area originally required in the video buffer for transmitting a moving image and transmitting the compressed image data to the communication line. A video conferencing device characterized in that: 2. The video camera according to claim 2, wherein said capture area securing means sets said video camera for video conferencing when said video camera use switching means sets said video camera for video conferencing. 2. The video conference apparatus according to claim 1, wherein an area required for this use is interrupted as a capture area while switching to another use. 3. When the video camera use switching means sets the video camera for use other than video conferencing, the image compression means sets the resolution to the same as that for video conferencing, and sets the frame cycle of the image. 3. The video conference apparatus according to claim 2, wherein the image data is compressed by increasing the length according to the ratio of the capture area. 4. A video camera, subject switching means for switching a moving image of a plurality of conference participants who have attended the same conference participant with the video camera, and a plurality of image data of the moving image input from the video camera. A video buffer that continuously stores frames, an image compression unit that compresses image data read from the video buffer, and a video buffer that is being switched as the video camera switching unit switches the image of the subject. A moving image cutting means for cutting the transmission of the moving image to the video conference participant; and a time when the transmission of the moving image is cut by the moving image cutting means is stored in the video buffer. Image compressing means for compensating a plurality of frames of moving images in front of the image with image frames by the image compressing means Video conferencing apparatus characterized by comprising a cycle control device. 5. The moving picture cutting means stops the whole participant's image taken immediately before a part of a new participant's image appears in a moving image frame from being captured. The moving image is cut with the time covering up to the time point as a minimum time.
The video conference device according to 4. 6. The video conferencing apparatus according to claim 4, wherein the image for compensating for the time during which the transmission of the moving image is cut has a longer frame period with the same resolution as the other images. .