JPH07131773A - Picture communication terminal equipment - Google Patents

Abstract

PURPOSE:To simply realize an automatic answering function of still picture message data by adding a picture storage memory to store a still picture message and a simple control circuit to a picture communication terminal equipment not having an automatic message recording function. CONSTITUTION:When a mode changeover section 17 switches the mode from a usual communication mode into an automatic message recording mode, a control section 20 receives a switching signal from the changeover section 17 to detect the changeover of the mode. Then a succeeding frame to that of a video input signal from a camera 1 is discriminated to be still picture message data of a still picture to a destination terminal equipment, a pre-processing section 2 processes an object frame and writes it to a frame memory 3. The control section 20 sends a still picture mode setting control signal to an encoder section 4 and applies encoder processing to a video transmission signal in the memory 3 and stores a multiplexed video signal to be processed to a memory 5. When a call comes from a destination terminal equipment to the concerned terminal equipment in this state, the concerned terminal equipment is replied automatically and a multi-value processing video signal stored in a transmission memory 5 as still picture message data to realize the automatic message recording.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video conference for processing according to a moving image compression algorithm, enabling image data communication with a partner terminal, communicating and storing still image message data, and realizing an answering machine function. / It relates to an image communication terminal such as a telephone terminal.

[0002]

2. Description of the Related Art In recent years, the market expansion of image communication terminals such as video conferences / telephone terminals is expected due to the spread of ISDN and the recommendation of image encoding algorithms in CCITT. Such an image communication terminal is required to have an answering machine function for image message data as well as an answering machine function for voice possessed by a telephone or the like which performs voice communication. It is also required to be small and inexpensive.

Next, a conventional example will be described with reference to FIG. Figure 6
1 is a block diagram of a conventional example, 1 is a camera for inputting an image on its own side, 2 is a pre-processing unit for inputting an analog video signal, and outputting a digital video transmission signal in a common intermediate format, 3 is a digital video A transmission frame memory for temporarily holding a transmission signal, 4 an encoder unit for reading and encoding a digital video transmission signal from the transmission frame memory 3, and 5 a holding unit for a multiplexed video signal output from the encoder unit 4. A transmission buffer memory 6 for reading the multiplexed video signal from the transmission buffer memory 5 and multiplexing various signals such as the multiplexed video signal, voice data, data, and system control signal, and multiplexing from the other terminal. A demultiplexing / demultiplexing unit that demultiplexes the demultiplexed received signal (for example, performs processing according to CCITT H.221 recommendation), A network 7 receives the multiplexed transmission signal output from the multiplexing / demultiplexing unit 6 and outputs the transmission data to the communication network, and also receives the reception data from the communication network and outputs the multiplexed reception signal to the multiplexing / demultiplexing unit 6. An interface unit, 8 is a receiving buffer memory for temporarily holding the separated video signal output from the multiplexing / demultiplexing unit 6, and 9 is a decoder unit for reading and decoding the separated video signal from the receiving buffer memory 8. Is a reception frame memory for temporarily holding the common intermediate formatted digital video reception signal output from the decoder unit 9, and 11 is a reverse common intermediate formatted analog for reading the digital video reception signal from the reception frame memory 10. A post-processing unit for outputting a video output signal, 12 is a monitor for inputting and displaying an analog video output signal, and 13 is Record the image message data sent to the other party's terminal when the other terminal is in answering machine mode, and play back the image message data recorded in advance on the other party's terminal when the other party's terminal is in answering machine VTR for transmission message that outputs analog video signal for transmission message, 1
Reference numeral 4 denotes a transmission video controlled so as to connect the analog video signal from the camera 1 to the preprocessing unit 2 in the normal communication mode, and the transmission message analog video signal from the transmission message VTR 13 to the preprocessing unit 2 in the answering machine mode. A signal switching unit, 15 is a VTR for a reception message for recording an analog video output signal which is a reception message from the other party in the answering machine, and 16 is an analog video output signal from the post-processing unit 11 in the normal communication mode. In the answering machine mode again, the post-processing unit 11
Receives analog video output signal from VT for message
A receiving video signal switching unit controlled to connect to R15, 17 is a mode switching unit for switching the own terminal to a normal communication mode or an answering mode, and 18 is a VTR for a transmission message in response to a switching signal from the mode switching unit 17.
13, a transmission video signal switching unit 14, a reception message VTR 15, and a reception video signal switching unit 16.

The operation of the conventional image communication terminal configured as described above will be described below. In the normal communication mode, the analog video input signal which is the image on the local side input from the camera 1 is the transmission video signal switching unit 14
Is connected to the preprocessing unit 2 under the control of. The preprocessor 2 converts the analog video input signal into a common intermediate format, outputs a digital video transmission signal, and holds it in the transmission frame memory 3. The encoder unit 4 reads the digital video transmission signal from the transmission frame memory 3 and outputs a moving image compression algorithm (for example, CCITT H.264).
The low-speed moving image compression algorithm compliant with the H.261 recommendation) is coded and the coded image signal is multiplexed and the multiplexed video signal is written in the transmission buffer memory 5. The multiplexed video signal held in the transmission buffer memory 5 is multiplexed by the multiplexer / demultiplexer 6 with various signals such as other audio signals, data and system control signals, and the multiplexed transmission signal is output. This multiplexed transmission signal is transmitted to the partner terminal via the network interface unit 7. Further, the reception data sent from the partner terminal is received by the network interface unit 7 and the multiplexed reception signal is output to the multiplexing / demultiplexing unit 6. The demultiplexing / demultiplexing unit 6 demultiplexes only the image component from the data of the multiplexed reception signal and retains the demultiplexed video signal in the reception buffer memory 8. The decoder unit 9 reads the separated video signal from the reception buffer memory 8 and outputs the digital video reception signal which has been subjected to common intermediate formatting according to a moving image compression algorithm (for example, a low-speed moving image compression algorithm compliant with CCITTH.261 recommendation). It is output and written in the receiving frame memory 10. Post-processing unit 1
In 1, the common intermediate format digital video reception signal is read from the reception frame memory 10 and converted into an analog video output signal (composite video signal or the like), and the reception video signal switching unit 16 is connected to the monitor 12 and connected to the analog video. The output signal is output to the monitor 12 and the image of the other party is displayed.

In the answering machine, the transmission video signal switching unit 14 is connected to the transmission message VTR 13 side, reproduces the image message to the other side recorded in the transmission message VTR 13 in advance, and outputs it to the preprocessing unit 2. It The subsequent processing is the same as in the normal communication mode. The image message sent from the other party is processed in the same manner as in the normal communication mode and sent to the post-processing unit 11. The reception video signal switching unit 16 is connected to the reception message VTR 15, and the analog video output signal from the post-processing unit 11 is recorded by the reception message VTR 15. Thus, the answering machine function for the image signal in the image communication terminal is realized.

[0006]

However, in the above-mentioned conventional configuration, since the VTR for the transmission message and the VTR for the reception message are required, there is a problem that the terminal becomes large and very expensive. Had.

Therefore, the present invention provides a VTR for outgoing messages.
It is an object of the present invention to provide a small and inexpensive image communication terminal by eliminating the need for a VTR for receiving messages and received messages.

[0008]

To this end, the image communication terminal of the present invention receives the analog video input signal from its own camera and outputs the digital video transmission signal converted into a common intermediate format. A processing unit, a transmission frame memory that temporarily holds an input digital video transmission signal, and a digital video transmission signal that is read from the transmission frame memory and encoded according to a moving image compression algorithm. Encoding unit for multiplexing, transmission buffer memory for temporarily holding the multiplexed video signal multiplexed by the encoding unit, read multiplexed video signal from the transmission buffer memory, audio, multiplexed video signal, data, system Multiplexing that multiplexes various signals such as control signals, and multiplexes received signals from the other terminal A demultiplexing unit, a network interface unit that inputs a multiplexed multiplexed transmission signal, outputs a transmission signal to a communication network, and outputs a counterpart reception signal that is input from the communication network to a demultiplexing / demultiplexing unit, and a demultiplexing / demultiplexing unit A receiving buffer memory that temporarily holds the separated video signal output from the receiving unit, a decoder unit that separates the decompressing video signal from the receiving buffer memory according to a moving image compression algorithm, expands it, and converts it into a common intermediate format; A receiving frame memory that holds a common intermediate-formatted digital video reception signal output from the unit, a post-processing unit that reads the digital video reception signal from the reception frame memory and outputs an analog video output signal to the monitor,
A mode switching unit that switches between the normal communication mode and the answering machine mode of the own terminal, and a first control unit that controls the mode switching of each block by the control of the mode switching unit,
Only the frame of the local analog video input signal input from the local camera when the mode is switched from the normal communication mode to the answering machine is processed as still image message data to the remote terminal and is stored in the transmission buffer memory. In this case, the still image message data held in the transmission buffer memory is transmitted to the partner terminal when there is an incoming call from the partner terminal in the answering machine. In addition, an image storage memory that stores the received digital video signals output from the decoder unit is provided, and when the local terminal holds the still image message data from the other party in the answering machine mode and plays it back when the answering machine mode is released, it stores the image. The memory stores the predetermined frame data transmitted from the other side.

[0009]

The present invention has the above-mentioned configuration and is for V
It is possible to realize an answering machine function by sending and storing still image message data by simply adding an image storage memory to an image communication terminal that does not have an answering machine function, without the need for TR and VTR for receiving messages. It is inexpensive and can be reduced in size. Further, by instructing the timing of taking in the still image message data, the image message can be stored at the optimum timing. Further, the amount of still image message data can be further compressed and stored again by using the preprocessing function and the encoding function on its own side, thereby enabling efficient use of the image storage memory.

[0010]

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

FIG. 1 is a block diagram of the image communication terminal of the first embodiment. In the first embodiment, the moving image compression algorithm of the encoder unit is CCITT H.264. In the low-speed moving image compression algorithm recommended by H.261, the multiplexing / separation of the multiplexing / separating unit is CCITT H.264. 221, which will be described below.

Reference numeral 1 is a camera, 2 is a preprocessing unit, 3 is a transmission frame memory, 4 is an encoder unit, 5 is a transmission buffer memory, 6 is a multiplexing / demultiplexing unit, 7 is a network interface unit,
8 is a receiving buffer memory, 9 is a decoder unit, 10 is a receiving frame memory, 11 is a post-processing unit, 12 is a monitor,
Reference numeral 17 denotes a mode switching unit, which is similar to the conventional example, and therefore, is given the same reference numeral and its description is omitted. Reference numeral 20 is a first control unit capable of controlling the operations of the preprocessing unit 2 and the encoder unit 4 by the switching signal of the mode switching unit 17.

The operation of the image communication terminal configured as described above will be described below. When the mode switching unit 17 is in the normal communication mode, the same operation as that of the conventional technique is performed, and thus the description thereof is omitted. Next, when the mode switching unit 17 switches the mode from the normal communication mode to the answering machine mode, the first control unit 20 inputs the switching signal from the mode switching unit 17 and detects that the mode has been switched. The next frame of the analog video input signal from the camera 1 at that timing is determined as still image message data of a still image to the other terminal, and the preprocessing unit 2 processes the target frame and writes it in the transmission frame memory 3. Put in. After the completion of the writing process, the first control unit 20 sends an operation stop control signal of the preprocessing unit 2 to stop the operation. After that, the first control unit 20
Sends a still image mode setting control signal to the encoder unit 4. With this control signal, the encoder unit 4 performs an encoder process on the digital video transmission signal of the target frame held in the transmission frame memory 3 and shifts to the still image mode to process the multiplexed video signal for transmission buffer memory. Hold at 5. By the above processing, the storage of the still image message data in the partner terminal in the answering machine can be completed. In this state, when a call is made from the other terminal to the own terminal, the own terminal automatically responds and sends the multiplexed video signal held in the sending buffer memory 5 as still image message data. In this way, the answering machine function can be realized.

Next, a second embodiment of the present invention will be described. Figure 2
FIG. 6 is a functional block diagram of an image communication terminal according to a second embodiment of the present invention. In FIG. 2, 1 is a camera, 2 is a pre-processing unit, 3 is a transmission frame memory, 4 is an encoder unit, 5
Is a transmission buffer memory, 6 is a multiplexing / demultiplexing unit, 7 is a network interface unit, 8 is a receiving buffer memory, 9 is a decoder unit, 10 is a receiving frame memory, 11 is a post-processing unit, 12 is a monitor, and 17 is The mode switching units are the same as those in the conventional example, and therefore, the same reference numerals are given and description thereof is omitted.

Reference numeral 19 is an image in which received data including still image message data from the other party in the answering machine mode is processed by the network interface unit 7, the multiplexing / demultiplexing unit 6 and the decoder unit 9 and the processed digital video received signal is accumulated. A storage memory 21 is a second control unit that controls the decoder unit 9 and the post-processing unit 11 according to a switching signal from the mode switching unit 17.

The operation of the image communication terminal configured as described above will be described below. When the mode switching unit 17 is in the normal communication mode, the same operation as that of the conventional technique is performed, and thus the description thereof is omitted. Next, in the state where the mode switching unit 17 has switched to the answering machine mode, when a call is made from the partner terminal to the own terminal, the own terminal automatically responds. The network interface unit 7 receives the received data including the still image message data from the partner terminal, and outputs the multiplexed received signal to the multiplexing / demultiplexing unit 6. Multiplexing / separating unit 6
Then, it is separated into a separated video signal and is temporarily held in the reception buffer memory 8. The second control unit 21 sets in advance the decoder unit 9 to decode the first frame of the image message data from the partner terminal and store it in the image storage memory 19 when the mode is switched to the answering machine mode. deep. Therefore, the decoder unit 9 reads the separated video signal from the receiving buffer memory 8 and judges whether the signal is the first frame of the image message data from the partner terminal, and if the data is the first frame. For example, the decoding process is performed only on the first frame. The decoded digital video reception signal is stored in the image storage memory 19 instead of the reception frame memory 10. In the above description, the first frame is described, but this may be the second frame or the third frame. By the above processing, the storage of the still image message data from the partner terminal in the answering machine can be completed.

Next, a third embodiment of the present invention will be described. FIG. 3 is a functional block diagram of the image communication terminal according to the third embodiment of the present invention. In FIG. 3, 1 is a camera, 2 is a pre-processing unit, 3 is a transmission frame memory, 4 is an encoder unit,
5 is a transmission buffer memory, 6 is a multiplexing / demultiplexing unit, 7 is a network interface unit, 8 is a receiving buffer memory, 9 is a decoder unit, 10 is a receiving frame memory, 11 is a post-processing unit, 12 is a monitor, 17 Is a mode switching unit. Since these are similar to the conventional example, the same reference numerals are given and description thereof is omitted.

Reference numeral 19 is an image in which received data including still image message data from the other party in the answering machine is processed by the network interface unit 7, the multiplexer / demultiplexer unit 6 and the decoder unit 9 and the processed digital video received signal is accumulated. A storage memory, 23 is a timing instruction unit for setting which frame is used as the own still image message data in the own terminal when the other terminal is in the answering machine mode, and 22 is the mode switching unit 17 and the timing instruction. Part 2
The third control unit controls the preprocessing unit 2, the encoder unit 4, and the decoder unit 9 by the signal of 3.

The operation of the image communication terminal configured as described above will be described below. When the mode switching unit 17 is in the normal communication mode and the timing instructing unit 23 is not controlled, the same operation as that of the conventional technique is performed, and the description thereof is omitted. Next, the operation of the terminal A when the mode switching unit 17 of the terminal A is in the normal communication mode and the terminal B is in the answering machine mode will be described. When the timing instruction unit 23 transmits the timing instruction signal to the third control unit 22, the third control unit 22 transmits the image capture control signal to the preprocessing unit 2. The preprocessing unit 2 converts the next frame of the currently input analog video input signal into a common intermediate format and temporarily holds it in the transmission frame memory 3. After that, the third control unit 22 sends an operation stop control signal to the pre-processing unit 2 and controls so as to stop the writing operation to the transmission frame memory 3. That is, the frame instructed by the timing instructing unit 23 is the frame memory for transmission 3
And the frame data is stored as the still image message data to be transmitted to the terminal B.

Then, together with the still image message data, a control signal for notifying the terminal B that the image data is the still image message data instructed by the timing instruction section 23 is transmitted to the terminal B. This method includes CCITT H. In the multiplexing / separating unit 6 that operates according to the H.221 recommendation, the H.264 standard is used. BAS (Bit-rate Allocati) not defined in 221
on Signal), the method of notifying the terminal B, the method of notifying using the voice channel, the method of notifying using the data channel, and the like are conceivable. Here, in the video signal multiplexing process in the encoder unit 4, a method of notifying by using the type information (PTYPE) in the frame layer (or assigning this control bit to other spare bits in the frame layer and notifying the terminal B) It is also possible to do). After the operation of the preprocessing unit 2 is completed, the third control unit 22 transmits a still image mode setting control signal to the encoder unit 4. The encoder unit 4 is controlled by this control signal.
Performs an encoding process on the digital video transmission signal of the target frame held in the transmission frame memory 3, shifts to the still image mode, and holds the processed multiplexed video signal in the transmission buffer memory 5. At this time, the fifth bit of the type information of the frame layer changes due to the video signal multiplexing process of the encoder unit 4 so as to indicate that it has transited to the still image state. Thereafter, the terminal A transmits the multiplexed video transmission signal to the terminal B through the multiplexing / demultiplexing unit 6 and the network interface unit 7 to the terminal B.

Next, the operation on the terminal B side will be described. The third control unit 22 of the terminal B constantly monitors the fifth bit of the type information in the frame layer of the separated video signal, which is the image message data transmitted from the terminal A, and the image message data from the terminal A is stopped. When the image mode is set, an image message data storage request signal is transmitted to the decoder unit 9, and the decoder unit 9 stores the image message sent from the terminal A in the image storage memory 19. By doing so, the terminal B can store the image message data from the terminal A at the optimum timing.

Next, a fourth embodiment of the present invention will be described. Figure 4
FIG. 9 is a functional block diagram of an image communication terminal according to a fourth embodiment of the present invention. In FIG. 4, 1 is a camera, 2 is a pre-processing unit, 3 is a transmission frame memory, 4 is an encoder unit, 5
Is a transmission buffer memory, 6 is a multiplexing / demultiplexing unit, 7 is a network interface unit, 8 is a receiving buffer memory, 9 is a decoder unit, 10 is a receiving frame memory, 11 is a post-processing unit, 12 is a monitor, and 17 is The mode switching units are the same as those in the conventional example, and therefore, the same reference numerals are given and description thereof is omitted.

An image storage 19 stores received data including image message data from the other party in the answering machine mode by the network interface unit 7, the multiplexer / demultiplexer 6 and the decoder unit 9 and stores the processed digital video reception signal. Memory, 24 is a third switching unit for connecting the multiplexed video signal output from the encoder unit 4 and the demultiplexed video signal output from the multiplexing / demultiplexing unit 6 to the receiving buffer memory 8, and 26 is a transmitting unit. A first switching unit 25 for connecting the digital video transmission signal from the credit frame memory 3 and the receiving frame memory 10 to the switching encoder unit 4, and 25 for the first switching unit 26 and the third switching unit according to the switching signal of the mode switching unit 17. The fourth control unit controls the switching unit 24 and the decoder unit 9 and monitors the remaining memory amount of the image storage memory 19.

The operation of the image communication terminal configured as above will be described below. When the mode switching unit 17 is in the normal communication mode, the same operation as that of the conventional technique is performed, and thus the description thereof is omitted. When the own terminal is in the answering machine, the image message data from the other terminal is stored in the image storage memory 19. Since this operation is the same as the above-mentioned operation, its explanation is omitted. The fourth control unit 25 monitors the remaining memory amount of the image storage memory 19, and when the remaining memory amount falls below a certain amount, the first switching unit 2
6 is switched to the receiving frame memory 10 side, and the third switching section 24 is switched to the encoder section 4 side. After that, the image message data received from the other party's terminal and stored in the image storage memory 19 is transferred to the receiving frame memory 10, and further, via the first switching unit 26, the encoder unit 4
The digital video reception signal is output to. The digital video reception signal is one that has been subjected to a common intermediate format in the encoder unit 4, and this signal is subjected to encoder processing again in the encoder unit 4. In this encoder processing, the quantization level is made coarser than the normal level and the data amount is compressed more than in the normal operation. The multiplexed video signal thus compressed in data is temporarily held in the reception buffer memory 8 via the third switching unit 24. The decoder unit 9 processes the separated video signal held in the receiving buffer memory 8 and stores it again in the image storing memory 19. The processing method in the decoder unit 9 is the first method for performing the same decoding processing as usual, the second method for performing the image data separation processing but not the common intermediate formatting, and the input separated video signal. A third method without treatment is conceivable. By performing such an operation, the data amount of the image message data can be compressed and the image storage memory 19 can be effectively used.

Next, a fifth embodiment of the present invention will be described. Figure 5
FIG. 9 is a functional block diagram of an image communication terminal according to a fifth embodiment of the present invention. In FIG. 5, 1 is a camera, 2 is a pre-processing unit, 3 is a transmission frame memory, 4 is an encoder unit, 5
Is a transmission buffer memory, 6 is a multiplexing / demultiplexing unit, 7 is a network interface unit, 8 is a receiving buffer memory, 9 is a decoder unit, 10 is a receiving frame memory, 11 is a post-processing unit, 12 is a monitor, and 17 is The mode switching units are the same as those in the conventional example, and therefore, the same reference numerals are given and description thereof is omitted.

An image storage 19 stores received data including image message data from the other party in the answering machine mode by the network interface unit 7, the multiplexing / demultiplexing unit 6 and the decoder unit 9 and stores the processed digital video reception signal. Memory, 24 is a third switching unit for connecting the multiplexed video signal output from the encoder unit 4 and the separated reception signal output from the multiplexing / separation unit 6 to the switching reception buffer memory 8, and 28 is a rear A second switching unit that connects the analog video output signal from the processing unit 11 and the analog video input signal from the camera 1 to the switching preprocessing unit 2, and 27 is a second switching unit 28 according to the switching signal of the mode switching unit 17. The fifth control unit controls the third switching unit 24 and the decoder unit 9 and monitors the remaining memory amount of the image storage memory 19.

The operation of the image communication terminal configured as described above will be described below. When the mode switching unit 17 is in the normal communication mode, the same operation as that of the conventional technique is performed, and thus the description thereof is omitted. When the own terminal is in the answering machine, the image message data from the other terminal is stored in the image storage memory 19. Since this operation is the same as the above-mentioned operation, its explanation is omitted. The fifth control unit 27 monitors the remaining memory amount of the image storage memory 19, and when the remaining memory amount falls below a certain amount, the second switching unit 2
8 to the post-processing unit 11 side, and the third switching unit 24
Is switched to the encoder section 4 side. After that, the image message data received from the other terminal and stored in the image storage memory 19 is transferred to the receiving frame memory 10 and converted into an analog video output signal by the post-processing unit 11 and further via the second switching unit 28. And output to the pre-processing unit 2 for common intermediate formatting. In the common intermediate format of the preprocessing unit 2, C is set in the normal communication mode.
IF format (352 dots x 244 lines) is created, but in this mode, QCIF format (17
(6 dots x 144 lines) to significantly reduce the amount of data. Thereafter, the digital video transmission signal subjected to the QCIF format is once held in the transmission frame memory 3 and is encoded by the encoder unit 4. In this encoder processing, a method of making the quantization level coarser than the normal level and compressing the amount of data by the normal operation, a method of performing the same processing as the processing in the normal communication mode, and the like can be considered. The multiplexed video signal thus processed is temporarily held in the reception buffer memory 8 via the third switching section 24. The decoder unit 9 processes the separated video signal held in the receiving buffer memory 8 and stores it again in the image storing memory 19. The processing method in the decoder unit 9 is the first method for performing the same decoding processing as usual, the second method for performing the image data separation processing but not the common intermediate formatting, and the input separated video signal. A third method without treatment is conceivable. By performing such an operation, the data amount of the image message data can be significantly compressed and the image storage memory 19 can be effectively used.

[0028]

As described above, the image communication terminal of the present invention is
Unlike the conventional example, a VTR for sending message and a VTR for receiving message are not used, and an image storage memory for storing still image message data and a simple control circuit are added to an image communication terminal without an answering machine function. Since it can be configured only by itself, it is very inexpensive and can be reduced in size. Further, by instructing the image message capture timing, the still image message can be received and stored at the optimum timing, so that the effective still image message data can be surely stored. Furthermore, since the amount of still image message data can be further compressed and stored again by using the preprocessing function and encoding function of the own side, it is possible to realize an image communication terminal that can efficiently use the image storage memory. it can.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an image communication terminal according to a first embodiment of the present invention.

FIG. 2 is a functional block diagram of an image communication terminal according to a second embodiment of the present invention.

FIG. 3 is a functional block diagram of an image communication terminal according to a third embodiment of the present invention.

FIG. 4 is a functional block diagram of an image communication terminal according to a fourth embodiment of the present invention.

FIG. 5 is a functional block diagram of an image communication terminal according to a fifth embodiment of the present invention.

FIG. 6 is a functional block diagram of a conventional image communication terminal.

[Explanation of symbols]

 1 camera 2 pre-processing unit 3 transmission frame memory 4 encoder unit 5 transmission buffer memory 6 multiplexing / demultiplexing unit 7 network interface unit 8 reception buffer memory 9 decoder unit 10 reception frame memory 11 post-processing unit 17 mode switching unit 19 Image storage memory 20 First control unit 21 Second control unit 22 Third control unit 23 Timing instruction unit 24 Third switching unit 25 Fourth control unit 26 First switching unit 27 Fifth control unit 28 Second switching unit

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Fumio Fukushige 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. A preprocessing unit for inputting a local analog video input signal from a local camera or the like and outputting a digital video transmission signal converted into a common intermediate format, and temporarily holding the input digital video transmission signal. A transmission frame memory, a digital video transmission signal from the transmission frame memory, an encoding unit that encodes according to a moving image compression algorithm and multiplexes the encoded image data, and an encoding unit that multiplexes A transmission buffer memory that temporarily holds the multiplexed video signal that has been generated, and a multiplexed video signal signal that is read from this transmission buffer memory that multiplexes various signals such as voice, multiplexed video signal, data, and system control signal. A multiplexer / demultiplexer for separating the multiplexed received signal from the other terminal, and the multiplexed multiplexer. A network interface unit for outputting the other party received signal inputted from the transmission signal inputted and outputs the transmission signal to the communication network and the communication network to the multiplexing / demultiplexing unit, the multiplexing /
A receiving buffer memory for temporarily holding the separated video signal output from the separating unit, and a decoder unit for separating and expanding the separated video signal from the receiving buffer memory according to a moving image compression algorithm and converting it into a common intermediate format. After receiving the digital video reception signal from the reception frame memory that holds the common intermediate-formatted digital video reception signal output from this decoder unit and outputting the analog video output signal to the monitor The communication unit includes a processing unit, a mode switching unit that switches between the normal communication mode and the answering machine mode of the own terminal, and a first control unit that controls the mode switching of each block under the control of the mode switching unit. Input from the local camera etc. when the mode is switched from the answering mode to the answering machine. Only the frame of the local analog video input signal is processed as still image message data to the other terminal and stored in the transmission buffer memory, and if there is an incoming call from the other terminal in the answering machine mode, the transmission is performed. An image communication terminal characterized in that the still image message data held in the credit buffer memory is transmitted to the other terminal. 2. An image storage memory for storing a digital video reception signal output from the decoder section is provided, and the own terminal holds still image message data from the other party in the answering machine mode and reproduces it when the answering machine mode is released. The image communication terminal according to claim 1, wherein the image storage memory stores predetermined frame data transmitted from the other party. 3. In communication between image communication terminals equipped with a timing instructing section for instructing a timing of capturing still image message data, when one terminal is in an answering machine, the other terminal uses the timing instructing section. One terminal indicates the timing of capturing still image message data to be stored, and further transmits the timing instruction signal to one terminal, and in one terminal, the timing instruction signal transmitted from the other terminal. 3. The image communication terminal according to claim 2, wherein the still image message data of the frame instructed by the timing instruction signal is constantly stored and stored in the image storage memory. 4. A preprocessing unit for inputting a local analog video input signal from a local camera or the like and outputting a digital video transmission signal converted into a common intermediate format, and holding the input digital video transmission signal. A transmission frame memory, a first switching unit capable of switching between a digital video transmission signal from the transmission frame memory and a digital video reception signal from the reception frame memory, and a digital signal from the first switching unit. An encoding unit that inputs and encodes a video signal, a transmission buffer memory that temporarily holds the multiplexed video signal encoded by this encoding unit, a multiplexed video signal that is read from this transmission buffer memory, and audio and multiplexed video signal,
Multiplexing that multiplexes various signals such as data and system control signals, and separates multiplexed reception signals from the other terminal
A demultiplexing unit, a network interface unit for outputting the multiplexed multiplexed transmission signal to a communication network and a counterpart reception signal input from the communication network to the multiplexing / demultiplexing unit, and an output from the multiplexing / demultiplexing unit. A receiving buffer memory that temporarily holds the separated video signal, a decoder unit that decodes the separated video signal from the receiving buffer memory, and a common intermediate formatted digital video reception signal that is output from the decoder unit. The receiving frame memory that holds it, the post-processing unit that reads the digital video received signal from this receiving frame memory, performs reverse common intermediate formatting, and outputs the analog video output signal to the monitor, and the normal communication mode of the local terminal Mode switching unit that switches between the answering mode and the answering mode, and the mode switching control of each block by the control of this mode switching unit. A control unit for performing the above, an image storage memory for storing a digital video reception signal from the other party in the answering machine mode, and a third switching for switching between the multiplexed video signal and the separated video signal and outputting to the reception buffer memory. In the normal communication mode, the first switching unit converts the digital video transmission signal to the third video signal.
Is switched to a multiplexed video signal, and in the answering mode, the first switching unit is controlled to switch to a digital video reception signal and the third switching unit to a separated video signal to control the image storage. When the remaining memory amount of the memory for use becomes less than a certain amount, the digital video reception signal already stored in the image storage memory is transferred to the reception frame memory and is transferred to the encoder unit via the first switching unit. This encoder unit performs processing such as making the quantization step coarser than in the normal communication mode to reduce the amount of image data, and returns it via the third switching unit and temporarily stores it in the reception buffer memory,
Furthermore, the image communication terminal is characterized in that the image storage memory is reused through the decoder unit to increase the remaining memory amount of the image storage memory and effectively use the image storage memory. 5. A second switching unit for switching between a local analog video input signal from a local camera or the like and an analog video output signal output from a post-processing unit is provided, and the second switching unit is provided in the normal communication mode. Is switched to an analog video input signal, and in the answering machine mode, the second
Is controlled to switch to an analog video output signal, and the digital video reception signal already stored in the image storage memory is received when the remaining memory amount of the image storage memory becomes less than a certain amount. To the frame memory for use, and the post-processing section switches the analog video output signal reverse-common intermediate format to the second switching section, and the pre-processing section converts the common intermediate format to QCIF format instead of CIF format. The QCIF-formatted digital video transmission signal is temporarily held in the transmission frame memory and input to the encoder section. In this encoder section, processing such as coarser quantization step than in the normal communication mode is performed. The amount of image data is reduced and the reception buffer is passed through the third switching unit. The image storage memory according to claim 4, wherein the image storage memory is held in a memory and further stored in the image storage memory through a decoder unit to increase the remaining memory amount of the image storage memory and to effectively use the image storage memory. Communication terminal.