JPH05328341A - Video telephone - Google Patents

Abstract

PURPOSE:To enable a speaker to set up picture quality and to display a moving image having natural motion on a screen. CONSTITUTION:A CPU 311 enters data for one frame from an original image stored in a block memory in an image compressing part 342 in accordance with a parameter stored in a set parameter storing part and judges compression data size. When the compression data size is less than 1K bytes, an image with less movement is judged and respective parameters are changed in a direction for improving picture quality (direction approaching the original image). When the compression data size is increased and exceeds 2K bytes, an image with much movement is judged and respective parameters are changed in a direction for deteriorating the picture quality. When the data size is 1K to 2K bytes, image compression is executed by the image compressing part 342 by means of current parameters.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a videophone, and more particularly to a videophone for displaying a moving image of natural movement on a screen.

[0002]

2. Description of the Related Art With the widespread use of ISDN (Integrated Services Digital Communication Network), videophones utilizing ISDN have been developed. In addition to a conventional telephone that performs only voice communication, this videophone is also capable of communicating a self-portrait of the caller and images of materials and the like. In such a videophone, a voice input from a handset is encoded and a CCD (Charge coupled device) is used.
) Etc., the image of the speaker captured by a camera is compression-encoded, and both are transmitted from the ISDN line via the ISDN communication control section. On the other hand, since the voice and image from the other party's speaker are also encoded and transmitted, they are decoded and the voice is output from the handset, and the decoded image is output to the display. There is.

Here, there is a limit to the amount of data that can be transmitted using the ISDN line, and it is currently 64 Kbit / sec. Therefore, in the current videophone, although it is a moving image, the image quality of the image to be transmitted is set to a value set by each maker in response to the characteristic of the image that the positions of the eyes, mouth, and face last time are slightly moved. Then, the image is picked up by the CCD so as to have the set image quality, or the set image quality is set by thinning out the data picked up by the CCD, and the image data is set to, for example, DCT (discret cosine transform) or Huffman. After being compressed by various data compression methods such as encoding, it is transmitted to the other party via the ISDN line together with the voice data.

[0004]

However, in the conventional videophone, the image quality to be transmitted is set to a constant value as described above. For this reason, the image quality is sacrificed when trying to show a fixed image such as a drawing to the other party or when talking in a state where the movement is relatively small. On the other hand, when a violent motion is captured, the amount of data increases and the number of frames that can be transmitted decreases, so that the motion is sacrificed in a state of frame advance. As described above, in the conventional videophone, since the amount of data that can be transmitted is limited, either the image quality or the movement is sacrificed. Therefore, a first object of the present invention is to provide a videophone in which a speaker can set the image quality. A second object of the present invention is to provide a videophone capable of displaying a moving image of natural motion on the screen.

[0005]

According to a first aspect of the present invention, in a videophone having a camera for taking an image and a display for displaying the image, and transmitting and receiving the image data together with the audio data, an analog signal is used. Conversion means for converting a video signal into digital image data, parameter setting means for setting parameters for fetching data from the original image data after conversion by the conversion means, and parameters for storing the parameters set by the parameter setting means Storage means, data capturing means for capturing data from the original image data according to the parameters stored in the parameter storage means, compression processing means for compressing the image data captured by the data capturing means, and The transmitting means for transmitting the image data compressed by the compression processing means is a videophone. By provided to achieve the first object. According to another aspect of the invention, in a videophone having a camera for capturing an image and a display for displaying the image and transmitting / receiving the image data together with audio data, an analog video signal is converted into digital image data. Conversion means, parameter setting means for setting parameters for fetching predetermined data from the original image data after conversion by the conversion means, parameter storage means for storing the parameters set by the parameter setting means, and this parameter storage Data capturing means for capturing data from the original image data according to the parameters stored in the means, compression processing means for compressing the image data captured by the data capturing means, and compression processing by the compression processing means Transmission means for transmitting image data, and image data compressed by the compression means A data amount detecting means for detecting the compressed data amount, and changing the parameter so as to reduce the image quality when the compressed data amount detected by the data amount detecting means is larger than a predetermined value, and the compressed data amount is smaller than the predetermined value. The second objective is achieved by providing the videophone with parameter changing means for changing the parameter so as to improve the image quality when it is small.

[0006]

According to the present invention, the image data such as a self-portrait photographed by the camera is displayed on the display, the parameters are set while watching the displayed image, and the speaker sets the image quality to be transmitted to the other party. ,change. The set parameters are stored in the parameter storage means. Then, the data acquired from the original image data according to the set parameters is compressed and transmitted to the other party's videophone. According to the second aspect of the present invention, the movement of the image data is further determined by the compressed image data amount, and the parameter for taking in the image data is changed so that the image quality becomes appropriate according to the movement. That is, when a static image or a small amount of motion is set, the image quality is set to be high, and when an image is large in motion, the image quality is reduced and the number of frames to be transmitted is increased to display a natural motion.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a videophone according to the present invention will be described in detail below with reference to FIGS. FIG. 1 shows the external structure of a videophone. As shown in FIG. 1, the videophone 10 includes a base 11, a handset 12 is arranged on the left side of the base 11, and a display support 13 is arranged on the right side.

The handset 12 is for making a call, and includes a microphone and a speaker (not shown). A speaker 14 and various operation keys 15 are arranged on the upper surface of the base 11. The operation keys 15 include a speaker volume knob 15 for adjusting the volume of the speaker 14.
1, a handset volume knob 152 for adjusting the volume of the handset 12, various function keys 153 associated with the telephone function,
Numeric keypad 154 for dialing, recording key 155 associated with TV function, privacy key 156, menu screen key 157 for displaying menus such as various mode settings
Various operation keys 15 such as are arranged.

A camera 16 composed of, for example, a CCD is arranged on the front side of the upper portion of the display support 13 so as to photograph the speaker. Further, a display 17 for displaying an image is attached to the side surface of the display support 13 on the handset 12 side. On the display 17, the image of the other party transmitted from the videophone of the other party is displayed and the operation key 1
The menu screen is displayed according to various modes designated by the operation of 5, and the image captured by the camera 16 and transmitted to the other party is displayed after being combined with the image of the other party. Various displays such as displaying predetermined message texts and icons (pictograms) alone or in combination with images are performed.

A VT (not shown) is provided on the rear side surface of the base portion 11.
VTR connection terminals 25a to 25d for connecting R26
Are arranged. VT connected to this connection terminal 25
R26 and camera 16 attached to videophone 10
A camera switching key 18 for switching between and is arranged on the right side surface of the display supporting portion 13. In addition, on the right side surface of the display support portion 13, a photographing condition switching key 19 for switching photographing conditions such as an aperture according to the brightness of a room photographed by the camera 16, a color of an image displayed on the display 17 (RGB ) Color adjustment knob 2 for adjusting
0 and the cap 21 are arranged at predetermined positions. The cap 21 is a screw (not shown) for fixing the display 17 to the display support 13.
Is for covering. Display 1
Reference numeral 7 is a display support portion 1 formed by a spring so as to be vertically rotatable about the center of the cap 21.
It is attached by a biasing force in three directions.

FIG. 2 shows a schematic configuration of a circuit of such a videophone. As shown in this FIG.
The videophone includes a central processing unit 31. This central processing unit 31 is a well-known CPU (central
processing unit) 311, a memory 312 including a ROM (read only memory) storing various programs and data for communication and a RAM (random access memory) serving as a working memory storing various data. I have it. In this RAM, for example, a telephone number of a person who can receive an incoming call in an incoming call restriction mode for restricting incoming calls other than a designated caller, which is set by operating the function keys 153 and the numeric keypad 154, a speed dial, and Various data such as various flags indicating states such as standby, outgoing call, incoming call, and communication are stored. The central processing unit 31 also includes a chipset 313 as a communication interface, and a key controller 314 that controls instruction signals input from various keys of the operation keys 15.

The central processing unit 31 is provided with a communication control unit 3 via a bus line (ISA bus) 32 such as a data bus.
3 and the image processing unit 34 are connected. Also,
Through the ISA bus 32, various information processing devices such as a personal computer, CAD (computer aided design), DTP (desk top publishing), etc. can be connected. The communication control unit 33 uses the I
It has an SDN connection terminal 331 and is connected to an ISDN line. The communication control unit 33 uses a communication control signal,
It controls transmission and reception of data such as voice data and image data. The image processing unit 34 controls communication of the image data supplied from the camera 16 and the VTR 26, and the image reproduction unit 341 that reproduces the compressed image data transmitted from the videophone of the other party via the communication control unit 33. An image compression unit 342 that performs compression processing for transmission by the unit 33 is provided.

The video telephone 10 further includes an image processing unit 34.
D / A (digital / analog) converter 3 connected to
6. Image combining unit 37 connected to the D / A conversion unit 36
Also, an audio controller 38 connected to the image synthesizer and the communication controller 33 is provided. The audio control unit 38 includes a voice input / output terminal 25 of the handset 12, the speaker 14, and the VTR connection terminal 25.
a, 25c and the chip set 313 are connected. The audio control unit 38 switches between audio switching, hold tone, and DTMF (dual tone multiplex freq).
uency), the speaker 14 and the volume of the handset 12 are adjusted.

The D / A conversion unit 36 converts the image data reproduced by the image reproduction unit 341 of the image processing unit 34 from a digital signal to an analog video signal (NTSC; national tel).
D / A section 36 to be converted to an evision system committee)
1 and A / D for converting an analog video signal supplied from the image synthesizing unit 37 into digital image data
A section 362 is provided. The digital image data converted by the A / D unit 362 is the image compression unit 3 of the image processing unit 34.
42.

The image composition section 37 includes an amplifier (AMP) 37.
1, picture-in-picture section 372, AMP3
73 and a changeover switch unit 374,
It is connected to the video input / output terminals 25b and 25d of the R connection terminal 25 and the display 17. AMP371 is
An analog video signal taken by the camera 16 or V
The analog video signal supplied from the VTR 26 via the TR connection terminal 25b is amplified. Both video signals are selected by the camera switching key 18 in FIG.
It is determined by the connection state of the changeover switch unit 374 by the switching operation of. The analog video signal amplified by the AMP 371 is normally supplied to the A / D unit 362, and when the image synthesizing function is designated by the operation key 15, the A / D unit 362 and the picture-in-picture unit 37 are displayed.
It is supplied to both of the two.

Picture-in-picture section 372
AMPs the image data supplied from the D / A unit 361.
Supply to 373. Further, when the image synthesizing function is designated to be operated by the operation key 15, a video signal supplied from the D / A unit 361 (a signal of an image transmitted from the videophone on the other end of the call) and an AMP 371 are supplied. Video signal (self-portrait or VTR taken by camera 16
The video signal supplied from 26) is synthesized according to the designated state of the operation key 15, and the synthesized video signal is AMP.
Supply to 373. AMP373 is supplied NTSC
The signal is amplified and supplied to the display 17. The display 17 displays the supplied video signal in color.

FIG. 3 shows a circuit configuration in the image processing section 34. As shown in FIG. 3, the image processing unit 3
The image reproduction unit 341 of No. 4 stores a first-in first-out FIFO memory 341a for storing image data supplied from the ISA bus 32, a Huffman decoding unit 341b for Huffman decoding the image data of the FIFO memory 341a, and a decoded image. Block memory 341 in which data is stored
c, a compression playback unit 341d that reads out image data stored in the block memory 341c and plays back image data compressed by motion compensation interframe prediction, DCT, or the like.

The block memory 341c has an area for two frames, alternately stores Huffman-decoded image data, and the area other than the area in which this image data is stored (the area of the previous frame). The image data is read from the area where the image data is stored) and is compressed and reproduced. Then, when the recording key 155 (FIG. 1) is pressed, the compressed image data before reproduction stored in the block memory 341c is supplied to the central processing unit 31 via the ISA bus 32 and stored in the memory 312. RAM
It is supposed to be stored in.

On the other hand, the image compression section 342 has a setting parameter storage section 342a in which parameters for setting image quality are stored, a block memory 342b in which digital image data supplied from the D / A conversion section 36 is stored, A compression unit 342c that compresses the image data stored in the block memory 342b by motion compensation interframe prediction, DCT, etc., a Huffman encoding unit 342d that further Huffman-encodes the compressed image data, and a buffer memory 3
42a. Setting parameter storage unit 342a
Is connected to the CPU 311 via the ISA bus 32, and when the caller specifies the image quality, the parameters specified by the caller or the other party's speaker are stored.
Further, it is set and changed automatically according to an instruction from the CPU 311.

Next, the operation of the embodiment thus constructed will be described. First, the normal operation of the videophone will be described. (1) Operation of main routine FIG. 4 shows the operation of the main routine. First, the main operation of the main routine will be described. That is,
In the main routine, the CPU 311 uses the memory 3
12 each state FG (flag) is detected and each processing is performed,
In that process, the predetermined state FG is changed to shift to the next process or the previous process. That is, normally, the outgoing call or incoming call is monitored by repeating the waiting process, and when the outgoing call or incoming call is detected, a predetermined FG is changed, and then the process shifts to the corresponding process. In the outgoing / incoming processing, when the normal processing is performed, the processing shifts to the in-communication processing. Then, when the processing during communication is completed, or when a specific operation or the like is performed in the incoming or outgoing call processing,
Return to the waiting process and monitor the outgoing or incoming call again.

Next, the details of the main routine are shown in FIG.
Follow the instructions below. That is, when the videophone 10 is installed, the ISDN board (communication control unit 33), image processing board (image processing unit 34), keyboard (operation key 1)
5) and the image composition board (picture-in-picture section 372) is initialized and various memory areas are initialized (step 10). When the operator of the videophone processes the operation keys such as the function key 153 and the numeric keypad 154 (step 11), the CPU 3
11 shifts to DI / O processing and accepts output of control signals to each board and supply of status signals from each board (step 12).

Then, the CPU 311 accesses the flag storage area of the RAM in the memory 312, confirms whether any of the flags is in the ON state, executes the process corresponding to the flag in the ON state, and goes to a predetermined part. The instruction signal of is output. That is, the CPU 311 shifts to the standby process (step 14) when the standby FG is ON (step 13), and shifts to the outgoing call process (step 16) when the outgoing FG is ON (step 15). When the incoming FG is ON (step 17), the incoming process is performed (step 18), and when the communicating FG is ON (step 19), the incoming process is performed (step 2).
0). Then, when all the flags are OFF, and after any of the processes from step 14 to step 20 is completed, the process returns to step 11 to continue the process.

(2) Waiting process FIG. 5 shows the operation of the waiting process. CPU3
11 monitors an incoming call when the handset 12 is on-hook, the display 17 is off, and there is no call, and when there is an incoming call (step 141; Y), the memory 312 waits in order to shift to the incoming call process. Medium FG is O
At the same time as changing the N state to the OFF state, the incoming FG is changed from the OFF state to the ON state (step 14
2) Return the process. As a result, the process proceeds to the incoming call process (step 18) in FIG. on the other hand,
When there is no incoming call (step 141; N), the state of the handset 12 is judged. The CPU 311 detects the off-hook of the handset 12 (step 143;
Y), the standby FG of the memory 312 is changed from the ON state to the OFF state in order to shift to the transmitting process, and
The transmission FG is changed from the OFF state to the ON state (step 144). As a result, the process proceeds to the calling process (step 16) shown in FIG.

In step 143, the handset 1
When 2 does not detect the off-hook and is in the on-hook state (step 143; N), the CPU 311 determines whether or not a key input is made by the operation of the operation key 15 (step 145). (Step 14
5; N), the process is returned. On the other hand, when the key input is performed (step 145; Y), when the input key is the speaker key input (step 146;
Y), shift to step 144, and change the flag for shifting to the calling process. In this case, by inputting the speaker key, the handset 12 is transmitted while being on-hook. If the input key is other than the speaker key (step 146; N), for example, a menu, self-portrait, incoming call restriction, etc. are set as each functional process corresponding to the input key (step 147), and the process is returned. ..

(3) Call origination process FIG. 6 shows the operation of the call origination process. This calling process is started when the calling FG is changed to the ON state in the waiting process of FIG. 5 (step 144). Since the processing is the same as that of a normal key telephone device, only the outline thereof will be described. First, in the outgoing state (step 161; N), there is a dial key input 162; Y), and from this dial key input, 4
When the second has elapsed (step 165; Y), or when the function key has been entered before the elapse of 4 seconds and the second digit key has been entered using the speed dial (step 167; Y), or the call key has been entered. If yes (step 168; Y), the calling process is performed. That is, as the calling process, the fact that the call is being made is displayed on the display 17, and the ISDN
The communication control unit 33 processes the outgoing connection to the line network. After that, the outgoing FG is turned on as the status FG change process.
The N state is changed to the OFF state, and the transmitting FG is changed from the OFF state to the ON state (step 170).
Change the status from outgoing to outgoing.

On the other hand, in the outgoing state (step 16
1; N), there is a dial key input, 4 seconds have not elapsed (step 166; Y), and it is not a speed dial, or the speed dial is in the first digit and the call key is not pressed (step). 167; N, step 16
8; N), the input numeric key (step 171; Y)
Accordingly, only the dial key input processing is performed (step 172).

Then, in the outgoing state (step 16
1; N), if 20 seconds have elapsed without any dial key input (step 173; Y), a call-out time-out process is performed (step 174). That is, as the transmission time-out process, the display 17 is turned off,
The speaker 14 or the speaker of the handset 12 is switched from dial tone (two) to busy tone (two, two, ...).

When the calling FG is changed to the ON state in step 170, the process returns from step 161 to step 175, and it is monitored whether or not a connection response is made from the dialed party. If there is a response (step 175; Y), the calling FG set in step 170 is changed from the ON state to the OFF state, and the communicating FG is transmitted.
After changing from the OFF state to the ON state (step 17
6) By the return process, the process proceeds to the in-communication process (step 20) in FIG. On the other hand, if there is no response from the other party (step 175; N) and the handset 12 in the off-hook state is on-hook (step 17).
7; Y), while sending FG is turned off, waiting F
G is changed to the ON state (step 178), and by the return processing, thereafter, the standby processing in FIG. 4 (step 1
Go to 4).

(4) Processing during incoming call FIG. 7 shows the operation of the processing during incoming call. This incoming call process is the waiting process of FIG.
The process is started by changing to the N state (step 142). The CPU 311 determines whether or not the operation is in the incoming call restriction mode by operating the operation keys 15.
It is judged from the incoming call restriction FG of No. 2 (step 181). In the incoming call restriction mode (step 181;
Y), the telephone number of the calling party is set and stored in a, and the memory 312 is set in advance by operating the operation key 15.
The incoming call restriction registration number registered in is set to b (step 182).

Then, the CPU 311 compares the set telephone numbers a and b with each other and makes a telephone number a of the calling party.
However, if it does not match any of the registration numbers b that allow incoming calls (step 183; N), disconnection processing is performed on the calling party via the communication control unit 33 (step 18).
4). Thereafter, the incoming call flag is changed to the OFF state and the standby FG is changed to the ON state (step 18
5) By the return process, the process shifts to the waiting process (step 14) in FIG.

On the other hand, in the incoming call restriction mode, if the telephone number a of the calling party matches any of the registered numbers b (step 183; Y), or if the incoming call restriction mode is not in effect (step 181; N). If the termination of the incoming call processing is not instructed (step 186; Y), the call setting is performed, the ringer is sounded, and the display 17
Incoming processing such as terminating the incoming message is performed (step 187). And the hook switch is off
If so (step 188; Y), a callable state is set to the ISDN line via the communication control unit 33 (step 189). After that, the CPU 311 uses the memory 312.
The incoming call FG is changed from the ON state to the OFF state, and the communicating FG is changed from the OFF state to the ON state (step 190). Then, by the return process, the process shifts to the call process (step 20) in FIG. To do.

(5) Processing during communication FIG. 8 shows an operation of processing during communication. In this communication process, the communication FG is ON in the transmission process of FIG.
The process is started by changing the state (step 176) or changing the communicating FG to the ON state in the incoming call process of FIG. 7 (step 190).
First, the CPU 311 monitors whether or not the calling party has issued a communication disconnection request to the communication control unit 33 via the ISDN line (step 201). If there is no disconnection request (step 201; N), the handset 12 is on-hook (step 202; Y), and the hold key or speaker key has been pressed in advance (step 20).
3; Y), each function processing that is effective even during a call, such as hold and transmission pause, is performed (step 204).

That is, the following processes are performed as the respective functional processes. Hold process ... When the hold key of the function keys 153 is pressed, the hold screen is displayed on the display 17, and the hold screen data is transmitted from the communication control unit 33 to the ISDN line.
As the hold screen data, image data captured by the camera 16 in advance or supplied from the VTR 26 is stored in the RAM of the memory 312, and this image data is read and used. When the hold screen setting is the default (the one prepared as standard and not rewritable), only the hold code is transmitted, and the side receiving the code displays the default screen on the display 17.

Transmission pause process: When the transmission pause key is selected, a screen having no correlation with the previous frame is captured from the image data supplied from the camera 16 or the like and displayed on the display 17, and the image data is communication-controlled. It is transmitted from the part 33 to the other party. Further, the display 17 displays an icon indicating the paused state.

Privacy processing ... Privacy key 1
When 56 (FIG. 1) is pressed, the corresponding code is transmitted to the other party of the call via the communication control unit 33, and the icon indicating the privacy state is displayed on the display 1
Display on 7. On the other hand, in the videophone that has received the privacy code, the privacy screen is displayed on the display 17.

Recording process: When the recording key 155 is pressed, a request is made to the videophone of the other party to send image data having no correlation with the previous frame. Then, when receiving image data that has no correlation,
The received image data is kept in the compressed state, or the image data after being reproduced by decoding is stored in the memory 3
It is stored in the RAM 12 and recording is started. In addition, VTR
26 is connected, the compressed image data is reproduced and converted into an analog video signal by the D / A unit 361 shown in FIG. 2, and then the AMP 373 and VTR connection terminal 25 are connected.
You may make it record on VTR26 via d. In this case, since the image displayed on the display 17 is recorded as it is, the correlation of the transmitted image data does not matter.

Menu processing ... Menu screen key 157
When is pressed, a recording medium selection icon is displayed on the display 17, and one-shot recording for recording a screen of only a certain specific frame or tape selection is possible. In the case of one-shot recording, when a request to send image data with no frame correlation is sent to the other party's videophone and image data with no correlation is received, the image data remains compressed or played back for decoding, etc. The subsequent data is stored in the memory 312.

Image processing: As will be described later in detail,
The outline will be described here. When the self-portrait processing is selected, the display 17 does not display the image data transmitted from the other party's videophone, but the camera 16 or the VTR 2
The self-portrait imaged in 6 is displayed on the display 17.
The caller sets and changes the screen size and the image quality mode while looking at the self-portrait displayed on the display 17. This image quality mode includes a designated image quality mode in which image data is transmitted at a designated constant image quality, and an automatic image quality mode in which the movement of the image data is monitored and an appropriate image quality of the self image according to the movement is selected. On the other hand, when the partner image processing is selected, the partner image processing screen is displayed on a part of the display 17 on which the partner image is displayed. The caller specifies the screen size of the partner image and the image quality mode of the partner image according to the instruction on the partner image processing screen while looking at the partner image displayed on the display 17. When the image quality mode of the partner image is designated, the CPU 311 transmits a corresponding control signal from the communication control unit 33 to the partner videophone.
On the other party's videophone, when this control signal is received,
Change to the specified image quality.

After completion of each functional process described above, the image communication process is performed (FIG. 8, step 20).
5). That is, when the ISDN board (communication control unit 33) is in a state of data transmission OK, the image control unit 3 acquires the image data, attaches a communication header to each transmission block,
Send from 3. If there is received data in the communication control unit 33, it is received, and the image data is displayed on the display 17 via the image processing unit 34, the D / A conversion unit 36, and the image synthesis unit 37 for each frame of image data. .. The received voice data is output to the handset 12, the speaker 14, or the VTR connection terminal 25a via the audio control unit 38.

In step 202, when the handset 12 is off-hook (step 202;
N), it is determined whether or not a predetermined key input is made from the operation keys 15 (step 206). If a key input is made (step 206; Y), the process proceeds to each functional process of step 204, and if no key input is made (step 20).
In 6; N), the process proceeds to the image communication process of step 205.

On the other hand, in step 201, the other party issues a disconnection request (step 201; Y), and if it is normally completed (step 207; Y), or in step 203, both the hold key and the speaker key. If it has not been pressed in advance (step 203; N), C
The PU 311 performs communication end processing (step 20).
8). That is, as the communication end process, the handset 1
The videophone on the side that hooked 2 sends a disconnection message to the voice line, and sends a disconnection message to the data line when release is returned. On the other hand, the videophone on the disconnected side sends out the data disconnection message when receiving the audio disconnection message. Here, the display 17 on the calling side displays the charge and the call time, and the display 17 on the receiving side displays only the call time.

After that, the CPU 311 sets the communication FG in the ON state to the OFF state and changes the standby FG in the OFF state to the ON state (step 209), and thereafter, by the return processing, the standby processing in FIG. Go to (Step 14). At step 207, as in the case where an error occurs in the image data line, if the process is not completed normally (step 207; N), communication error processing is performed (step 210). That is, as the communication error processing, the line of the image data is disconnected and only the voice communication is performed.
In this case, the display 17 displays only a predetermined image stored in advance in the RAM and also indicates that there is a communication error.

Next, the transmission / reception operation of image data during the communication processing will be described with reference to FIGS. 2 and 3. Self-portrait taken by camera 16 or VTR2
The video signal of the video supplied from 6 is amplified by the AMP 371 and then supplied to the D / A conversion unit 36. Here, the analog video signal is converted into digital image data by the A / D unit 362 and then supplied to the image processing unit 34.

The image data supplied to the image processing unit 34 is stored in the block memory 342b as original image data. The compression unit 342c takes in predetermined data from the original image data stored in the block memory 342b according to the parameters stored in the setting parameter storage unit 342a. Then, the captured image data is subjected to motion compensation inter-frame prediction, image compression by DCT or the like. The compressed image data is further Huffman encoded and sequentially stored in the buffer memory 342e. The image data stored in this buffer memory 342e is
Taken into the central processing unit 31 via the ISA bus 32,
Further, via the ISA bus 32 from the communication control unit 33 to the ISD
Sent to N lines. The transmitted image data is reproduced on the videophone of the other party and displayed on the display 17.

On the other hand, the image data from the other party's videophone received by the communication control unit 33 is supplied to the central processing unit 31 via the ISA bus 32. Since this image data has been compressed by the other party's videophone, it is sequentially supplied to the image reproducing unit 341 for reproduction by a method opposite to that compressed by the image compressing unit 342. Image reproduction unit 341
Image data supplied to the FIFO memory 341 sequentially.
After being stored in a and decoded by the Huffman decoding unit 341b, they are stored in the block memory 341c in frame units. The data stored in the block memory 341c is reproduced by the IDTC or the like in the compression reproduction unit 341d and supplied to the D / A conversion unit 36. The image data before compression reproduction stored in the block memory 341c is supplied to the central processing unit 31 through the ISA bus 32 when the recording key 155 is pressed, and the memory 312 is stored.
Is stored in the RAM and saved.

The digital image data supplied to the D / A conversion unit 36 is converted into an analog video signal by the D / A unit 361, and the picture-in-picture unit 372.
Then, if necessary, it is combined with the video signal of the self-portrait supplied from the camera 16 or the like, supplied to the display 17 via the AMP 373, and displayed.

Next, the operation of changing the image quality and size of the self image and the partner image will be described. When it is desired to change the image quality and size of the image of the user or the other party during communication, image quality change processing or size change processing is performed. If the image quality is reduced and the size is reduced, the amount of data per sheet becomes smaller,
The number of frames that can be transmitted per second increases, and becomes closer to a moving image. Conversely, if you improve the image quality and increase the size,
The amount of data per sheet becomes large, and a still image is displayed frame by frame. Therefore, in this embodiment, the image quality and the size can be freely changed according to the purpose of communication with the other party, and the optimum images that meet the needs can be mutually selected.

FIG. 9 conceptually illustrates each state of the image quality and size conversion processing. The image quality and size conversion is performed by fetching predetermined data from the original image data stored in the block memory 342b according to the parameters stored in the setting parameter storage unit 342a. FIG. 9A shows the block memory 34.
2b shows the state of the original image data stored in 2b. As shown in FIG. 9A, the original image data is 6
It is composed of 153600 pixels each consisting of 40 dots × 240 lines. And each pixel is RG
5 bits of data for each B (red, green, blue) 3
There are two levels of gradation.

Then, with respect to this original image, line skipping for fetching data every other line according to the parameter set in the setting parameter storage unit 342a (FIG. 9B), and data every other pixel are acquired. Pixel skipping (Fig. 9 (c)), designated start pixel, end pixel, start line, size designation for fetching data in the area surrounded by end line (Fig. 9 (c)), pixel of original image data The translation (FIG. 9 (d)) that takes in 2/3 is executed. The image quality is also changed by changing various filter setting values. That is, the color hierarchy of the captured image, the change of the threshold value with respect to the color change, the threshold value of whether or not to consider the same when correlating each block, and the like are changed.

FIG. 10 shows the operation of image processing. This image processing corresponds to the image processing in each functional process (step 204) of the in-communication process shown in FIG. The CPU 311 confirms the image quality mode regarding the setting of the image quality of the image data to be transmitted / received, and when it is the designated image quality mode (step 301; N), determines which of the partner image and the self image is to be designated (step 302,
Step 303).

When the image quality of the partner image is changed (step 302; Y), partner image processing is performed (step 30).
4). That is, the partner image processing screen is displayed on a part of the display 17 on which the partner image is displayed. The caller specifies the screen size of the partner image and the image quality of the partner image according to the instruction on the partner image processing screen while looking at the partner image displayed on the display 17, by setting each parameter described in FIG. That is, line skip, pixel skip, size specification, translate,
The image quality of the partner image is specified by specifying changes in various filter setting values. When each parameter of the partner image is specified,
The CPU 311 transmits from the communication control unit 33 to the other party's videophone. The central processing unit 31 of the other party's videophone,
The setting parameter storage unit 342a (FIG. 3) is changed to the designated parameter, and thereafter, the compression unit 342c compresses the image data according to the changed parameter.

On the other hand, when the change of the image quality of the self-portrait is designated (step 303; Y), the self-portrait process is performed (step 305). That is, the self-portrait captured by the camera 16 or the VTR 26 is displayed on the display 17 which was displaying the partner image. Caller, display 1
While looking at the self-portrait displayed in 7, each parameter such as line skip is set. Each set parameter is
It is stored in the setting parameter storage unit 342a. After that, the compression unit 342c takes in the image data of the block memory 342b and performs the compression process according to this parameter.

When the automatic image quality mode is set in step 301 (step 301; Y), the CPU
311 performs automatic image quality processing (step 306). The automatic image quality processing in the automatic image quality mode is based on the following principle. That is, when the compression process is performed on the original image to capture one frame of data, and when the data size is small, it is determined that the image has little motion, and each parameter is changed to improve the image quality. On the contrary, when the data size after the compression process becomes large, the parameter is changed so as to reduce the image quality.

In this case, for example, 64K [bit / sec]
If you want to communicate image data with one ISDN line,
Data communication of up to 8K [bytes / second] is possible. Generally, to display a moving image, it is necessary to display an image of 4 to 8 frames per second, and the amount of transmission data per frame needs to be within 1 to 2 K [bytes].
In the present embodiment, if the data amount is 1 K [bytes] or less, the parameters are automatically changed to improve the image quality,
If it is 2K [bytes] or more, the parameter is automatically changed so as to reduce the image quality, so that 4 to 4
It is possible to approach the transfer rate of 8 frames.

FIG. 11 shows the image quality changing operation in the automatic image quality mode. The CPU 311 takes in one frame of data from the original image in the block memory 342b according to the parameters currently stored in the setting parameter storage unit 342a (step 311), and determines the compressed data size (step 312). When the compressed data size is 1 K [bytes] or less, it can be determined that the image has little movement, and therefore the parameters currently stored in the setting parameter storage unit 342a are read (step 313). Then, each parameter is changed so as to improve the image quality (direction closer to the original image) than when compressed by the read parameter (step 314).

On the other hand, the compressed data size becomes large and becomes 2K.
If it exceeds [bytes], it can be determined that the image has a lot of movement. In this case, if the image is compressed and transmitted according to the current parameters, the number of frames that can be transmitted per second is reduced, and an unnatural moving image with frame advance is obtained. Therefore, the current setting parameters are read (step 315), Each parameter is changed so as to reduce the image quality (step 31).
6). Regarding the relationship between the image quality and the parameter, the highest image quality is the original image, and in this case, all the parameters are turned off. Then, when the image quality is lowered, a predetermined image quality is set by combining the respective parameters.

In step 312, if the compressed data size is 1 to 2 K [bytes], the image is compressed with the current parameters and the movement of the image is continuously monitored by the return process.

In the embodiment described above, the image processing unit 34
Although the DCT has been described as an example of the compression processing of the image data by the above, the present invention is not limited to this method, and for example, slope coding, vector quantization, motion compensation interframe coding, predictive coding, Hierarchical vector quantization, FST (Four Square Transform) may be used, or a combination of these may be combined for compression processing.

[0058]

According to the video telephone set forth in claim 1, since the image quality transmitted to the other party is set and changed by the parameter setting means, the image data transmitted by the caller (still image such as drawing or , An appropriate image quality can be selected according to a self-portrait with a large amount of movement. According to the videophone of claim 2, further, the movement of the image data is judged by the compressed image data amount, and the parameter for taking in the image data is automatically changed so as to obtain an appropriate image quality according to the movement. Therefore, a moving image with natural movement can be displayed on the screen.

[Brief description of drawings]

FIG. 1 is an external configuration diagram of a videophone according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of the videophone of the above.

FIG. 3 is a block diagram showing details of an image processing unit of the above.

FIG. 4 is a flowchart showing the operation of the main routine of the videophone.

FIG. 5 is a flow chart showing an operation of a standby process of a videophone in the same as above.

FIG. 6 is a flowchart showing an operation of a videophone call process of the above.

FIG. 7 is a flowchart showing the operation of the process during the incoming call of the videophone.

FIG. 8 is a flowchart showing the operation of the processing during communication of the videophone.

FIG. 9 is an explanatory diagram conceptually showing each state of image quality and size conversion processing of the videophone.

FIG. 10 is a flowchart showing the operation of image processing of the videophone according to the above.

FIG. 11 is a flowchart showing the image quality changing operation in the automatic image quality mode of the videophone.

[Explanation of symbols]

 10 Videophone 11 Base Part 12 Handset 13 Display Support 14 Speaker 15 Operation Key 16 Camera 17 Display 18 Camera Switch Key 19 Shooting Condition Switch Key 20 Color Adjustment Knob 21 Cap 25 VTR Connection Terminal 31 Central Processing Section 311 CPU 312 Memory 32 ISA bus 33 Communication control unit 34 Image processing unit 341 Image reproducing unit 342a FIFO memory 342b Huffman encoding unit 342c Block memory 342d Compression reproducing unit 342 Image compressing unit 342a Setting parameter storage unit 342b Block memory 342c Compressing unit 342d Huffman encoding unit 342e Buffer memory 36 D / A converter 37 Image synthesizer 38 Audio controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoki Kubota 1-10-10 Higashigotanda, Shinagawa-ku, Tokyo Office Building T & U 7F AW Newhard Co., Ltd.

Claims (2)

[Claims] 1. A video telephone which has a camera for taking an image and a display for displaying the image, and which transmits and receives the image data together with the voice data, converts the analog video signal into digital image data. A parameter setting means for setting parameters for fetching data from the converted original image data in the converting means, a parameter storage means for storing the parameters set by the parameter setting means, and a parameter storage means for storing the parameters. Data capturing means for capturing data from the original image data in accordance with the parameter, compression processing means for compressing the image data captured by the data capturing means, and image data compressed by the compression processing means A videophone, comprising: a transmission means. 2. In a videophone having a camera for taking an image and a display for displaying the image, and transmitting and receiving the image data together with the audio data, a conversion means for converting an analog video signal into digital image data. A parameter setting means for setting a parameter for fetching predetermined data from the converted original image data in the conversion means, a parameter storage means for storing the parameter set by the parameter setting means, and a storage for the parameter storage means. Data capturing means for capturing the data from the original image data according to the parameter being stored, compression processing means for compressing the image data captured by the data capturing means, and image data compressed by the compression processing means. Transmitting means for transmitting, and compression of the image data compressed by the compressing means Data amount detecting means for detecting the data amount, and the parameter is changed so as to reduce the image quality when the compressed data amount detected by the data amount detecting means is larger than a predetermined value, and the compressed data amount is smaller than the predetermined value. And a parameter changing unit for changing the parameter so as to improve the image quality when the size is small.