JPH09130767A - Image transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply higher image quality coding to a specific image area than other areas in the image coding. SOLUTION: An image identification separate section 1041 of an image CODEC 104 divides a received image into two image areas, the resolution of the image area not requiring high image quality is converted into low resolution by a resolution conversion section 1042 to reduce the data quantity and the image in the image area to be subjected to high image quality coding is coded while keeping high resolution. Furthermore, timers (1) 1047, (2) 1048 count respectively the coded time interval of the high image quality area and the low image quality area to increase number of frames of the high image quality area more than that of the low image quality area thereby smoothing a motion represented by the high image quality area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transmission apparatus for transmitting a moving image or a still image, and more particularly to a predetermined region in an image to be transmitted or a region designated by a terminal for receiving the image. The present invention relates to an image transmission device capable of high quality transmission.

[0002]

2. Description of the Related Art In recent years, with the development of image compression technology and the like, image transmission systems using communication lines with a low data transmission rate such as INS64 and public telephone networks have been commercialized. An example of such a product is a TV telephone system. In such a system, data compression techniques such as motion compensation and DCT are used to compress image data to be transmitted so that images can be communicated within the transmission speed of a communication line.

Incidentally, such an image transmission system is described in, for example, Japanese Patent Publication No. 6-83444.

[0004]

When image data is compressed, motion compensation or DCT is usually used. on the other hand,
When image transmission is performed through a communication line having a low transmission rate such as a telephone line, the image data compression rate must be increased.

In the conventional image transmission apparatus, since these methods are used evenly in any part of the image to be compressed, the deterioration of the image quality due to the data compression occurs equally regardless of the central part or the peripheral part of the image. Was there. Therefore, when the compression rate is increased, the image quality is deteriorated over the entire image, which causes a problem that the transmitted image is difficult to see.

By the way, when communicating with the other party via the TV telephone, the object of interest (for example, the figure or face of the other party of communication) in the image received by the user is located in the center of the image. In many cases, the periphery of the image is less important to the user.

Therefore, an object of the present invention is to, when compressing and coding an image to be transmitted, change the coding speed between the central part and the peripheral part of the image so that the coding speed of the central part of the image is By making it relatively faster than the peripheral part, the image quality of the central part of the image is improved compared to that of the peripheral part, and the encoding speed of the peripheral part of the image is reduced to improve the data compression rate of the image. The purpose is to enable high-quality images to be transmitted even on a communication line with a high transmission rate. As a result, it is possible to increase the resolution in the central portion of the image as compared with the peripheral portion, or to increase the number of times the image data is updated per fixed time.

It is another object of the present invention that the user on the receiving side sets an image area whose image quality is desired to be improved by operating the receiving terminal, and communicates this setting information to the terminal for transmitting the image,
By changing the encoding method according to the setting information at the transmission side terminal, the image area desired by the receiver side can be made high in quality.

[0009]

In order to achieve the above object, the image transmission apparatus according to the present invention, in image encoding, encodes an image region to be encoded with high quality from an image to be transmitted and an image with low quality. Image identifying / separating means for identifying the image area to be encoded and separating them, and resolution conversion for converting the resolution of the image area of the separated image to be encoded to low quality to a resolution lower than the original resolution. Means, or
First counting means for counting the time interval for encoding and updating the image data of the high-quality image area in the time interval for performing the image encoding of each area, and encoding and updating of the image data of the low-quality image area Second counting means for counting the time interval to be performed is provided.

Further, in the case of having a function of setting an image area for a high quality image from the receiving terminal side to the transmitting terminal side,
In addition to the above-mentioned means, an instruction means used for setting an area of a transmitted image to be a high-quality image and setting an update time interval of image data, and the set image setting information. A communication means for transmitting to the transmission side terminal, receiving and detecting the image setting information communicated from the partner terminal, and controlling the image identification separating means and the resolution converting means or the counting means according to the detected image setting information, And control means.

In the structure provided with each of the above means, the input image data is separated by the image identification separation means into image area data to be encoded in high quality and image area data to be encoded in low quality. Then, the data of the low-quality image area is converted into the low resolution by the resolution conversion means to reduce the data amount, and thereafter the data of each area is compression-coded and transmitted to the partner terminal. Alternatively, after the image divided into the high-quality image area and the low-quality image area by the image identification / separation means is encoded, the counting operation of the first counting means and the second counting means is started, and the first counting is performed. When the means counts the predetermined time, the high-quality image area of the newly input image data is encoded, the counting operation of the first counting means is started again, and the second counting means When the predetermined time is counted, the low-quality image area of the newly input image data is coded and the counting operation of the second counting means is started again. Such counting operation and encoding are repeated, and the compression-encoded image data thus obtained is transmitted to the partner terminal. In this case, the time interval counted by the first counting means is set to a value different from the time interval counted by the second counting means.

Further, when the image coding is set on the receiving side, the receiving terminal side uses the instructing means to set the range of the image area of the image to be communicated having high quality and the update time interval of the image data. After the setting, the image setting information is transmitted to the transmitting side terminal by the communication means. Then, in the transmission side terminal, the control means controls the image identification separation means and the resolution conversion means or the counting means according to the image setting information.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a block diagram showing a configuration of a terminal device in a videophone system according to the first embodiment of the present invention.

In FIG. 1, reference numeral 101 is a system control unit configured by a microcomputer or the like for controlling the entire terminal device, 102 is a camera for taking an image to be transmitted, and 103.
Is an A / D converter for converting an image signal from the camera 102 into digital data, 104 is an image CODEC for encoding and decoding image data, 105 is a handset used when a user makes a call, and 106 is A / D converter for converting analog voice signals into digital data, 10
Reference numeral 7 is a D / A converter for converting the decoded audio data into an analog audio signal, 108 is an audio CODEC for encoding and decoding the audio signal, and 109 is for converting the decoded image data into an analog signal. D / A converter, 110 is a display for displaying received and transmitted images, 111
Is an operation unit including switches and dial buttons for performing various settings of the terminal device, 112 is a communication control unit for performing communication control,
Reference numeral 113 denotes a line interface (hereinafter referred to as line I / F) for connecting the terminal device to the communication line 114, 114
Is a communication line for transmitting image data and audio data, 115
Is a memory for storing various setting values and used as a work area of a program for operating the terminal device. As the display device 110, for example, a television monitor or a liquid crystal display device is used. A telephone line or an ISDN line is used as the communication line 114.

In the device according to FIG. 1, the system control unit 10
1 communicates with the other terminal via the communication control unit 112, and can be used as a videophone. The image captured by the camera 102 is the A / D converter 10
3 is converted into a digital signal and the image CODEC1
After being compressed and encoded by 04, it is sent to the communication control unit 112. The voice signal received by the microphone of the handset 105 is converted into a digital signal by the A / D converter 106, compression-coded by the voice CODEC 108, and then sent to the communication control unit 112. Communication control unit 1
Reference numeral 12 multiplexes the image data from the image CODEC 104, the audio data from the audio CODEC 108, and the communication control data from the system control unit 108, and the line I /
It is transmitted to the partner terminal device via F113 and the communication line 114.

In the terminal device on the receiving side, the communication control unit 112
Receives the multiplexed signal transmitted from the transmission side terminal via the communication line 114 and the line I / F 113, and separates it into communication control data, image data, and audio data.
Then, the communication control data is sent to the system control unit 101, the image data is sent to the image CODEC 104, and the audio data is sent to the audio CODEC 108. Image CODEC
At 104, when image data is input, it is decoded and D
The A / A converter 109 converts the analog image signal and displays it on the display 110. In addition, when voice data is input to the voice CODEC 108, the voice data is decoded and converted into an analog voice signal by the D / A converter 107, and the handset 1
Output to the speaker of 05.

In the apparatus according to the first embodiment of the present invention, when the image CODEC 104 encodes the digital image data output from the A / D converter 103, the encoding speed of the central portion of the image is set to the peripheral portion of the image. By making it relatively fast with respect to the part, the quality of the central part of the image can be improved. As a method of realizing this, for example, the resolution of the image is increased in the central portion of the image and decreased in the peripheral portion, or the number of frames in the central portion of the image is increased so that the image moves smoothly. , Etc. are encoded.

FIG. 2 is a block diagram showing an example of the internal structure of the image CODEC 104. In the figure, 10
Reference numeral 41 denotes an image identification separation unit that identifies and separates an area to be encoded with high quality and an area to be encoded with relatively low quality from an input digital image, and 1042 converts the resolution of the image from high resolution to low resolution. A resolution conversion unit 1043, a memory (1) for temporarily storing image data to be encoded with high quality, a memory (2) for temporarily storing image data to be encoded with low quality, and a memory (1 ) 1
043 and a coding unit for reading and compressing and coding the image data stored in the memory (2) 1044, and 1046 for a decoding unit for decoding the received and compression-coded image.
Reference numeral 47 is a timer (1), 104 for counting a time interval for encoding the image data stored in the memory (1) 1043.
Reference numeral 8 denotes a timer (2) for counting the time interval for encoding the image data stored in the memory (2) 1044, 1049
Is a buffer memory for accumulating the image data previously encoded.

Image CODEC having the configuration shown in FIG.
In (104), the digital image data output from the A / D converter 103 is input to the image identification / separation unit 1041, where the image data is encoded in a high-quality area (hereinafter referred to as the image area ( Data belonging to 1)),
Area to be encoded in low quality (hereinafter referred to as image area (2)
The image data in the image area (1) is output to the memory (1) 1043, and the image data in the image area (2) is output to the resolution conversion unit 1042. Then, the image data of the image area (2) is converted into a low-resolution image by the resolution conversion unit 1042 and output to the memory (2) 1044.

The image CODEC 104 shown in FIG.
Then, encoding is performed so that the image data is updated at equal time intervals so that the number of frames per time is always constant. Then, by changing the time interval for updating the image data in the central portion and the peripheral portion of the image, for example, the image is made to move smoothly in the central portion of the image compared to the peripheral portion. A timer (1) 1047 and a timer (2) 1048 are connected to the encoding unit 1045, and these perform counting operation according to an instruction from the encoding unit 1045. Then, when each timer performs counting operation for a predetermined time, it transmits a signal indicating the end of counting to the encoding unit 1045. When the encoding unit 1045 detects the count end signal from the timer (1) 1047, the memory (1) 1043
When the image data of the image area (1) stored in the memory is read out, compression-encoded and output to the system control unit 101, and when the count end signal from the timer (2) 1048 is detected, the memory (2) 1044 stores it. The accumulated image data of the image area (2) is read out, compression-encoded, and output to the system control unit 101.

The setting range of the image area (1) and the image area (2) may be set as shown in FIG. 3, for example. FIG.
In the figure, 301 indicates an image of one frame, and 3
Reference numeral 02 denotes an image area (1) for performing high-quality image encoding, 30
Reference numeral 3 is an image area (2) in which low quality image encoding is performed.
Usually, when communicating with a partner through a TV phone, the figure or face of the partner is reflected in the center of the image, and the peripheral area of the image is often the background. Further, when the user on the receiving side views the transmitted image through the display 110, he pays attention to the central portion of the image rather than the peripheral portion. Therefore, as shown in FIG. 3, image area (1) 302
Is set in the center of the image, and the other area is set in advance in the image area (2) 303. As for the setting information of the image area (1), for example, as shown in FIG. 3, an image of one frame is regarded as a collection of data given by the coordinates of two axes of (X, Y), and (X1, Y1) and ( X2, Y
It may be assumed that it is a rectangle defined by the two points of 2).

When the image data digitized by the A / D converter 103 is input, the image identification / separation unit 1041 receives the image data of the image area (1) or the image area (2) of the individual data. Image data is identified and output to the memory (1) 1043 or the resolution conversion unit 1042.

The above-described image area identification and separation processing is performed, for example, by the sequence shown in FIG. When the image data is input to the image identification separation unit 1041 (step S401), it is determined whether the coordinates (Xd, Yd) of the input individual image data are within the range of the area (1) (S402). If it is within the range of the image area (1), the image data is output to the memory (1) 1043 (step S403). If it is not within the range of the image area (1), the image data is stored. It is output to the resolution conversion unit 1042 (step S404).

The output of the image data to the memory (1) 1043 or the resolution converter 1042 is performed in synchronization with the operation of the timer (1) 1047 or the timer (2) 1048, respectively. That is, the timer (1) 104
When 7 ends the counting operation and outputs a signal indicating the end of counting, the image identification separation unit 1041 separates the image data of the image area (1) from the frame image input immediately after the detection of this signal. And outputs it to the memory (1) 1043. When the timer (2) 1048 finishes the counting operation and outputs a signal indicating the end of counting, the image identification separation unit 1
041 separates the image data of the image area (2) from the frame image input immediately after detecting this signal, and outputs it to the resolution conversion unit 1042.

The resolution conversion unit 1042 converts the image data of the image area (2) into a resolution lower than the image resolution sampled by the A / D converter 103 to reduce the number of pixels, that is, the amount of image data. Later, it outputs to the memory (2) 1044.

For resolution conversion, for example, as shown in FIG. 5, one specific pixel 501 out of four adjacent pixels is regarded as a representative pixel, and all other pixels may be replaced with the pixel 501. As a result, the data amount for four pixels can be reduced to the data amount for one pixel. In the example of FIG. 5, the vertical and horizontal two pixels (four pixels in total) are replaced with the upper left pixel, but it goes without saying that the number of pixels and the position of the representative pixel may be those other than FIG. In addition to this, for example, the average value of the levels of the pixels may be used as the representative pixel.

As a result, the image data amount per fixed area is smaller in the image region (2) than in the image region (1), the image data amount of the entire frame is reduced, and the image quality is The image area (1) is relatively better than the image area (2).

Further, in the image area (2), in addition to lowering the resolution, for example, the number of bits expressing the gradation level of each pixel is made smaller than that in the image area (1), thereby reducing the image data amount. You may make it reduce. Alternatively, in the case where each area is divided into a plurality of fine blocks in encoding and the DCT coefficient is obtained in each block, the quantization width of the coefficient of the image area (2) is increased to increase the coefficient of high order. By making it easily 0, the output code amount may be reduced, while the coefficient quantization width may be reduced in the image region (1) to reduce image deterioration.

The timer (1) 1047 and the timer (2) 1048 perform initialization such as setting of counting time according to an instruction from the encoding unit 1045, and
Starts and stops the counting operation. Then, when each of the timers 1047 and 1048 starts the counting operation and counts for the set time, it outputs a signal indicating that the counting operation is completed to the encoding unit 1045.

FIG. 6 is a sequence diagram showing a procedure for encoding each image data of the image area (1) and the image area (2) by the encoding unit 1045.

The encoding unit 1045 first initializes the timer (1) 1047 and the timer (2) 1048, sets the counting time of each timer, and then starts the counting operation of each timer (step S60).
1). Then, the encoding unit 1045 uses the timer (1) 1
It is monitored whether or not 047 or the timer (2) 1048 outputs a signal indicating the end of the counting operation (steps S602 and S603).

If YES is determined in step S602 (when the counting operation end signal of the timer (1) 1047 is detected), the initialization of the timer (1) 1047 and the start of the re-counting operation are instructed (step S60).
4) Waiting for the image data of the image area (1) to be output to the memory (1) 1043 from the image identification separation unit 1041, and then the encoding unit 1045 causes the memory (1) 104
The image data of the image area (1) stored in the image area 3 is read (step S605), and the image data of the image area (1) is compression-encoded (step S606). And
The encoded data is output to the communication control unit 112 via the system control unit 101 (step S607).

If YES is determined in step S603 (when the counting operation end signal of the timer (2) 1048 is detected), the encoding unit 1045 initializes the timer (2) 1048 and starts the re-counting operation. The resolution conversion unit 104 is instructed (step S608).
2 is waited for the image data of the image area (2) whose resolution has been converted from 2 to be output to the memory (2) 1044, and then the encoding unit 1045 causes the image area (2) stored in the memory (2) 1048. ) Is read (step S609), and the image data of the image area (2) is compression-encoded (step S610). Then, the encoded data is transmitted to the communication control unit 11 via the system control unit 101.
2 (step S611).

At this time, the time interval counted by the timer (1) 1047, that is, the time interval for updating the image data of the image area (1) (this is referred to as t1) is the time interval counted by the timer (2) 1048. That is, t1 <t2 is set with respect to the time interval for updating the image data of the image area (2) (this is referred to as t2). As a result, in the image to be transmitted, the image data of the image area (1) is updated at a shorter time interval than the image area (2), so that the image quality of the image area (1) is compared with that of the image area (2). And you can make it relatively better.

The coding unit 1045 monitors the code amount generated by the coding, and adjusts the code amount so that this amount does not exceed the data amount M that can be transmitted in a predetermined time on the communication line 114. To do. The code amount can be adjusted, for example, in encoding by encoding only an area where the image changes to some extent compared to the previous image, and an area where the change is small with respect to the previous image is the image transmitted in the previous encoding. To be displayed continuously. This can be realized, for example, as follows.

In the image coding, the image area is divided into a plurality of blocks each having several tens of pixels (for example, 8 × 8 pixels), and the image data is coded for each block.
The encoded image data is transmitted. At this time, the encoded image data is stored in the buffer memory 1049. Then, when new image data is encoded according to the instruction of the timer (1) 1047 or the timer (2) 1048, the previous image data and the current image data are compared for each block, and the previous image data is compared. Image of the block is continuously used, or the image of the block is newly encoded.

FIG. 7 is a sequence diagram showing an encoding procedure for each individual block. The encoding unit 1045 detects the amount of change between the previous image stored in the buffer memory 1049 and the new image to be encoded for each block (step S701). Then, it is determined whether or not the change amount is larger than a predetermined threshold value n (step S702), and if the change amount is larger than the threshold value n, the image data of the block is encoded (step S703). ), The amount of change is the threshold value n
In the case of the following, a code indicating that the previous image is continuously used as a new image (hereinafter referred to as a continuation code) is output (step S704).

When the coding is performed for each block in this way, the coding unit 1045 calculates the total sum of the output code amounts. Then, the code amount is adjusted in the sequence shown in FIG.

If the sum of the code amounts is equal to or less than the predetermined amount M, the encoding unit 1045 will output the output code to the communication control unit 112.
(YES is determined in step S801, and the processing sequence ends). If the sum of the code amounts is larger than M in step S801 (step S80
If NO in 1), the encoding unit 104
In block 5, the block in which the continuation code is not output in the encoding, that is, the block in which the image data in the block is encoded and output is searched for the block having the smallest change amount (step S802), and the block of the block is searched. The code is replaced with the continuous code from the code of the image data (step S803). By replacing the code of the image data with the continuous code, the code amount of the block can be reduced. After that, the encoding unit 1045 again compares the total sum of the code amounts with the predetermined amount M (step S801). Here, when the sum of the code amounts is larger than the predetermined amount M,
The processes of steps S802 and S803 are performed again, and this is repeated until the sum of the code amounts becomes equal to or less than the predetermined amount M, and the code generated in this way is output to the communication control unit 112.

After that, the encoding unit 1045 updates the image data stored in the buffer memory 1049. For a block for which a code indicating continuous use is not used in encoding, the previous image data in the block is erased, new image data is stored in the buffer memory 1049, and the code indicating continuous use is used. This is because the previous image data of the existing block is retained in the buffer memory 1049.

The method of detecting the amount of change in the image in the block is as follows:
For example, for each pixel in the block, it is possible to compare whether the levels of the previous image data and the new image data match, and use the number of pixels that do not match as the amount of change. Alternatively, for each pixel, the absolute error of the level between the previous image data and the new image data may be calculated, and the sum of the absolute errors within the block may be used as the change amount. The threshold value n may be different between the image area (1) and the image area (2). For example, the threshold value of the image area (1) is n1, the image area (2) is If the threshold of is n2, then n1 <n2 may be satisfied.
As a result, in the block in the image area (1), even if the change amount is smaller than that in the block in the image area (2),
Since the image data is encoded and the image data is updated, the quality of the image can be improved as compared with the image area (2). Further, by setting the value of the threshold value n2 to be larger than n1 in the image area (2), the continuous code is more easily output in the encoding than the image area (1).
It is possible to reduce the output image code amount.

By the way, in the apparatus according to the first embodiment shown in FIG. 1, the size and position of the image area of high quality in the image to be transmitted are set in advance, and the size and position are set from the receiver side. It cannot be changed. Therefore, if the image of interest to the recipient is in the periphery of the image, a good image cannot be obtained. Therefore, a setting unit that sets the range and the number of frames of the image area (1) on the terminal device side that receives the image and a communication function that communicates information about the set image area and the like to the terminal device side that sends the image are provided. By providing the terminal device side that transmits the image with the function of detecting the setting information and changing the encoding procedure of the image CODEC according to the setting content, the receiver can receive the received image of the received image. It is possible to make an arbitrary region a high quality image.

FIG. 9 is a block diagram showing the configuration of the terminal device in the videophone system according to the second embodiment of the present invention having such a function.

In the terminal device according to the second embodiment of the present invention shown in FIG. 9, in addition to the configuration of the terminal device of the first embodiment described above, operations such as setting a high quality image area and adjusting image quality are performed. And an image setting unit 116 for transmitting setting information to the system control unit 101. Also, the communication control unit 11
In 2, the setting information set by the image setting unit 116 is transmitted to the partner terminal and the image setting information transmitted from the partner terminal device to the present device is detected. Also, the image CO
The encoding unit 1045 of the DEC 104 changes the encoding procedure according to the image setting information from the partner terminal device, changes the size and position of the image area (1) described above, and sets the time interval for encoding the image data. Change it. As a result, in the terminal device according to the second embodiment, both communicating users can improve the quality of the desired area of the received image.

FIG. 10 is a view showing an example of the operation panel of the image setting section 116. In the example shown in FIG. 10, the operation panel has four buttons 1001, 1002, 1003.
1004 is provided. For each button, the setting values of the coordinates (X1, Y1) and (X2, Y2) forming the image area (1) 302 in FIG. 3 are set in the upward direction by the button 1001, the left direction by the button 1002 and the left button by the button 1003. The button 1004 directs a downward movement and a rightward movement by a predetermined amount.

FIG. 11 is a sequence diagram showing a process when any of the buttons 1001 to 1004 is pressed.
The system control unit 101 monitors whether any of the buttons 1001 to 1004 has been pressed (step S
1101, S1102, S1103, S1104), when any button is pressed, the coordinates (X1, Y1) and (X2, Y) forming the image area (1) are correspondingly pressed.
2) is moved by a predetermined amount a (step S1105,
S1106, S1107, S1108).

When the user changes the setting of the image area (1) as described above by pressing the button,
The display may be performed via the display 110 so that the user can know that the change has been made.

FIG. 12 is a view showing an example of image display when the position of the image area (1) is set, and 1201
Is a display screen of the display 110, and 1202 is an image area (1)
It is a gauge line showing the range of. The gauge line 1202 is displayed by being combined with the received image and indicates where the image area (1) is located with respect to all the images. Gauge wire 1202
The display operation of is, for example, four buttons 1 in FIG.
After any one of 001 to 1004 is pressed and the corresponding processing (step S1105, S1106, S1107 or S1108) is performed, the gauge line 1202 is displayed for a certain period at the position of the newly set image area (1). Just do it.

When the position of the image area (1) is set according to the procedure shown in FIG.
The position setting information is transmitted to the partner terminal device via 12 and the line 1 / F113. As a communication method, for example, a packet is used for transmission of various data, and a packet indicating image setting information is prepared in addition to a packet for image data, audio data and communication control data, or a packet for communication control data A packet indicating the image setting information is prepared in, for example, and the information of the coordinates forming the image area (1) is put on the packet for communication.

FIG. 13 is a diagram showing an example of such a packet. FIG. 13A shows a packet used for communication of communication control data, and FIG. 13B shows image data communication. The packets used are shown in FIG. 13C, which are used for voice data communication. In the packet example shown in FIG. 13, the HDLC procedure (High lev
The packet structure conforming to the el DataLink Control Procedure) is used, and the image setting data is stored in the communication control packet.

In FIG. 13, reference numeral 1301 is a flag for synchronizing packets in communication, 1302 is packet address information, 1303 is control command information indicating the type of packet, and 1304 is the device shown in FIG. 1 or 9. Communication control data 1305 indicating data such as a communication method between terminals, terminal functions and data format
Is image setting data indicating image setting information, and 1306 is an FCC (Frame Check Cod) for checking a packet error.
e) and 1307 are image identification information indicating that the packet of FIG. 13B is a packet for storing image data,
Reference numeral 1308 is image data, 1309 is voice identification information indicating that the packet in FIG. 13C is a packet storing voice data, and 1310 is voice data. FCC
1306 includes, for example, parity and CRC (Cyclic Redun).
dancy Code) is used. In addition, the image setting data 13
As shown in FIG. 14, for example, 05 is image setting identification information 1401 for identifying that the following information is image setting data, information 1402 of coordinates (X1, Y1) of the image area (1), and image area. A format such as the information 1403 of the coordinates (X2, Y2) in (1) may be used.

The communication control unit 112 assembles packets as shown in FIG. 13 and exchanges image data 1308, audio data 1310, and communication control data 13 with the partner terminal.
04, and control data such as the image setting data 1305. When the partner terminal device receives these packets, the communication control unit 112 causes the control command information 130.
3, by image identification information 1307 and voice identification information 1309, it is separated into image data, voice data, and control data,
The image data is sent to the image CODEC 104, and the audio data is sent to the audio CODEC 108. Further, when the communication control unit 112 detects the image setting data 1305 from the data in the packet of FIG. 13A, it sends it to the image CODEC 104 via the system control unit 101.

When the image CODEC 104 receives the image setting data 1305 from the partner terminal, the information 1402 (X1, Y1) 1402 and (X1) of the image area (1) are received from the image setting data 1305.
(2, Y2) information 1403 is read, and the set values of (X1, Y1) and (X2, Y2) set by the image identification separation unit 1041 are updated to new values. If the image area (1) or the image area (2) is in the process of being encoded in the updating of the set value, after the encoding of the area is completed, (X1, Y1)
And the set values of (X2, Y2) are updated to new values. As a result, the A / D converter 10 receives an instruction from the next timer (1) 1047 or timer (2) 1048.
When the image area (1) or the image area (2) is identified and separated from the image data input from 3, the identification and separation processing is performed according to the newly set coordinates.

Thus, the user receiving the image can view the received image by making the newly set area a high quality image. Further, by operating the buttons 1001 to 1004 shown in FIG. 10 even during communication, it is possible to set an area of the received image to be a high quality image.

FIG. 15 is a view showing another example of the operation panel of the image setting section 116. In the example shown in FIG. 15, on the operation panel, in addition to the four buttons 1001, 1002, 1003, 1004 shown in FIG. 10, a button 15 for entering a mode for setting the position of the image area (1) is displayed.
01, a button 1502 for entering a mode for changing the range of the image area (1), and a button 1503 for entering a mode for changing the update time interval of the image data of the image area (1) are provided. As a result, in the present example shown in FIG. 15, the receiver side can set the size of the image area (1) and the number of frames in addition to the position setting of the image area (1). ing. Image settings are button 1501, button 15
The operation is started by pressing any of 02 and button 1503. When the button 1501 is pressed, the button 10
The position is set by operating 01 to 1004.
When the button 1502 is pressed, the range of the image area (1) is increased by pressing the button 1001 and the range of the image area (1) is decreased by pressing the button 1003. When the button 1503 is pressed, the button 10
Pressing 01 shortens the time interval for updating the image in the image area (1), and pressing the button 1003 lengthens the time interval for updating the image in the image area (1).

When the setting of the image area (1) is changed as described above, the display may be performed via the display 110 so that the user can recognize the change. For example, the position setting and the range setting are displayed by the gauge line 1202 shown in FIG. 12, and the display method of the gauge line 1202 is, for example, the button 1501 or the button 1502.
When is pressed, (X1, Y1), (X2, Y at that time
The gauge line 1202 is displayed according to the setting value of 2), any of the four buttons 1001 to 1004 is pressed, and (X
When the values of (1, Y1) and (X2, Y2) are changed, the gauge line 1202 is displayed according to the changed value. Then, when there is no input for a certain period of time, the display of the gauge line 1202 is stopped, and the setting value at that time is transmitted to the partner terminal as image setting information.

Further, the setting of the image update speed is performed, for example, by
When the button 1503 is pressed, the set value of the time interval at that time is displayed by combining the level bar 1601 and the level gauge 1602 as shown in FIG. 16 with the received image to display the level gauge button 1001 or the button 1003. When the value of the time interval is changed by, the level gauge 1602 is displayed according to the changed value. Then, when there is no input for a certain period of time, the display of the level bar 1601 and the level gauge 1602 is stopped, and the set value at that time is transmitted to the partner terminal as image setting information.

When the image setting is performed, the system control unit 101 transmits the position setting information to the partner terminal device via the communication control unit 112 and the line I / F 113. As the communication method, for example, a packet as shown in FIG. 13 may be used. In this case, the image setting data 1305 stores the position information of the image area (1) and the update time interval of the image data of the image area (1).

Upon receiving the image setting data 1305, the partner terminal sends it to the image CODEC 104. When the image CODEC 104 receives the image setting data 1305, the information 1402 of (X1, Y1) and the information 1403 of (X2, Y2) of the image area (1) are read from the image setting data 1305 and set by the image identification separating unit 1041. (X1, Y1)
And the set values of (X2, Y2) are updated to new values. Also, the data of the update time interval of the image data of the image area (1) is read, and the counting time of the timer (1) 1047 is set. As a result, the user receiving the image receives the buttons 1001 to 1004, 150 shown in FIG. 15 even during communication.
By performing operations 1 to 1503, it is possible to set the position, size, and number of frames of a region to be a high quality image.

The image setting procedure in the image setting section 116 is as follows.
Instead of the method shown in FIG. 10 or 15, a pointing device such as a touch panel or a mouse may be used. For example, in the case of using a touch panel, the display unit 110 is provided with a detection unit that detects that a finger or the like has come into contact with the system control unit 101, and notifies the system control unit 101 which position on the screen the user has touched. While looking at the received image displayed on, touch the part of the image you want to display in high quality,
The range of the image area (1) may be set by the system control unit 101 so that the image has high quality centered on the touched position. Further, in the case of using a mouse, for example, when a drag operation is performed, the system control unit 101 detects this, and the rectangular area set by the drag operation is displayed on the other terminal as image setting information of the image area (1). You may tell it.

[0061]

As described above, according to the present invention, in image coding, by making the coding speed of a specific area faster than other areas, it is possible to improve the image quality of the area. it can. Further, by controlling the image coding procedure from the receiving terminal side to the transmitting terminal side, the user who receives the image can specify the area to be a high quality image. As a result, even when image transmission is performed through a communication line with a low transmission rate, the image of interest on the receiving user side can be of high quality, and the image desired by the user who receives the image can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a terminal device in a videophone system according to a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of an image CODEC 104 of FIG.

FIG. 3 is an explanatory diagram showing an example of an image area (1) and an image area (2) in the first embodiment example of the present invention.

FIG. 4 is a sequence diagram showing an operation of an image identification separation unit 1041 in the first embodiment example of the present invention.

FIG. 5 is an explanatory diagram showing an example of resolution conversion processing of a resolution conversion unit 1042 according to the first exemplary embodiment of the present invention.

FIG. 6 is a sequence diagram showing an encoding operation of the encoding unit 1045 in the first embodiment example of the present invention.

FIG. 7 is a sequence diagram showing an encoding procedure for each individual block in the first embodiment example of the present invention.

FIG. 8 is a sequence diagram showing a procedure for adjusting the code amount in the first embodiment example of the present invention.

FIG. 9 is a block diagram showing a configuration of a terminal device in the videophone system according to the second embodiment of the present invention.

FIG. 10 is an explanatory diagram showing an example of button arrangement on the operation panel of the image setting unit 116 in FIG.

FIG. 11 is a sequence diagram showing an operation of the image setting unit 116 in the second embodiment example of the present invention.

FIG. 12 is an explanatory diagram showing an example of a screen display at the time of setting by the image setting unit 116 in the second embodiment example of the present invention.

FIG. 13 is an explanatory diagram showing an example of the configuration of a packet used in a communication sequence in the second embodiment example of the present invention.

14 is an explanatory diagram showing an example of the configuration of image setting data 1305 in the packet shown in FIG.

15 is an explanatory diagram showing another example of button arrangement on the operation panel of the image setting section 116 of FIG.

FIG. 16 is an explanatory diagram showing another example of the screen display at the time of setting of the image setting unit 116 in the second embodiment example of the present invention.

[Explanation of symbols]

 101 system control unit 102 camera 103 A / D converter 104 image CODEC 1041 image identification separation unit 1042 resolution conversion unit 1043 memory (1) 1044 memory (2) 1045 encoding unit 1046 decoding unit 1047 timer (1) 1048 timer ( 2) 1049 buffer memory 105 handset 106 A / D converter 107 D / A converter 108 voice CODEC 109 D / A converter 110 display unit 111 operation unit 112 communication control unit 113 line interface (line I / F) 114 communication line 115 memory 116 image setting unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Tanaka 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture Hitachi, Ltd. Multimedia System Development Division

Claims (7)

[Claims] 1. An image transmitting apparatus having a function of transmitting a moving image or a still image, comprising: an image separating means for separating an input image signal into a plurality of areas; and an encoding means for compressing and encoding an image. An image signal to be transmitted is divided into a plurality of image areas by the image separating means, and each image area separated by the encoding means is encoded at a different encoding speed. Image transmission device. 2. An image transmission device having a function of transmitting a moving image or a still image, wherein a first image region for transmitting an input image signal to a partner terminal device with a first image quality, and the first image region. A second image area that is an area other than the area and that has a second image quality different from that of the first image area and that is identified and separated by an image identification and separation unit that identifies and separates the image resolution. Resolution conversion means for converting the resolution to a resolution lower than the original resolution, and the image signal to be transmitted is separated into the first image area and the second image area by the image identification separation means, The image in the second image area is converted into a low-resolution image by the resolution conversion means and then encoded to obtain the first image.
The image transmission apparatus characterized in that the encoding speed of the first image area and the second image area is changed by directly encoding the image of the image area. 3. An image transmission apparatus having a function of transmitting a moving image or a still image, a first image area for transmitting an input image signal to a partner terminal device with a first image quality, and the first image area. An image identifying and separating unit that identifies and separates into a second image region that is a region other than the region and that is transmitted to the partner terminal device with a second image quality different from the first image region; Time interval t1 for encoding the image area
And a time interval t2 for encoding the second image area.
And a second counting means for counting the image signal to be transmitted, the image signal to be transmitted is separated into the first image area and the second image area by the image identifying and separating means, and the image coding of each area is performed. The image transmission apparatus is characterized in that encoding is performed such that a time interval for performing the above is t1 ≠ t2. 4. The method according to claim 1, 2 or 3, wherein DCT encoding is performed when an image is encoded.
An image transmission apparatus comprising: the encoding means, and performing encoding at a different encoding speed for each image area by changing the quantization width of the DCT coefficient to be encoded for each image area. 5. The method according to claim 1, 2 or 3, further comprising: second encoding means for quantizing the original data to encode the image when encoding the image, and quantizing each image area. An image transmission device characterized by performing encoding at a different encoding speed for each image area by changing the number of bits. 6. The first instruction means for setting the range of the first image area in the terminal device on the image receiving side according to any one of claims 2 to 5, and the first instruction. Communication means for communicating the range setting information set by the means to the terminal device on the image transmitting side, and the user on the receiving side uses the first instructing means for the first
When the range of the image area is set, the communication means communicates the range setting information of the first image area to the terminal device on the image transmitting side, and the terminal device on the image transmitting side communicates the image identifying and separating means according to the range setting information. The image transmission device is characterized in that the image area desired by the user on the receiving side is made high in quality by controlling the. 7. The second instruction means for setting a time interval for updating the image of the first image area, in the terminal device on the image receiving side according to claim 3, 4, or 5, Communication means for communicating the setting information of the update time interval set by the instructing means to the terminal device on the image transmitting side, and the user on the receiving side by the second instructing means.
When the update time interval of the image area is set, the communication means communicates the setting information of the update time interval of the first image area to the terminal device on the image transmitting side, and the terminal device on the image transmitting side indicates the update time interval. An image transmission apparatus, characterized in that the first image area is received by the number of frames desired by a user on the receiving side by controlling the first counting means in accordance with setting information.