JPH0984003A - Image data communication method and image data communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce an image with high recognition degree without deteriorating a transmission efficiency by improving a transmission error correction capability with respect to an important contour to recognize an image in the case of sending a still image. SOLUTION: An image to be sent is divided into coded blocks at a transmitter side and whether or not a contour is included in each coded block is discriminated (14). A discrimination image is discriminated (41) and error correction coding (4) with a high error correction capability is applied to image data after compression coding (3) to a coded block including the contour. Error correction coding (4) with a low error correction capability is applied to image data after compression coding (3) to a coding block not including the contour and the resulting data are transmitted (5). A receiver side applies error correction decoding (8) to the received data and expansion decoding (9) to reproduce an image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image data communication method and an image data communication device used for transmitting a still image, and particularly to a contour portion important for recognizing an image without lowering transmission efficiency. The present invention relates to an image data communication method and an image data communication device capable of reproducing a highly recognized image with improved transmission error correction capability.

[0002]

2. Description of the Related Art First, a conventional image data communication device will be described with reference to FIG. FIG. 7 is a configuration block diagram of a conventional image data communication device. In the conventional image data communication apparatus, as shown in FIG.
An image input unit 2 ', a compression encoding unit 3', an error correction encoding unit 4 ', and a communication control unit 5, and the receiving side includes a communication control unit 7 and an error correction decoding unit 8 ′, Decompression decoding unit 9, image output unit 10 ′, and reproduced image storage unit 11
The transmission side and the reception side are connected via a transmission line 6.

Next, each part of the conventional image data communication device will be described. The original image storage unit 1 is a storage unit that stores image data of an image (original image) for one screen to be transmitted. The image input unit 2 ′ sequentially reads the image data of the unit (encoding block) to be compression-encoded from the original image storage unit 1 and outputs the image data to the compression-encoding unit 3 ′.

The compression encoding unit 3'compresses the image data of the original image in units of encoding blocks and outputs the compressed image data. An example of the compression encoding method is JP
The EG (Joint Photographic Experts Group) method is generally used.

Here, the JPEG system will be briefly described. In the JPEG method, an original image is encoded block of, for example, 8 pixels × 8 pixels, that is, an MCU (Minimum Code Uni
It is divided into blocks and divided into encoded blocks (M
DCT (Discreat Cosine Transform) conversion in CU units, quantization using a quantization table, and information source coding (compression coding) by entropy coding using a coding table are performed to perform compression in MCU units. Create image data.

On the receiving side, entropy decoding using the same coding table as the information source coding performed on the transmitting side, dequantization using a quantization table, and inverse DCT are performed.
Information source decoding in MCU units by conversion (decompression decoding)
To play the image.

The error correction coding unit 4'adds an error correction code for detecting and correcting a transmission error to the compressed image data of the MCU unit output from the compression coding unit 3 '. The data is encoded and the encoded data is output.

Here, as an example of error correction coding, one that only performs error detection, one that also performs correction after error detection, one that has a high or low error correction capability, and an error that is independently and randomly There are various types of error correction codes, such as one corresponding to a random error that occurs and one corresponding to a burst error in which errors continuously occur.

Generally, an error correction code is used only for error detection.
Alternatively, a code having a low error correction capability has a high coding rate and a short code length, and a code having a high correction capability tends to have a low coding rate and a long code length. Therefore, the conventional image data communication device does not unconditionally adopt an error correction code having a high error correction capability, but adopts an error correction code suitable for the communication system in consideration of the quality and characteristics of the transmission line 6. It was normal.

As an example of an error correction code for performing only error detection, CRC (Cyclic Redundancy Check) which is known to be able to detect both random error and burst error
s) There is a code, and details are “Computer communication and networks” by Kunio Fukunaga, Kyoritsu Publishing Co., Ltd. p78-p82
It is described in. Also, as an example of the error correction code,
BCH code (Bose-Chaud) is used as a code with high error correction capability.
huri-Hocquenghem Code) is known, and details are described in "Information and Coding Theory" Kiyoshi Hashimoto Morikita Publishing Co., Ltd. p10
1 to p104 are also described. Other various error correction codes are also introduced in "Image Band Compression and Coding Technology" by Yuichi Ninomiya, Nikkan Kogyo Shimbun, Ltd., p125-p141.

The communication control section 5 modulates the coded data in MCU units output from the error correction coding section 4'to a signal suitable for the transmission path 6 and sends it to the transmission path 6. Further, the communication control unit 7 demodulates the data received from the transmission path 6 and outputs the encoded data to the error correction decoding unit 8 '.

The error correction decoding unit 8'detects an error from the error correction code of the encoded data received from the communication control unit 7, corrects the error if correctable, and corrects the error-free data and the error. The corrected data is output to the decompression decoding unit 9 as normal reception data. On the other hand, data that cannot be error-corrected is discarded.

The decompression decoding unit 9 includes an error correction decoding unit 8 '.
The image data is output by decompressing and decoding the normally received data received from, and the reverse of the compression encoding performed by the compression encoding unit 3'is performed.

The image output unit 10 'sequentially stores the image data received from the decompression decoding unit 9 in the reproduced image storage unit 11. The reproduction image storage unit 11 is a storage unit that stores the image data of the transmitted and decoded reproduction image.

Next, the operation of the conventional image data communication device will be described with reference to FIG. In the conventional image data communication device, the image input unit 2 ′ reads the image data of the original image stored in the original image storage unit 1 in units of MCU,
The data is compression-encoded by the compression encoder 3 ', error-correction encoded by the error-correction encoder 4', modulated by the communication controller 5 and sent to the transmission line 6.

On the receiving side, the data received from the transmission path 6 is demodulated by the communication control unit 7 and error-correction decoded by the error-correction decoding unit 8 ', and uncorrectable data is discarded.
Only the normally received data is decompressed and decoded by the decompression decoding unit 9 and stored in the reproduced image storage unit 11 by the image output unit 10 'so that the reproduced image data for one screen is stored in the reproduced image storage unit 11. It has become.

[0017]

However, in the above-mentioned conventional image data communication method and image data communication device,
The error correction coding unit 4'and the error correction decoding unit 8'use a single error correction code, and when adopting the error correction code, the characteristics of the image data are considered even if the characteristics of the communication system are considered. However, there is a problem that if the transmission efficiency is emphasized, the error correction capability is lowered and the quality of the reproduced image is lowered, and if the error correction capability is emphasized, the transmission efficiency is lowered.

Generally, the human eye is more sensitive to the noise in the flat portion than in the contour portion, so that the noise generated in the flat portion may cause a remarkable deterioration in image quality. However, on the other hand, the information of the contour portion is important for recognizing the contents of the image. That is, since humans recognize image information by observing a two-dimensional structure composed of the contour portion, even if the flat portion of the image is deteriorated, if the contour remains, the information (image content and characteristics of the image) ) Can be transmitted.

The present invention has been made in view of the above circumstances, and an image data communication method and an image data communication method capable of improving the recognition degree of a reproduced image without lowering the overall transmission efficiency in consideration of the characteristics of the image data. An object is to provide a data communication device.

[0020]

The invention according to claim 1 for solving the problems of the above-mentioned conventional example is to divide an image to be transmitted on the transmission side into coding blocks, perform compression coding, and further perform error correction coding. And transmit it, and the error correction decoding is performed on the receiving side,
In an image data communication method of decompressing and decoding and reproducing an image, it is determined whether or not a contour is included in each of the coding blocks, the determination result is determined, and a compression code is applied to a coding block including a contour. The image data after encoding is subjected to error correction coding with high error correction ability, and the image data after compression encoding is subjected to error correction encoding with low error correction ability for the coding block that does not include the contour. The feature is that data is transmitted, and the error correction capability of the contour portion can be enhanced without lowering the overall transmission efficiency.

The invention according to claim 2 for solving the problem of the above-mentioned conventional example is performed by receiving data transmitted by the image data communication method according to claim 1 and transmitting the received data on the transmitting side. Error correction coding is discriminated, and based on the discrimination result, the received data is subjected to error correction decoding corresponding to the error correction coding made on the transmitting side, decompression decoding is performed, and further error correction is impossible. Since the existing data is interpolated, high-level error correction is performed on the contour part, low-level error correction is performed on the part that does not include the contour, and interpolation is performed on the uncorrectable part. High-quality images can be reproduced.

According to a third aspect of the present invention for solving the problems of the conventional example, the transmitting side compresses and encodes image data in units of encoded blocks, and an error correction is performed on the compressed image data. In an image data communication device having an error correction coding unit for coding and transmitting, a contour judgment unit for judging whether or not the coding block includes a contour is provided, and the error correction coding unit is arranged to perform the contour judgment. Error correction coding with high error correction capability when the contour is included, and error correction coding with low error correction capability is performed when the contour is not included. Since it is characterized by being a part, it is possible to enhance the error correction capability of the contour portion without lowering the overall transmission efficiency.

According to a fourth aspect of the present invention for solving the problems of the conventional example, the receiving side receives the transmission data transmitted from the image data communication apparatus according to the third aspect and performs error correction. In an image data communication device having a decoding unit and a decompression decoding unit for decompressing the corrected image data, the error correction decoding unit discriminates error correction coding performed on the transmission side for received data. Then
An error correction decoding unit that performs error correction decoding corresponding to the error correction coding performed on the transmission side on the basis of the determination result, and for the image data that cannot be error corrected. It is characterized by the provision of an interpolation unit that performs interpolation, so that the contour part performs high-level error correction, the part that does not include the contour performs low-level error correction, and the uncorrectable part interpolates It is possible to reproduce high-quality images.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the claimed invention will be described with reference to the drawings. The image data communication method according to the present invention discriminates whether or not the contour of the image is included for each MCU, and an error correction code having a low coding rate but high error correction capability is used for the MCU including the contour, For an MCU that does not include a contour, error correction coding and decoding are performed using an error correction code that has a low error correction capability but a high coding rate. Therefore, it is possible to display an image without lowering transmission efficiency as a whole. By improving the transmission error correction capability of the contour part which is important for recognition, it is possible to reproduce a highly recognized image.

First, the configuration of the image data communication apparatus (this apparatus) according to the present invention will be described with reference to FIG. FIG.
FIG. 1 is a block diagram showing the configuration of an image data communication device according to the present invention. Parts having the same configuration as in FIG. 7 will be described with the same reference numerals.

In the present apparatus, the transmitting side has an original image storage unit 1, an image input unit 2, and a compression encoding unit 3 which are basically the same as the conventional ones.
And an error correction coding unit 4 and a communication control unit 5, and a contour value distribution extraction unit 12 as a characteristic part of the present apparatus.
A contour value distribution storage unit 13 and a contour determination unit 14 are provided.

On the receiving side, the communication control unit 7, the error correction decoding unit 8, and the decompression decoding unit 9 which are basically the same as the conventional ones are used.
And an image output unit 10 and a reproduced image storage unit 11, and an interpolation unit 15 is further provided as a characteristic part of the present apparatus. Then, the transmitting side and the receiving side are connected via the transmission line 6 as in the conventional case.

Next, each part of this apparatus will be specifically described. The original image storage unit 1 is a storage unit that stores image data of an image (original image) for one screen to be transmitted, as in the conventional case. The contour value distribution storage unit 13 is a storage unit that stores the contour value distribution of the original image stored in the original image storage unit 1.

The contour value distribution extraction unit 12 is provided in the original image storage unit 1.
The contour value distribution is extracted from the image data of the original image stored in, and stored in the contour value distribution storage unit 13, and when the extraction for one screen is completed, the input instruction is output to the image input unit 2. Specifically, a second-order differential filter S shown in FIG. 2 as an example is calculated from the pixel value distribution F (x, y) of the original image using a method such as a Laplacian operator that is generally known.
Using (i, j), the contour value distribution E (i, j) is extracted by the following equation. E (i, j) = ΣF (x + i-2, y + j-2) · S (i, j) (i, j = 0,1, ...
, 5) Incidentally, FIG. 2 shows the second derivative filter S (i, j) used in this apparatus.
It is explanatory drawing which shows the specific example of.

When the image input unit 2 receives an input instruction from the contour value distribution extraction unit 12, the unit for compression encoding (MC
U), which is, for example, 8 × 8 pixel image data, is sequentially read from the original image storage unit 1 and output to the compression encoding unit 3, and the contour value distribution of 8 × 8 pixels corresponding to the MCU is stored as a contour value distribution. It is read from the unit 13 and output to the contour determination unit 14.

The contour judging section 14 judges the contour whether the MCU coded by the compression coding section 3 contains a contour or not. Specifically, the contour value distribution of 8 × 8 pixels received from the image input unit 2 is checked, and a pixel having a large pixel value, for example, a pixel value of 200 or more is adjacent to 10 or more, a contour is included (contour is included). MCU judged as MCU and not including contour (contour-free)
And the result of the determination is output to the compression encoding unit 3.

The compression encoding unit 3 is basically the same as the conventional one, and is for performing compression encoding of the image data of the MCU unit received from the image input unit 2 and outputting the compressed image data. As a characteristic part, a 1-byte identifier indicating whether or not a contour is included is added in front of the compressed image data based on the result of determination as to whether or not the contour output from the contour determination unit 14 is added, and identifier + MCU unit The compressed image data is output to the error correction coding unit 4.

The error correction coding unit 4 performs different error correction coding on the compressed image data of the identifier + MCU unit received from the compression coding unit 3 for the contour-containing MCU and the contour-free MCU, respectively, and codes the code. The converted data is output to the communication control unit 5.

Specifically, the inside of the error correction coding unit 4 is
A discriminating means 41 for discriminating whether or not the MCU of the input compressed image data includes a contour, a contour coding means 42 for performing error correction coding for a contour-containing MCU, and a contour-free M
Non-contour coding means 43 for performing error correction coding for CU
It is composed of

Here, the discriminating means 41 is the compression encoding unit 3
It is determined whether the MCU of the compressed image data includes a contour or not by the identifier of the data received from the contour-containing MC.
In the case of U, the identifier + compressed image data is passed to the contour encoding means 42, and in the case of a contour-free MCU, the identifier + compressed image data is passed to the non-contour encoding means 43.

Further, the contour coding means 42 performs error correction coding with a high error correction capability on the identifier of the contour-containing MCU + compressed image data, and in the present apparatus, as an example, BCH (127,64). (Coding rate 0.5, maximum error correction bit number 10 bits) is used. Specifically, when the BCH (127, 64) is used, as shown in FIG. 3, the 9-byte data in which the identifier (1 byte) is added to the compressed image data (for example, 8 bytes) of one MCU is doubled. It will be encoded into a code length (18 bytes). Fig. 3 shows the BCH (127, 64) used in this device.
It is explanatory drawing which shows the example of encoding.

On the other hand, the non-contour coding means 43 performs error detection coding or error correction coding with low error correction capability only on the identifier of the non-contour-containing MCU + compressed image data. A CRC code will be used. Specifically, when a CRC code is used, as shown in FIG. 4, a 2-byte CRC code is added to 9-byte data in which an identifier (1 byte) is added to compressed image data (eg, 8 bytes) of one MCU. And is encoded into a code length of 11 bytes. FIG. 4 is an explanatory diagram showing an example of CRC encoding used in this apparatus.

As in the conventional case, the communication control unit 5 modulates the coded data of the MCU unit output from the error correction coding unit 4 into a signal suitable for the transmission line 6 and sends it to the transmission line 6. Also, the communication control unit 7 demodulates the data received from the transmission path 6 and outputs the encoded data to the error correction decoding unit 8 as in the conventional case.

The error correction decoding unit 8 performs different error correction decoding on the encoded data received from the communication control unit 7 for the encoded data of the contour-containing MCU and the encoded data of the non-contour-containing MCU. The compressed image data in the unit of MCU is output to the decompression decoding unit 9.

Specifically, the inside of the error correction decoding unit 8 is
A discriminating means 81 for discriminating whether or not the input coded data is for an MCU including a contour, a contour decoding means 82 for performing error correction decoding for a contour containing MCU, and an error correction for a contour non-containing MCU. It is composed of non-contouring decoding means 83 for performing encoding.

Here, the discriminating means 81 determines by the first 1 byte of the encoded data received from the communication control section 7 that
It is determined whether the data is the encoded data of the contour containing MCU, and in the case of the contour containing MCU, the encoded data is the contour decoding means 82.
In the case of a contour-free MCU, the encoded data is passed to the non-contour decoding means 83.

Here, the method for discriminating whether or not the encoded data of the MCU including the contour is as follows: If the first 1 byte of the encoded data coincides with the identifier indicating that the contour is not contained, the contour is not contained M
CU is discriminated. In other cases, it is discriminated as a contour containing MCU. <! ! Ask the inventor! ! > The error correction decoding unit 8 has been described so that it can be identified by whether or not the first byte is an identifier that does not include the contour.
If it is wrong, please correct it.

Further, the contour decoding means 82 performs error correction decoding with high error correction capability on the coded data of the contour containing MCU for the coding performed by the contour coding means 42 on the transmitting side, and the identifier Is removed, and the error-free data and the error-corrected data are output to the decompression decoding unit 9 as normal reception data.

On the other hand, the non-contour decoding means 83 only detects errors in the coding performed by the non-contour coding means 43 on the transmitting side, or errors with low error correction capability, with respect to the coded data of the non-contour-containing MCU. The correction decoding is performed, the identifier is further removed, and the error-free data and the error-corrected data are output to the decompression decoding unit 9 as normal reception data. On the other hand, the data in which the error is detected or the data in which the error cannot be corrected is discarded, replaced with decodable substitute data, and output to the decompression decoding unit 9.

The decompression decoding unit 9 and the reproduced image storage unit 11 are
The description is omitted because it is completely the same as the conventional one. The image output unit 10 converts the image data received from the decompression decoding unit 9 into
The reproduction images are sequentially stored in the reproduction image storage unit 11, and when the storage of the image data for one screen is completed, an interpolation instruction is output to the interpolation unit 15.

Upon receiving the interpolation instruction from the image output unit 10, the interpolation unit 15 substitutes the image data stored in the reproduced image storage unit 11 because the error correction decoding unit 8 cannot detect or correct the error. The interpolation processing is performed on the image data replaced with the data.

Here, the interpolation processing is, as the simplest method, a method of copying neighboring pixel values, a method of performing linear interpolation or curved interpolation from surrounding pixel values, or weighting of surrounding pixel values based on distance. There is a method of calculating the pixel value by performing the selection, and the selection is made in consideration of the accuracy required for the reproduced image.

Next, referring to FIG.
Use to explain. In this device, the transmitting side transmits 1
When the image data of the image on the screen is stored in the original image storage unit 1, the contour value distribution extraction unit 12 extracts the contour value distribution and stores it in the contour value distribution storage unit 13.

Then, the image input unit 2 reads the image data in units of MCU from the original image storage unit 1 and outputs it to the compression coding unit 3, and at the same time, the contour value distribution corresponding to the MCU is the contour value distribution storage unit 13. Is read from the image data and output to the contour determination unit 14, and the contour determination unit 14 determines the contour whether or not the contour is included, and the determination result is output to the compression encoding unit 3.

On the other hand, the image data in the unit of MCU output from the image input unit 2 to the compression encoding unit 3 is the compression encoding unit 3.
Is compressed and encoded in step S1, and an identifier is added based on the determination result from the contour determination unit 14 and output to the error correction encoding unit 4 in the form of identifier + compressed image data.

Identifier output to the error correction coding unit 4+
The discriminating means 41 discriminates whether or not the compressed image data is the MCU including the contour by the identifier, and the MCU containing the contour.
In the case of, the contour coding means 42 performs error correction coding, and in the case of a non-contour-containing MCU, the non-contour coding means 43 performs error correction coding, and the coded data is output to the communication control section 5. The signal is modulated by the communication control unit 5 and sent to the transmission line 6.

On the receiving side, the data received from the transmission line 6 is demodulated by the communication control section 7, and the discrimination means 81 of the error correction decoding section 8 includes an MCU including the contour from the first 1-byte data.
It is discriminated whether or not it is the encoded data of
In the case of U, it is error-correction-decoded by the contour decoding means 82, in the case of a contour-free MCU, it is error-correction-decoded by the non-contour decoding means 83, and when it is uncorrectable, it is replaced with alternative data, and the identifier The compressed image data from which is removed is output to the decompression decoding unit 9.

The compressed image data output to the decompression decoding unit 9 is decompression-decoded, and is sequentially stored in the reproduced image storage unit 11 by the image output unit 10. When the decompression / decoding for one screen is completed, the interpolating unit 15 interpolates the alternative data portion in the reproduced image storage unit 11.

According to the image data communication method and the image data communication apparatus according to the present invention, the contour judgment unit 14 judges whether or not the MCU includes a contour, and in the case of a contour containing MCU, an error correction coding unit. In the case of a contour-free MCU, the error correction coding unit 4 has a high coding rate but only error detection, or an error correction capability Since low error correction coding is performed, a large amount of data is assigned to an MCU that includes a contour, which is important for recognizing an image, and a small amount of data is assigned to an MCU that does not include a contour. There is an effect that the error correction capability of the contour portion can be improved without increasing the transmission data amount, that is, without reducing the transmission efficiency.

Further, the error correction capability is high for some MCUs including contours, and therefore complicated error correction coding processing is performed, and for the remaining MCUs not including contours,
The error correction capability is low, and therefore a simple error correction coding process is performed, and there is an effect that the efficiency of the error correction coding process can be improved.

Further, according to the image data communication method and the image data communication apparatus according to the present invention, in the case of the contour-containing MCU, the error correction decoding unit 8 on the receiving side performs error correction decoding with high error correction capability. In the case of a contour-free MCU, only error detection or error correction decoding with low error correction capability is performed, so the error correction capability of the contour part important for recognizing an image can be improved, and the recognition level is high. There is an effect that an image can be reproduced.

The error correction capability is high for some MCUs that include contours, and therefore complicated error correction decoding processing is performed, and for the remaining MCUs that do not include contours,
The error correction capability is low, and therefore a simple error correction decoding process is performed, which has the effect of improving the efficiency of the error correction decoding process.

Further, according to the image data communication method and the image data communication apparatus according to the present invention, the error correction decoding unit 8 interpolates the data detected by the MCU not including the contour or the data which cannot be corrected. Since the unit 15 performs a simple interpolation process, there is an effect that the processing efficiency can be improved and a good reproduced image can be obtained.

[0059]

EXAMPLES Examples showing the embodiment of the present invention will be described with reference to the drawings. As an example specifically showing the embodiment of the present invention, vertical 400 pixels,
A comparison is made between the case where an original image having a size of 640 pixels in width is compression-encoded by the JPEG method by the conventional image data communication method and the case where it is transmitted by the image data communication method of the present invention. explain.

When an original image with a size of 400 pixels in the vertical direction and 640 pixels in the horizontal direction is divided into 8 × 8 pixel MCUs by the JPEG method and compression-encoded, the total number of MCUs is 4,000,
It is assumed that the data size after compression is 32 Kbytes. Then, the average data size per MCU is 32,000 bytes / 4,000 MCU = 8 bytes. Therefore, in order to simplify the explanation, the compressed image data size after the compression of 1 MCU is considered as a fixed length of 8 bytes.

First, error correction coding is performed on the above-mentioned compressed image data using a conventional image data communication method.
When BCH (127,78) (coding rate 0.61, maximum error correction bit number 7 bits) is used as a conventional error correction coding method, coding after error correction coding for one screen is performed as shown in FIG. The data volume (transmission data volume) is 32,000 bytes / 0.61 = 52,459 bytes. FIG. 5 is an explanatory diagram showing a specific example of error correction coding in the conventional image data communication method.

Next, error correction coding is performed on the above compressed image data using the image data communication method of the present invention. As one embodiment of the present invention, it is assumed that 1696 MCUs of the above 4,000 MCUs are contour-containing MCUs, and for the contour-containing MCUs, BCH (127,64) is used as error correction coding with high correction capability. ) (Coding rate 0.5, maximum error correction bit number 10 bits), and for a contour-free MCU, a CRC code is used as coding for error detection only, and interpolation is performed on the receiving side.

In this case, the coded data amount (transmission data amount) after error correction coding for one screen is, as shown in FIG. 6, a contour-containing MCU and a contour-free MCU (8 + 1) /0.5×1696. + (8 + 1 + 2) × 2304 = 55,872 bytes, which is about the same amount of transmission data as when using the conventional image data communication method. FIG. 6 is an explanatory diagram showing a specific example of error correction coding in the image data communication method of the present invention.

Next, the conventional method and the present invention will be compared in the case of transmitting the error-correction-encoded encoded data through a transmission path having a bit error rate of 1 × 10 ^-2 . First, the error correction code BCH (127,78) used in the conventional image data communication method.
According to this, the bit error rate of the transmission data on the transmission line having the bit error rate of 1 × 10 ⁻² is improved to about 1 × 10 ⁻⁵ . Therefore, the bit error rate of 1 in the image compression data of the original image
When an error is inserted at a rate of × 10 ^-5 and an image reproduction simulation is carried out, there is a large influence on the reproduced image after the error occurs due to the image shift due to the data in which error correction is not possible.

On the other hand, the error correction code BCH (127,64) for the contour containing MCU used in the image data communication method of the present invention.
According to the transmission data in the transmission path of bit error rate 1 × 10 ^-2, the bit error rate is improved to approximately 1 × 10 ^-8. Therefore, an error is inserted into the contour-containing MCU of the original image at a bit error rate of 1 × 10 ⁻⁸ for simulation, and interpolation is performed on the contour-non-containing MCU assuming that an error is detected in all MCUs. As a result, although the boundary region between the contour portion and the flat portion is distorted, there is no deterioration in the contour portion itself, and it is understood that the image information can be easily recognized.

[0066]

According to the first and third aspects of the present invention, it is judged whether or not the coding block includes a contour, the judgment result is judged, and if the contour is contained, the image data after compression coding is judged. And an image data communication method for transmitting image data by performing error correction coding with high error correction capability, and if the contour is not included, image data after compression coding is subjected to error correction coding with low error correction capability. Since the communication device is used, there is an effect that the error correction capability of the contour portion can be enhanced without lowering the overall transmission efficiency.

According to the second and fourth aspects of the invention, the error correction coding performed on the transmission side for the received data is determined, the error correction decoding corresponding to the error correction coding is performed, and the error is further corrected. Since it is the image data communication method and the image data communication device for interpolating the uncorrectable data,
By performing high-level error correction on the contour portion, performing low-level error correction on the portion not including the contour, and interpolating the uncorrectable portion, it is possible to reproduce a highly recognized image.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an image data communication device according to the present invention.

FIG. 2 is an explanatory diagram showing a specific example of a second-order differential filter S (i, j) used in this device.

FIG. 3 is an explanatory diagram showing an example of BCH (127,64) coding used in the present apparatus.

FIG. 4 is an explanatory diagram showing an example of CRC encoding used in the present apparatus.

FIG. 5 is an explanatory diagram showing a specific example of error correction coding in a conventional image data communication method.

FIG. 6 is an explanatory diagram showing a specific example of error correction coding in the image data communication method of the present invention.

FIG. 7 is a configuration block diagram of a conventional image data communication device.

[Explanation of symbols]

1 ... Original image storage unit, 2, 2 '... Image input unit, 3,
3 '... compression encoding unit, 4, 4' ... error correction encoding unit,
5 ... Communication control unit, 6 ... Transmission path, 7 ... Communication control unit,
8, 8 '... error correction decoding unit, 9 ... decompression decoding unit,
10 ... Image output unit, 11 ... Reproduced image storage unit, 12 ...
Contour value distribution extraction unit, 13 ... Contour value distribution storage unit, 14
... Contour determination section, 15 ... Interpolation section

Claims (4)

[Claims] 1. An image for reproducing an image by dividing an image to be transmitted on the transmitting side into encoded blocks, compression-encoding, further error-correcting encoding and transmitting, and error-correcting decoding on the receiving side and further expanding and decoding. In the data communication method, it is determined whether or not each of the coded blocks includes a contour, the determination result is determined, and for the coded block including the contour, error correction capability is applied to image data after compression coding. Is characterized in that high-error-correction coding is performed, and the image data after compression coding is subjected to error-correction coding with low error-correction capability for a coding block that does not include a contour, and the image data is transmitted. Image data communication method. 2. The data transmitted by the image data communication method according to claim 1, receiving the data, discriminating the error correction coding performed on the transmitting side for the received data, and receiving the received data based on the discrimination result. An image data communication method, characterized in that data is subjected to error correction decoding corresponding to the error correction coding performed on the transmitting side, decompression decoding is performed, and data that cannot be error corrected is interpolated. 3. An image data communication apparatus in which a transmitting side has a compression encoding unit for compressing image data in units of encoded blocks and an error correction encoding unit for performing error correction encoding of the compressed image data and transmitting the error corrected encoding data. In, the provision of a contour determination unit for determining whether the coding block includes a contour,
The error correction coding unit discriminates the judgment result by the contour judgment unit, performs error correction coding with high error correction capability when the contour is included, and error correction with low error correction capability when the contour is not included. An image data communication device comprising an error correction coding unit that performs coding and transmits. 4. An error correction decoding unit that receives the transmission data transmitted from the image data communication device according to claim 3 and corrects an error, and a decompression decoding unit that decompresses the corrected image data. In the image data communication device having a section, the error correction decoding section determines the error correction coding performed on the transmission side with respect to the reception data, and based on the determination result, the reception data on the transmission side. Image data characterized by being an error correction decoding unit for performing error correction decoding corresponding to the performed error correction encoding, and having an interpolation unit for performing interpolation on image data that has not been error corrected. Communication device.