JPH10341345A - Image data processing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further compress picture data encoded by a joint photographic experts group ITU-TϕT.81(JPEG) system or the like and to compress image data into encoded picture data more reducing a data amount in comparison with the JPEG system or the like. SOLUTION: Still picture data compressed and encoded on the transmission side of JPEG system 1, for example, are constituted by including real data, which encode block data constituted by dividing the image data for each frame for each block data stream, collecting these block data for a prescribed number, and a restart marker showing the joint of block data streams and such encoded picture data are inputted to a restart marker eraser 2. Next, the restart marker in the encoded image data inputted by that eraser 2 is erased and these encoded picture data are further compressed. Moreover, the restart marker erased encoded picture data are transmitted through a communication path 3 to a restart marker inserter 4, and the restart marker is inserted at its original position in the encoded picture data by the inserter 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image data processing system for compressing and encoding image data, and more particularly to an image encoding apparatus for efficiently encoding and compressing image data for each frame, and a JPEG (Joint Photo Graphic Experts). Gr
oop, ITU-T T.81), etc., and an image encoding method for further compressing the image data compressed and encoded by the JPEG method, etc. The present invention relates to an image data processing system for expanding image data.

[0002]

2. Description of the Related Art For example, when image data is transmitted using a communication path or when image data is stored in a storage medium and stored, the image data of each frame to be processed is compression-encoded. By doing so, the amount of data actually processed is reduced. FIG. 8 shows a configuration example of a JPEG system that compresses and encodes image data according to the JPEG method as an example of a system that performs such compression encoding processing of image data. The JPEG method is generally known as an image compression coding method using a lossy method, and this method can significantly reduce the amount of still image data such as natural image data.

FIG. 8 shows an example of a JPEG system using the JPEG baseline method. This system includes a transmitting device 41 for compressing and transmitting image data, and a transmitting device 41 for transmitting the encoded image data. And a receiving device 46 for receiving and decoding the received data. These two devices 41 and 46 are connected via a communication path 45. The transmitting side device 41 has a discrete cosine transform (DCT:
A discrete cosine transformer 42 for performing a discrete cosine transform, a quantizer 43 for performing a quantization process, and a Huffman encoder 44 for performing a Huffman encoding process are provided. Note that the Huffman coding method is known as a coding method using entropy coding.

A receiving apparatus 46 includes a Huffman decoder 47 for performing Huffman decoding, an inverse quantizer 48 for performing inverse quantization, and an inverse discrete cosine transform (IDC).
T: Inverse DCT (Inverse DCT) processing. An example of a processing procedure by the JPEG system having the above configuration will be described with reference to FIG. FIG. 7A shows the transmission-side device 41 described above.
Is shown. Transmission side device 41
When the processing is started (step S81), for example, digitally converted image data is input for each frame,
The input image data for each frame is divided into blocks of 8 × 8 pixels to generate a plurality of block data (step S82). Note that the block data generated in this manner is generally an MCU in the JPEG system.
(Minimum Coded Unit), and FIG. 8 shows an example of the block data B1.

Next, scanning is started for each generated block data (step S83), these block data are transformed and coded by a discrete cosine transform process (step S84), and the DCT coefficients generated by the coding are transformed. By performing quantization, the number of effective DCT coefficients is reduced (step S85). Then, the quantized DC
The T coefficient is Huffman-coded (step S86), and the data thus coded is transmitted and output to the communication path 45 (step S87). Here, when the processing for all the block data to be processed ends (step S88), the processing ends (step S8).
9) If all processing is not completed,
The same processing as described above is performed for the subsequent block data (steps S90 and S84 to S88). With the above processing, the transmission-side apparatus 41 compresses and encodes image data for each frame and transmits and outputs the image data to the communication path 45.

[0009] FIG. 9B shows an example of a procedure of processing by the above-mentioned receiving device 46. In the receiving device 46, when the process is started (step S91),
The coded data is received and input via the communication path 45 (step S92), scanning of the input coded data is started for each block data (step S93), and the coded data is Huffman-decoded (step S93). S94).
Next, after the Huffman-decoded DCT coefficients are inversely quantized (step S95), the DCT coefficients are subjected to inverse discrete cosine transform (step S96), and the data thus decompressed and decoded is displayed on a screen, for example. The output is reproduced (step S97).

Here, when the processing for all the block data to be processed is completed (step S
98), the process is terminated (step S99), and if all the processes have not been completed, the same process is performed for the subsequent block data (step S1).
00 and S94 to S98). FIG. 8 shows the decoded block data B2 of 8 × 8 pixels, and the same data as the block data B1 is reproduced as the block data B2. Further, in the above-described JPEG system, by using a storage medium for storing data, for example, instead of the communication path 45, the transfer of the encoded data between the transmitting apparatus 41 and the receiving apparatus 46 via the storage medium is performed. Can also be performed.

Here, in general, in the above-described Huffman coding process, in order to increase the coding efficiency, it is often the case that the difference value of the DC component in the DCT coefficient is coded. The encoding process of the difference value of the DC component is performed by using the correlation between the block data for each block data sequence in which a predetermined number of the block data, that is, a fixed number of the block data are collected. In general, the above-described encoding processing of image data, that is, encoding processing of real data, is performed in accordance with encoding conditions defined by a plurality of items. , A sequence of segment codes defining the contents of the encoding condition is added. That is, the encoded real data is decoded based on the sequence of the segment codes added in this manner.

FIG. 10A shows an example of the format of encoded image data to which the above-described arrangement of segment codes has been added. That is, in this format, the encoded image data is the SO that defines the start of the image.
A segment code section 51 including a sequence of segment codes defining I (Start Of Image) and the contents of each item of the above-described coding conditions, and the above-described entropy coding according to the coding conditions defined by the sequence of the segment codes. (For example, Huffman coding), an encoded data portion 52 including actual data subjected to encoding processing and a restart marker to be described later, and an EOI defining the end of the image.
(EndOf Image) 53. As described later, the above-described segment code generally includes a marker code that defines an item of an encoding condition and a parameter that defines the content of the item.

FIG. 10B shows an example of encoded image data in the format shown in FIG. 10A, and FIG. 10B shows an example of encoded image data encoded by the JPEG method. Hexadecimal number ("0")
”“ F ”) is shown.
This coded image data is handled in units of data of 1 byte such as “FF”, for example, and the coded image data shown in FIG. 10B includes two bytes of “FFD8” used as the SOI described above. And a 2-byte marker code such as "FFD9" used as the above-mentioned EOI are added to the beginning and end of the data, respectively.

Here, in general, the marker code is composed of 2 bytes as described above, and FIG.
In addition to OI and EOI, marker codes such as “FFDB” that defines an item called a quantization table, “FFC4” that defines an item called a Huffman table, and “FFDD” that defines an item called a restart interval are shown. ing. After the marker code that defines the item of the encoding condition, a parameter that defines the content of the item defined by the marker code is added. For example, in the above-described item of the restart interval, a parameter that defines a predetermined number of restart intervals (restart intervals) is added after the marker code “FFDD”. In general, a segment code that defines the content of each item of the encoding condition is configured from the above-described marker code and a parameter that follows, and the encoding condition for a plurality of items is defined by the arrangement of such segment codes. .

The predetermined number defined by the above-mentioned restart interval is the number of block data included in a block data string when entropy coding (for example, Huffman coding) image data for each frame. Is a fixed number of That is, for example, if the restart interval is defined as ten,
This shows that the block data is encoded using the correlation between the block data for each block data sequence in which ten block data are put together. In addition to the segment code of the restart interval described above, a restart marker indicating a break of each block data sequence is generally added to the encoded real data. Here, as the restart marker, for example, “FFD
Codes such as “0” to “FFD7” are used cyclically, and “FFD0”, “FFD1”, and “FFD2” are included in the encoded real data shown in FIG.
Such a restart marker is shown.

That is, for example, when the restart interval segment code defines that the restart interval is ten, the restart marker "FFD0" is used for each of the ten coded block data.
~ "FFD7" is cyclically added. This restart marker is used, for example, when decoding image data encoded using the correlation between block data, when a transmission error or the like that has occurred in the encoded image data It is used to prevent large propagation to data. That is, for example, for each position where the restart marker is added, the above-described difference value of the DC component and the like are reset and the decoding process is performed.

The position at which the restart marker is added to the encoded actual data can be predicted from the above-described definition of the restart interval (restart interval). The actual data code is the restart marker code ("FFD0" to "F
If the code is the same as FD7 "), a redundant code such as" 00 "is added after" FF "of the actual data to distinguish it from the code of the restart marker, and" FF00D0 "to It is being replaced with data such as "FF00D7".

[0015]

However, in the above-mentioned image compression coding system, a restart interval segment code defining the number of block data included in a block data string is added to the coded real data. In addition, since a restart marker is added to the delimiter of each block data string in the encoded real data, for example, in a process in which an error is unlikely to occur in block data, the above-described processing is performed. There is a problem that it is not necessary to add a restart marker to encoded real data. That is,
Since the break point of each block data string can be specified from the restart interval defined by the segment code of the restart interval, encoding is performed by adding a restart marker to the encoded actual data. There is a problem that the data amount of image data becomes redundantly large. Also, from such a point, there has been a demand to avoid such a problem and to more efficiently compress and encode the image data.

In the above-described image compression encoding method, a sequence of segment codes defining the contents of each item of the encoding condition defined by a plurality of items is added to the encoded actual data. However, since the number of digits in the sequence of the segment codes that define the contents of each item of the encoding condition is large, there is a problem that the data amount of the encoded image data increases. Therefore, from such a point, there has been a demand for further compressing the image data that has been compression-encoded by the above-described JPEG method or the like.

The present invention has been made to solve such a conventional problem, and divides image data of each frame into a plurality of blocks, and encodes the divided block data when encoding the divided block data. It is an object of the present invention to provide an image encoding apparatus capable of efficiently performing compression encoding on encoded image data having a small data amount. In addition, the present invention provides a method in which real data encoded for each block data sequence, such as still image data compressed and encoded by the JPEG method described above, and information of a predetermined number of block data included in the block data sequence. It is another object of the present invention to provide an image encoding method for compressing still encoded still image data that includes a restart marker and a restart marker.

Further, the present invention provides, for example, the above-described JPEG
Like image data compression-encoded by a method, real data compression-encoded according to encoding conditions defined by a plurality of items, and a sequence of segment codes that define the contents of each item of the encoding conditions. It is another object of the present invention to provide an image data processing system which further compresses encoded image data constituted by incorporating an image encoding device by an image encoding device, and decompresses the encoded image data subjected to the compression processing by an image decoding device. Aim.

[0019]

In order to achieve the above object, an image encoding apparatus according to the present invention divides image data for each frame into a plurality of blocks, and encodes the divided block data. The encoding process of the image data is performed as follows. That is, the encoding means encodes the block data for each block data sequence in which a predetermined number of block data are put together using the correlation between the block data, and the adding means encodes the predetermined number of pieces of information into the encoded block data. It is added to image data consisting of columns.

Accordingly, since the data corresponding to the restart marker code shown in the above-mentioned conventional example is not added to the image data thus coded, for example, the image compression coding method such as the JPEG method described above is used. In comparison, image data for each frame can be efficiently compressed into encoded image data having a smaller data amount. The coded image data is added with the predetermined number of pieces of information described above, and from this information, the number of block data included in the block data string is specified. Even if it is not added, encoded image data can be normally decompressed and decoded.

Further, in the image encoding method according to the present invention,
Real data encoded for each block data sequence obtained by grouping a predetermined number of block data obtained by dividing image data for each frame, the predetermined number of information, and a restart marker indicating a break of the block data sequence; Is further compressed by deleting the restart marker from the encoded still image data. Thus, for example, J
Still image data encoded by the still image compression encoding method such as the PEG method can be compressed into encoded image data having a smaller data amount. Note that the encoded still image data includes the predetermined number of pieces of information described above, and from this information the number of block data included in the block data string is specified. Also, the encoded still image data can be normally decompressed and decoded.

Further, in the image data processing system according to the present invention, the actual data compressed and encoded according to the encoding conditions defined by the plurality of items and the segment code of the segment code defining the contents of each item of the encoding conditions are provided. The encoded image data configured to include the sequence is as follows:
While the image data is further compressed by the image encoding device, the encoded image data subjected to the compression processing is decompressed by the image decoding device. That is, in the image encoding device, the compression-side storage means stores a pattern composed of a sequence of segment codes of each item of the encoding condition in association with a substitute code having a smaller number of digits than the pattern, and the compression-side substitute means stores the code. The arrangement of the segment codes in the coded image data is replaced with the corresponding substitute code stored in the compression-side storage means.

On the other hand, in the image decoding apparatus, the decompression-side storage means stores the same contents as the compression-side storage means provided in the image coding apparatus, and the decompression-side substitution means stores the substitute code in the encoded image data. In the corresponding segment code stored in the decompression-side storage means. Therefore, the image encoding device replaces the arrangement of the segment codes in the image data encoded by the image compression encoding method such as the JPEG method with an alternative code having a smaller number of digits, thereby converting the encoded image data. It can be further compressed.

In the image decoding device, the substitute code in the coded image data further compressed by the image coding device as described above is arranged in the original segment code in accordance with the image coding device. Can be replaced.
For example, when image data compressed and encoded by the JPEG method is transferred from the image encoding device to the image decoding device via a communication path or a storage medium, the amount of data required for the communication processing and the storage processing is reduced. It is possible to reduce these factors, and thus these processes can be performed efficiently.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to the drawings. FIG. 1 shows an example in which the image encoding method according to the present invention is applied to a JPEG system 1. In FIG. 1, while still image data is compression-encoded by the JPEG system, compression is performed by the JPEG system. JPEG system 1 for decompressing and decoding encoded still image data
A restart marker deleter 2 for deleting a restart marker from still image data encoded by the JPEG method, a communication path 3 for transmitting data, and a restart marker for inserting a restart marker in encoded image data. A start marker inserter 4 is shown.

The JPEG system 1 is composed of, for example, as shown in the above-mentioned conventional example, a transmitting device for encoding and transmitting image data, and a receiving device for receiving and decoding image data. In this example, as shown in FIG.
By providing the restart marker deleter 2 on the transmitting side of the JPEG system 1 and the restart marker inserter 4 on the receiving side of the JPEG system 1, the codes transmitted through the communication path 3 are provided. The data amount of the coded image data is further reduced.

The restart marker deleter 2 is a JPEG
A means for inputting still image data compressed and encoded by the system 1 from the system 1 or a restart marker (for example, “FFD0” to “FFD7”) as described in the above-described conventional example from input encoded image data. “)”, Means for further compressing the encoded image data by deleting “)”, and means for transmitting and outputting the encoded image data from which the restart marker has been deleted to the communication path 3. The restart marker inserter 4 receives the coded image data from the communication path 3 and inputs the coded image data into the coded image data by inserting a restart marker into the coded image data. And a means for outputting the decompressed coded image data to the JPEG system 1. In the present example, the various processes performed by the restart marker deleter 2 and the restart marker inserter 4 are performed by the CPU developing a predetermined control program in the RAM and executing the program.

Here, the restart marker insertion processing performed by the restart marker inserter 4 described above includes a predetermined number of pieces of information included in the encoded image data, that is, for example, the restart interval of the restart interval shown in the conventional example. This is performed based on the segment code. In the present example, as described above, the predetermined number of pieces of information is information of a fixed number of block data included in a block data string that is a unit of encoding. That is, for example, when five restart intervals are defined, “FFD0” to “FFD” are set for every five block data.
A restart marker such as 7 "is cyclically added to the encoded real data. With this, the restart marker inserter 4 converts the encoded image data received and input from the communication path 3 into the JPEG format described above. Can be decompressed to the original encoded image data corresponding to.

Next, an example of the procedure of the above-described restart marker deletion and insertion processing will be described with reference to the drawings.
FIG. 2 shows an example of the procedure of the restart marker deletion processing by the restart marker deletion unit 2 described above. First, when the compression encoding process of image data is started by the transmission side of the JPEG system 1 (step S1),
The processing parameters and the like in the deletion processing are initialized (step S2), and image data compressed and encoded by the JPEG method is input (step S3). Next, data is read from the input encoded image data, for example, byte by byte from the beginning (step S4), and it is determined whether the read data is data "FF" (step S5). ). In this example, as shown in the above-described conventional example, it is assumed that the image data compressed and encoded by the JPEG method is represented using hexadecimal numbers ("0" to "F"). “(FF) 16” in FIG. 2 indicates that the data is “FF” in hexadecimal notation.

Here, if it is determined that the read data is the data "FF", the data "FF"
Is read (step S6).
It is determined whether the read data is “D0” to “D7” (step S7). As a result, if the read data is the data “D0” to “D7”, the restart markers “FFD0” to “FD0”
The code "FD7" is deleted from the encoded image data (step S8). Also, in the above processing, if the read data is not "FF" (step S5), or the data following "FF" is "FF". If it is not D0 "to" D7 "(step S7), the next 1-byte data is read (step S12), and the same processing as above is performed (steps S5 to S8).

As described above, when the process of deleting the restart marker has been completed for all the encoded image data (step S9), the encoded image data from which the restart marker has been deleted is transmitted to the communication path 3. Output (Step S10) and end the process (Step S11).
If the restart marker deletion processing has not been completed for all the encoded image data, the processing is continuously performed in the same manner as described above (steps S12 and S12).
5 to S8). In this way, the still image data encoded by the still image compression encoding method such as the JPEG method can be further compressed.

FIG. 3 shows an example of the procedure of the restart marker insertion processing by the restart marker inserter 4 described above. First, when the processing is started (Step S21), processing parameters and the like in the insertion processing are initialized (Step S22). Here, in this example, as the initialization of the processing parameter, the processing parameter “r” for cyclically inserting the restart marker is initialized to a value “0”. Next, the encoded image data from which the restart marker has been deleted is
Then, the predetermined number (restart interval) is read from the contents defined by the segment code of the restart interval in the input coded image data (step S24).

Next, the predetermined number of block data (for example, the MCU shown in the above-mentioned conventional example) is detected from the head of the encoded real data (step S25).
Each time a block data string composed of the predetermined number of block data is detected, for example, “FFD0” to “FD0”
A cyclic restart marker “FD7” is inserted at the break of the block data sequence.
Each time a block data string is detected, “p”, which is the remainder of dividing the current value of “r” by 8, is calculated (step S2).
6) For example, a restart marker “FFDp” is inserted at a break between the block data sequence and the next block data sequence (step S27). Then, 1 is added to the value of “r” (step S28), and the process of inserting the next restart marker is performed, thereby obtaining “F”.
Restart markers FD0 "to" FFD7 "can be inserted cyclically.
The calculated value of “p” is substituted for “p” in FFDp ”.

As described above, when the restart marker insertion processing is completed for all the encoded image data (step S29), the processing is terminated (step S30), and all the encoded image data are processed. If the data processing has not been completed, the processing is continuously performed in the same manner as described above (steps S31 and S25 to S25).
28). In this manner, the restart marker is inserted at the original position in the encoded image data from which the restart marker has been deleted, and the encoded image data can be expanded to the original encoded image data by, for example, the JPEG method. it can.

As described above, the actual data encoded for each block data string, information on a predetermined number of block data included in the block data string, and a restart marker indicating a break of the block data string are included. The compression-encoded still image data configured as described above can be further compressed to reduce a large amount of data, for example, from several tens to several hundreds of bytes. Thus, for example, J
When the still image data compressed and encoded by the PEG method is transmitted via a communication path, and the data amount of the encoded image data to be processed is further reduced, so that the JPEG method is used alone. , The efficiency of the processing can be improved. Thus, JPE
For example, image data that has been compression-encoded by the G method or the like can be further compressed with a small amount of calculation, and the practical limit of the image compression and encoding method such as the JPEG method can be extended.

In the above-described embodiment, an example in which coded image data is transmitted via a communication path has been described. However, instead of a communication path, for example, a storage medium such as a floppy disk for storing data may be used. While the coded image data is written to the storage medium by the restart marker deleter 2 described above, the coded image data stored in the storage medium is read by the restart marker inserter 4, so that the code is written between these devices. It is also possible to carry out the transfer of the coded image data.

Next, FIG. 4 shows an example in which the image data processing system according to the present invention is applied to the JPEG system 1. FIG. 4 shows the JPEG system shown in FIG.
The system 1 and the communication path 3, an image encoding device 11 for further compressing image data compressed and encoded by the JPEG method, and an image decoding device 21 for performing decompression processing corresponding to the image encoding device 11 It is shown. In this example, the above-described image encoding device 11 and image decoding device 2
1 constitutes an image data processing system.

In the present embodiment, the various processes performed by the image data processing system described above are executed by the CPU developing a predetermined control program in the RAM and executing it on hardware resources including a processor and a memory. It is performed by The image encoding device 11 includes a segment code encoder 12 for encoding a segment code, the restart marker deleter 2 shown in FIG.
A redundant code (for example, “0” in “FF00” shown in the above-described conventional example) is extracted from the image data encoded by the G method.
0 ") is provided.

The segment code encoder 12 is a compression side storage means 13 for storing a pattern composed of a sequence of segment codes of each item of the encoding condition in association with an alternative code having a smaller number of digits than the pattern. And a compression side substitution unit 14 for replacing the arrangement of the segment codes in the encoded image data with the corresponding substitution code stored in the compression side storage unit 14. In this example, each of the means 13 and 14 described above is a JPE
It is provided corresponding to the segment code used in the G system. That is, in this example, the compression-side storage means 13 is composed of a memory or the like which stores a substitute code in association with a pattern composed of a sequence of segment codes used in the JPEG system.
The PU is configured by expanding a predetermined control program in the RAM and executing the program. As a result, the compression-side substitution unit 14 detects the arrangement of the segment codes used in the JPEG system from the image data encoded by the JPEG system, and replaces the detected arrangement of the segment codes with the substitution code.

Here, the above alternative code is J
It is set according to the number of types of encoding conditions (the number of types of patterns composed of a sequence of segment codes) used in the encoding processing performed in the PEG system 1, and is made up of, for example, a numerical value of 8 bits (1 byte). By using the substitute code, 256 types of encoding conditions can be represented. Note that the substitute code may be any data as long as it has a smaller number of digits than the pattern consisting of the arrangement of the segment codes to be replaced. That is, for example, when the pattern composed of the sequence of the segment codes in the image data encoded by the JPEG system has more digits than 8 bits, the sequence of the segment codes is replaced with the alternative code composed of the 8-bit numerical value. , The image data compressed and encoded by the JPEG method can be further compressed.

The encoding conditions include, for example, JPE
In the case of the G system, the conditions such as the quantization table and the Huffman table shown in the above-mentioned conventional example, the number of pixels and the type of thinning (for example, Y: Cb: Cr = 1: 1: 1,
Conditions such as 2: 1: 1, 4: 1: 1) are defined by the segment code. Also, for example, when the encoding process is always performed under the same encoding condition by the JPEG system 1, the segment code in the encoded image data can be omitted (that is, replaced with a 0-bit substitute code). .

With the above configuration, the segment code encoder 12 encodes the segment code by replacing the arrangement of the segment codes in the encoded image data input from the transmission side of the JPEG system 1 with the substitute code. The encoded image data thus processed is output to the restart marker deleter 2. The substitute code may be replaced with, for example, a position where the segment codes are arranged, or the substitute code may be added to the head of the coded image data, for example. In other words, what is essential is that the replacement code replaced by the compression-side replacement unit 14 can be detected by the expansion-side replacement unit 25 described later.

The restart marker deleter 2 deletes the restart marker from the encoded image data input from the segment code encoder 12 and replaces the deleted encoded image data with the redundant code deleter 15. Output to The redundant code deleter 15 has means for deleting the redundant code in the encoded image data. In this example, the code “FF00” is selected from the encoded image data input from the restart marker deleter 2. Is detected, the redundant code “00” in the detected “FF00” is deleted, and the encoded image data is transmitted and output to the communication path 3.

That is, as shown in the above-mentioned conventional example, the redundant code is added to the encoded image data in order to distinguish the encoded real data from the restart marker. It is not always necessary to leave the redundant code in the encoded image data from which is deleted, and the redundant code may be deleted together with the restart marker from the encoded image data as in this example. In addition,
As shown in FIG. 1, only the process of deleting the restart marker from the encoded image data may be performed. For example, for the encoded image data to which the redundant code is not added, the restart marker is deleted. Only the processing needs to be performed.

The image decoding device 21 includes a redundant code inserter 22 for inserting a redundant code into encoded image data,
A restart marker inserter 4 shown in FIG. 1 and a segment code decoder 2 for decoding a segment code.
3 are provided. The redundant code inserter 22 has means for inserting a redundant code into the encoded image data. In this example, the redundant code inserter 22 converts the actual data “FF” from the encoded image data received and input from the communication path 3. After detection, a redundant code “00” is inserted after the detected “FF”, and the encoded image data is output to the restart marker inserter 4. The restart marker inserter 4 inserts a restart marker into the encoded image data input from the redundant code inserter 22 and outputs the encoded image data to the segment marker decoder 23.

The segment marker decoder 23 has a decompression side storage means 24 for storing the same contents as the compression side storage means 13 provided in the segment code encoder 12 of the image encoding apparatus 11 described above. And a decompression-side substituting unit 25 that replaces the substitute code in the encoded image data with the corresponding segment code stored in the decompression-side storage unit 24. Here, in the present example, the decompression-side storage means 24 is constituted by a memory or the like, and the decompression-side substitution means 25 is constituted by a CPU expanding a predetermined control program in a RAM and executing the program. Thereby, the extension side substitution means 25
Detects an alternative code from the encoded image data and replaces the detected alternative code with the original segment code. With the above configuration, the segment code decoder 23
Decodes the segment code by replacing the substitute code in the encoded image data input from the restart marker inserter 4 with the original segment code, and converts the encoded image data into the JPEG system 1 receiving side. Output to

Next, an example of a procedure of processing by the above-described image data processing system will be described with reference to the drawings.
Since the process of replacing the arrangement of the segment codes with the substitute code and the process of deleting and inserting the restart marker have been described in detail above, the process of deleting and inserting the redundant code will be described in detail below. In FIG.
An example of a procedure of a process performed by the image encoding device 11 described above is shown. First, when image data encoding processing is started by the transmission side of the JPEG system 1 (step S41), processing parameters and the like for processing in the image encoding device 11 are initialized (step S42), and the JPE
The image data encoded by the G method is input (step S43). Next, the above-described segment code encoding process is performed on the input encoded image data (step S44), and the restart marker is deleted from the encoded image data (step S45). Next, the actual data in the encoded image data is read, for example, byte by byte from the top (step S46), and it is determined whether or not the read data is "FF" (step S4).
7).

If the read data is "FF", the next one byte is read (step S).
48), it is determined whether or not the read data is “00” (step S49). If the data is “00”, the redundant code “00” is deleted (step S49). Step S50). In the above process, if the read data is not “FF” (step S47), or if the data following “FF” is not “00” (step S49), the next one byte The data is read (step S54), and the same processing as described above is performed (steps S47 to S50).

As described above, when the process of deleting the redundant code is completed for all the encoded image data (step S51), the encoded image data is transmitted to the communication path 3 (step S52), and the process is performed. The process ends (step S53). If the above-described deletion processing has not been completed for all the encoded image data, the above-described processing is continuously performed (steps S54 and S4).
7 to S50). In this way, the image encoding device 12 can further compress the encoded image data that has been compression-encoded by the JPEG method.

FIG. 6 shows an example of a procedure of processing performed by the image decoding apparatus 21 described above. First, when the process is started (step S61), processing parameters and the like of the process in the image decoding device 21 are initialized (step S62), and the coded image data is received and input from the communication channel 3 (step S63). . Next, the actual data in the input encoded image data is, for example, 1
Reading is performed for each byte (step S64), and when the read data is “FF” (step S64).
65) After that, a redundant code "00" is inserted after the data (step S66). If the read data is not "FF", the next 1-byte data is read (step S71), and the same processing as above is performed (steps S65 to S66).

When the redundant code insertion process is completed for all data as described above (step S6)
7) A restart marker is inserted into the coded image data on which the processing has been performed (step S68), and the segment code is decoded (step S69).
Then, the encoded image data obtained in this manner is represented by J
The output is output to the receiving side of the PEG system 1, and the process is terminated (step S70). If the above-described insertion processing has not been completed for all the encoded image data, the above-described processing is continuously performed (steps S71 and S71).
65-S66). Thus, the image decoding device 21
Thus, the coded image data further compressed by the above-described image coding device 11 can be expanded to the original coded image data by the JPEG method. By this, JPE
The receiving side of the G system 1 can expand and decode the encoded image data input from the image decoding device 21 to reproduce the original image data.

As described above, in the above-described image data processing system, the actual data compressed and encoded in accordance with the encoding conditions defined by the plurality of items and the segment code defining the contents of each item of the encoding conditions Is further compressed by the image encoding device 11 to reduce a large amount of data, for example, several hundred bytes, while the encoded image data which has been subjected to the compression processing is compressed. Can be expanded by the image decoding device 21. Thereby, for example, the data amount of the coded image data transmitted via the communication path 3 can be reduced, and the efficiency of the communication processing can be improved. Further, for example, by using a storage medium instead of the communication path 3, the data amount of the encoded image data to be stored in the storage medium can be reduced.

As described above, in the above-described image data processing system, image data can be efficiently compressed into coded image data having a smaller data amount as compared with the case where the JPEG method or the like is used alone. Further, since image data compressed and encoded by the JPEG method or the like can be further reduced with, for example, a small amount of calculation, the practical limit of the image compression and encoding method such as the JPEG method can be extended. Here, in the above-described embodiment, the image data processing system performs the process of deleting and inserting the restart marker and the redundant code together with the process of replacing the arrangement of the segment codes and the substitute codes, but these processes are not necessarily performed simultaneously. It is not necessary to perform the processing. For example, the J code may be replaced only by a process of replacing the sequence of segment codes with an alternative code having a smaller number of digits than a pattern composed of the sequence.
The image data compressed and encoded by the PEG method or the like can be further compressed.

Further, for example, the marker codes such as SOI and EOI and the marker codes such as the restart marker shown in the above-mentioned conventional example are regarded as the segment codes having no parameters, so that the arrangement of the segment codes including these marker codes can be changed. It can be replaced with alternative code. That is, for example, by replacing the arrangement of the segment codes including the restart markers with the substitute codes, the image data processing system shown in FIG. 4 does not need to include the restart marker deleter 2 and the restart marker inserter 4. Alternatively, the restart marker code may be deleted from the encoded image data, and communication processing of the encoded image data may be performed.

In FIGS. 1 and 4, an example is shown in which the restart marker is deleted from the image data compressed and encoded by the JPEG system 1 to further compress the encoded image data. Instead of such a configuration, for example, a configuration in which image data is compression-encoded without using a restart marker by an image encoding device of the JPEG system (the transmitting device in the above-described embodiment) may be employed. An example of the configuration of an image encoding device in such a JPEG system will be described with reference to FIG. FIG. 1 shows an image encoding device 31 according to the present invention,
The image encoding device 31 includes an input unit 32 for inputting image data, a dividing unit 33 for dividing image data of each frame into a plurality of blocks, and an encoding unit 34 for encoding the divided block data. , An adding unit 35 for adding a predetermined number of pieces of information of the block data included in the block data sequence to the encoded image data, and an output unit 36 for outputting the encoded image data.

The input means 32 is means for inputting image data captured by, for example, a still camera, and outputs the input image data to the dividing means 33. The input unit 32 may be a unit for inputting image data stored in an external memory, for example. The dividing unit 33 divides the image data of each frame into a plurality of blocks, divides the image data of each frame input from the input unit 32 into a plurality of blocks, and divides the block data thus divided. Is output to the encoding means 34. The coding means 34 is means for coding the block data for each block data sequence in which a predetermined number of block data are put together by using the correlation between the block data, and codes the block data input from the dividing means 33. And outputs the result to the adding unit 35.

The adding means 35 is means for adding the predetermined number of pieces of information to the image data consisting of the block data sequence encoded by the encoding means 34.
The predetermined number of pieces of information are added to the image data composed of the block data string input by the above. Note that the predetermined number of pieces of information may be added to any part of the encoded image data. In short, the predetermined number of pieces of information is used when decoding the encoded image data. Any configuration can be used as long as the configuration can be used. As the predetermined number of pieces of information, for example, the same type of information as the segment code of the restart interval shown in the above-described conventional example can be used. The output unit 36 is a unit that outputs encoded image data. For example, the output unit 36 transmits and outputs the encoded image data input from the adding unit 35 to the communication path 3. The output unit 36 may be, for example, a unit that writes encoded image data to a storage medium.

In this embodiment, the above means 32 to 36 are used.
Is configured by a CPU developing and executing a predetermined control program in a RAM in a hardware resource including a processor, a memory, and the like. With the above configuration, in the above-described image encoding device 31, for example, a predetermined number of information corresponding to the segment code of the restart interval shown in the conventional example is added to the encoded image data, while The image data for each frame is compression-encoded without adding a corresponding code to the encoded image data. As a result, the image data for each frame can be compression-encoded into an encoded image frame having a smaller data amount as compared with the JPEG method or the like.

Here, in the embodiment described above, hardware resources including a processor and a memory
The processor executes the control program to delete and insert the restart marker shown in FIG. 1, compress and decompress the encoded image data by the image data processing system shown in FIG. 4, and FIG. 7 above
However, in the present invention, each functional unit for executing these processes may be configured as an independent hardware circuit. Further, the present invention can be understood as a computer-readable storage medium such as a floppy disk or a CD-ROM storing the above-mentioned control program, and the control program is input from the storage medium to the computer and executed by the processor. Thereby, the processing according to the present invention can be performed.

[0060]

As described above, according to the image encoding apparatus of the present invention, the image data of each frame is divided into a plurality of blocks, and the divided block data is divided into a predetermined number of block data. When encoding using the correlation between block data for each data sequence,
While the predetermined number of pieces of information are added to the encoded image data, the code corresponding to the restart marker shown in the above-described conventional example is not added to the encoded image data. The image data can be compression-encoded into encoded image data having a smaller data amount as compared with the encoding method.

According to the image encoding method of the present invention, the actual data encoded for each block data sequence in which a predetermined number of block data obtained by dividing the image data for each frame are collected, And the restart marker indicating the boundary of the block data sequence, the restart marker is deleted from the encoded still image data. Therefore, the still image data encoded by the image compression encoding method such as the JPEG method can be further compressed.

According to the image data processing system of the present invention, the actual data compressed and encoded according to the encoding conditions defined by a plurality of items and the segment code defining the contents of each item of the encoding conditions In the encoded image data configured to include the arrangement of the above, the arrangement of the segment codes in the encoded image data is replaced by the image encoding device with an alternative code having a smaller number of digits than the pattern composed of the arrangement. On the other hand, the substitute code in the coded image data is replaced by the original segment code by the image decoding device.
Image data encoded by an image compression encoding method such as the EG method can be further compressed. For example, when such encoded image data is subjected to communication processing, the amount of data required for the processing can be reduced. it can.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an image encoding method according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a procedure of a restart marker deletion process.

FIG. 3 is a diagram illustrating an example of a procedure of a restart marker insertion process.

FIG. 4 is a diagram for explaining an image data processing system according to the present invention.

FIG. 5 is a diagram illustrating an example of a procedure of a process performed by the image encoding device.

FIG. 6 is a diagram illustrating an example of a procedure of a process performed by the image decoding device.

FIG. 7 is a configuration example of an image encoding device according to the present invention.

FIG. 8 is a diagram for explaining a conventional JPEG system.

FIG. 9 is a diagram illustrating an example of a procedure of encoding and decoding processing according to the conventional JPEG method.

FIG. 10 is an example of image data compressed and encoded by a conventional JPEG method.

[Explanation of symbols]

1. JPEG system, 2. Restart marker deleter, 3. Communication path (storage media), 4. Restart marker inserter, 11. Image coding device, 1.
2 segment code encoder, 13 compression side storage means, 14 compression side alternative means, 15 redundant code deleter, 21 image decoding device, 22 redundant code inserter, 23 ..Segment code decoders, 24
..Decompression-side storage means, 25..Decompression-side substitute means, 31
..Image coding devices, 32..Input means, 33 ..
Dividing means, 34 coding means, 35 adding means,
... 36 output means,

Claims (3)

[Claims] 1. An image encoding apparatus for dividing image data for each frame into a plurality of blocks and encoding the divided block data, wherein the block data is divided into a block data sequence in which a predetermined number of block data are put together. An image characterized by comprising: encoding means for encoding by using correlation between block data; and adding means for adding the predetermined number of information to image data composed of an encoded block data sequence. Encoding device. 2. real data encoded for each block data sequence obtained by grouping a predetermined number of block data obtained by dividing image data for each frame;
An image encoding method for further compressing compressed and encoded still image data including a restart marker indicating a break of a block data sequence, wherein the encoded still image data is An image encoding method comprising deleting a restart marker. 3. A code comprising real data compressed and encoded according to an encoding condition defined by a plurality of items, and a sequence of segment codes defining the contents of each item of said encoding condition. An image data processing system in which encoded image data is further compressed by an image encoding device, while the compressed image data subjected to the compression processing is decompressed by an image decoding device. Compression-side storage means for storing a pattern consisting of a sequence of segment codes for each item of the condition in association with an alternative code having a smaller number of digits than the pattern, and storing the sequence of segment codes in the encoded image data in the compression-side storage means Compression-side substitution means for replacing with a corresponding substitution code stored in the image decoding apparatus. And a decompression-side substituting means for replacing a substitute code in the encoded image data with a corresponding segment code stored in the decompression-side storage means. Image data processing system.