JPH0870432A - Device and method for partial expansion - Google Patents

Abstract

PURPOSE: To enable partial expansion at high speed by reading partial data including a part of necessary compressed data and expanding compressed data. CONSTITUTION: An expansion area specifying means 11 specifies through calculation from which position of a restart marker code (RST) among compressed data to which position of an RST the partial expansion should be executed to specify an expansion area based on an area specifying parameter inputted from an input means 8 and the table of an RST stored in a data buffer 10. A reading area specifying means 12 specifies a sector block including the specified expansion area as a reading out area. Reproducing means 2 reads out the sector block being this reading area from a recording medium 1 and allows an expansion buffer 3 to store data of expansion area. An expansion means 4 expands data in expansion area stored in the extension buffer 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial decompression device and method for decompressing (decompressing) only a part of compressed data. In particular, it relates to a technique for expanding only a part of JPEG compressed data recorded on a recording medium.

[0002]

Various compression encoding methods have been proposed in order to reduce the memory capacity used for recording. When decoding (decompressing) a part of such compressed data, it is a waste of time to decode all the compressed data.

Therefore, Japanese Patent Laid-Open No. 4-347781 (G06F15 / 66) discloses a technique for partially decompressing and expanding a necessary portion of compressed data recorded in advance on a recording medium. This technique reads all the compressed data recorded on a recording medium and partially expands a part of the read compressed data.

[0004]

However, in this technique, since all the compressed data recorded on the recording medium is read, it takes time to read the compressed data, and a part of the compressed data having a large amount of data is partially expanded. In this case, there is a problem that the total processing speed becomes slow. The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a partial expansion device and method capable of performing partial expansion at a higher speed.

A further object of the present invention is to provide a partial decompression device and method adapted to a general recording medium. That is, a general recording medium is accessible in units of sectors, and the minimum unit of partial reading is in units of sectors.

[0006]

The present invention provides a recording medium (1)
In the partial decompression method of reading compressed data from the compressed data and expanding some of the compressed data necessary for reproducing a specified part of the compressed data, reading the compressed data from the recording medium (1). Is characterized in that partial data including the necessary partial compressed data is read.

Furthermore, the present invention is characterized in that the reading of the compressed data is performed in units of sectors including the part of the compressed data. Further, in the present invention, the compressed data is data compressed by the JPEG method, and the part of the compressed data necessary for reproducing the specified part is
A list marker including this specified partial area
It is characterized in that it is an area (extended area) partitioned by a code.

Further, according to the present invention, the compressed data is JPE.
This is data compressed by the G system, and a part of the compressed data necessary for reproducing the specified part is a restart marker code including the specified part of the area. The recording medium (1), which is an area (extended area) divided by
The compressed data read from the
It is characterized in that it is a sector including an area divided by a code.

Further, the partial decompression apparatus of the present invention comprises a recording medium (1) on which compressed data is recorded and decompression area designating means (11) for designating a part of the compressed data as a decompression area.
And a read area designating means (12) for designating a sector block including the decompressed area designated by the decompressed area designating means (11) as a read area, and the data of the sector block, which is the read area, on the recording medium ( It is characterized in that it is provided with a reproducing means (2) for reading from 1) and a partial expanding means (4) for expanding the data read by the reproducing means (2).

Further, in the partial decompression device of the present invention, the partial decompression means (4) decompresses the data corresponding to the decompression area among the data read by the reproduction means (2). And Further, the partial decompression device of the present invention stores a recording medium (1) on which compressed data compressed in block units (for example, 8 × 8 pixel units) is recorded and a partial block area of the compressed data. Decompression area designating means (11) designated as a decompression area, and this decompression area designating means (11)
A read area designating means (12) for designating a sector block including the decompressed area designated by as a read area;
Reproducing means (2) for reading the data of the sector block which is the read area from the recording medium (1), and the reproducing means
And a partial decompression unit (4) for decompressing the data read in (2) in block units.

Further, in the partial decompression device of the present invention, the partial decompression means (4) decompresses the data in the decompression area among the data read by the reproduction means (2) in block units. Is characterized by. Further, the partial decompression device of the present invention is characterized in that the read area designating means (12) designates a minimum sector block including the expanded area as a read area.

Further, the partial decompression device of the present invention is characterized in that the compressed data is data obtained by compressing image data. The partial expansion device of the present invention is a lister.
A recording medium (1) in which a JPEG compressed data having a marker-code (hereinafter, RST) inserted therein is recorded,
A decompression region that designates as a decompression region from the position of the RST indicating the decompression start position to the position of the RST indicating the decompression end position based on the RST table that holds all the positions of the RST inserted in the JPEG compressed data. A designating means (11); a read area designating means (12) for designating a sector block from the read start sector before the expansion start position to the read end sector after the expansion end position as a read area; A reproducing means (2) for reading the data in the reading area from the recording medium (1),
Of the data read by the reproducing means (2), a start unnecessary data receiving means (5) for receiving data from the read start sector to the expansion start position, and the reproducing means
Of the data read in (2), the partial expansion means (4) for expanding the data from the expansion start position to the expansion end position, and the data read by the reproduction means (2),
An end unnecessary data receiving means (5) for receiving data from the expansion end position to the read end sector is provided.

The partial decompression device of the present invention further comprises a recording medium (1) in which a JPEG compressed data having a restart marker code (RST) inserted therein is recorded, Based on the insertion position of the RST, a decompression area designating means (11) for designating a decompression area and a reading for designating a sector block of the recording medium (1) in which the area including the decompression area is recorded as a reading area. Area designating means (12), reproducing means (2) for reading the data of the reading area from the recording medium (1), and partial expanding means (4) for expanding the data read by the reproducing means (2) And is provided.

Further, the partial decompression device of the present invention is a recording medium which is accessible in sector units for recording JPEG compressed data in which a restart marker code (RST) is inserted. Based on (1) and the RST table that holds all the positions of the RST inserted in the JPEG compressed data, the decompression area is extended from the position of the RST indicating the decompression start position to the position of the RST indicating the decompression end position. And a sector block from the read start sector before the expansion start position to the read end sector after the expansion end position,
Readout area designating means (12) to specify as a readout area
And a reproducing means (2) for reading the data in the read area from the recording medium, and a partial decompressing means for decompressing the data from the decompression start position to the decompression end position of the data read by the reproduction means. (4) and is provided.

Further, in the partial decompression device of the present invention, the read area designating means (12) reads a sector block from a sector address immediately before the decompression start position to a sector address immediately after the decompression end position. It is characterized by being specified as a region. Also, the partial decompression device of the present invention is a sector-accessible recording medium for recording JPEG compressed data having a restart marker code (RST) inserted therein, and the JPEG compression. An RST indicating the decompression start position based on the RST table holding all the positions of the RST inserted in the data
From the read start sector several sectors before the expansion start position to the read end sector several sectors after the expansion end position. And a partial decompression unit for decompressing the data from the decompression start position to the decompression end position of the data read from the recording medium. It will be.

Further, according to the present invention, when partially decompressing a part of the compressed data recorded in a recording medium accessible in sector units, the compressed data are all read in advance in the memory, and then the partial decompression is performed. In contrast to conventional devices that
Only the sector area containing the desired partial compressed data is read from the recording medium and the partial expansion is performed.

[0017]

According to the present invention, in the partial decompression method of reading compressed data from the recording medium (1) and decompressing a part of the compressed data necessary for reproducing a specified part of the compressed data, Partial data including necessary part of the compressed data is read from the recording medium (1).

In the present invention, this reading is performed in sector units. Further, the present invention can be applied to JPEG compressed data. Further, in the present invention, JPEG
R that holds the position of the RST inserted in the compressed data
Based on the ST table, the RST position indicating the extension start position and the RST position indicating the extension end position are designated,
The data from the read start sector before the decompression start position to the read end sector after the decompression end position is read from the recording medium, and from this data, the data from the decompression start position to the decompression end position is read. Extend.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. First, the compressed data used in this embodiment will be briefly described. This compressed data is the well-known JPEG (J
oint Photographic Expert Group) method, the compression algorithm is the magazine interface issued by CQ publisher December 1991 P160-P182 or Maruzen Co., Ltd. June 1991. Published on the 30th, edited by Hiroshi Yasuda, "International Standard for Multimedia Coding".

The restart marker code (hereinafter referred to as RST) is applied to the compressed data compressed by this compression method.
You can insert a number of codes. This R
The ST is used to reset the predicted value of the DC coefficient in the DCT transform, and thus it is possible to prevent the error propagation due to the transmission error of the compressed data.

That is, when a transmission error occurs in compressed data without RST, the error propagates to the entire image after the error occurs. But R
If ST is inserted in the compressed data, even if a transmission error occurs, the error propagation can be suppressed by the next RST. This indicates that the compressed data is delimited by the RST, and the blocks delimited by the RST become independent partial compressed data, which can be expanded independently.

Therefore, it is possible to partially decompress a part of the compressed data using this RST. Next, this embodiment will be described. FIG. 1 is a diagram showing the functional blocks of this embodiment. The recording medium 1 is, for example, an optical disk or a hard disk. Since the recording medium 1 is accessible in sector units, it is possible to read and write in sector units.

Image data is recorded on the recording medium 1 by JPE.
The G-compressed compressed data and the index information including the recording start sector address of the compressed data on the recording medium 1, the data size of the compressed data, various flags, and the like are integrally recorded. Further, on the recording medium 1, recording positions of all RSTs inserted in the compressed data are recorded. That is, the position information indicating in which byte from the beginning of the compressed data the RST is recorded is recorded in the table format.

The reproducing means 2 is, for example, an optical disk drive or a hard disk drive. Kono reproduction means 2
Is for reproducing the recording medium 1 and reading the recorded contents. The decompression buffer 3 is a buffer that temporarily stores the compressed data reproduced by the reproducing means 3.

The decompression means 4 decompresses the compressed data stored in the decompression buffer 3. Specifically, the decompression means 4 uses the inverse Huffman coding, the inverse quantization, and the inverse two-dimensional DC.
Image data is generated by performing processing such as T conversion. The storage means 5 records the image data output from the decompression means 4. Further, the data output from the reproducing means 2 is recorded. The image data is stored in the display area of the storage means 5,
The data reproduced from the reproducing means 2 is stored in the non-display area of the storage means 5.

The video processing means 6 takes out data from the display area of the storage means 5 and converts it into a video signal. The monitor 7 displays the video signal output from the video processing means 6. The input means 8 is, for example, a keyboard or a mouse. The input means 8 receives an instruction from the operator to this device. For example, an area designating parameter indicating which part of the image is to be output for display, an operation start instruction for partial expansion, and the like are input.

The control means 9 controls the entire apparatus. The control means 9 starts its control in response to a partial decompression operation start instruction input from the input means 8.
The data buffer 10 stores the index information recorded in the recording medium 1 and the RST table. The decompressed area designating means 11 is based on the area designating parameter inputted from the input means 8 and the table of the RST stored in the data buffer 10, from which RST position of the compressed data the compressed data Up to which RST position among them is partially expanded, and the expanded area is designated. Therefore, the decompression start position, which is the head of the decompression region, and the decompression end position, which is the end of the decompression region, are both positions where the RST of the compressed data is inserted.

The read area designating means 12 determines, based on the information of the decompressing area (decompression start position and decompression end position) output from the decompression area designating means 11 and the index information stored in the data buffer 10. It is calculated which sector address of the compressed data to which sector address of the compressed data is read from the recording medium 1, and the read area is designated.

At this time, the read area designating means 12 is
The read start sector, which is the beginning of this read area,
The sector address immediately before the expansion start position is set, and the read end sector that is the end of the read region is specified as the sector address immediately after the expansion end position. Next, the position of the RST inserted in the compressed data will be described.

FIG. 2 shows RS inserted in compressed data.
It is a figure which shows the insertion position of T. This figure is for the image data before the compressed data is compressed. J
In PEG, the image data is divided into unit blocks of vertical 8 pixels × horizontal 8 pixels for compression processing. Therefore, if the size of the image data is, for example, 1040 pixels vertically × 1920 pixels horizontally, there are a total of 31200 unit blocks, namely 130 in the vertical direction and 240 in the horizontal direction.

These unit blocks are one block line in the horizontal direction from the upper left unit block in FIG.
After processing (240), the processing line is lowered by one unit block, and similarly, one block line is processed in the horizontal direction from the leftmost unit block in FIG. With this procedure, JPE
When G-compressed, the RST can be inserted after an arbitrary unit block, but the compressed data in this embodiment is, as shown in FIG. 2, every one block line in the horizontal direction, that is, 240 unit blocks. It is assumed that the RST is inserted and JPEG-compressed each time.

Therefore, for example, if one RST position in the compressed data to the next RST position is extracted and partially expanded, the expanded data becomes image data of one block line in the horizontal direction and its size. That is, 8 pixels vertically × 1920 pixels horizontally. Next, the operation of this embodiment will be described. FIG. 4 is a diagram showing a flowchart of this apparatus.

The operation will be described below with reference to the flowchart of FIG. First, the area designating parameter indicating which part of the image is to be partially expanded is input from the input unit 8, and further, the start instruction of the partial expansion operation is input (step S).
1). Specifically, a rectangular frame (not shown) is displayed on the monitor, and, for example, the coordinate area of the hatched area in FIG. 2 is input as the area specifying parameter.

Next, when the area designating parameter and the operation start instruction are inputted from the input means 8, the control means 9 instructs the reproducing means 2 to record the index information recorded on the recording medium 1 and the index information. Read the RST table and
Instruct to store these in the data buffer 10.
(Step S2). Therefore, the index information reproduced from the recording medium 1 and the RST table are stored in the data buffer 10.

Further, the control means 9 is the extension area designating means 1
1, the area specifying parameter is output to instruct to specify the expanded area indicating the expanded part corresponding to the area specifying parameter in the compressed data (step S
3). The decompression area designating unit 11 identifies the area to be partially decompressed based on the coordinate area of the hatched portion in FIG. 2 input as the area designating parameter and the RST table stored in the data buffer 10.

Specifically, in FIG. 2, a block area of continuous 8 block lines in the horizontal direction from the unit block of the 80th vertical block and the 1st horizontal block to the 87th vertical block and the 240th horizontal unit block. Becomes an extension area. Then, the decompression area designating means 11 determines, from the RST table, the position information of the RST (RST79) immediately before the unit block of the 80th vertical block and the 1st horizontal block, and the unit of the 87th vertical block and the 240th horizontal block. The position information of the RST (RST87) immediately after the block is acquired.

As a result, the decompression area designating means 11 specifies the number of bytes from the head of the compressed data at the decompression start position indicating the beginning of the decompression area and the decompression end position indicating the end of the decompression area. The expansion start position and the expansion end position are output to the read area designating unit 12. The read area designating unit 12 inputs the decompression start position and decompression end position from the decompression area designating unit 11, inputs the index information from the data buffer 10, and actually reads out the data portion from the recording medium 1. The area is designated (step S4).

This will be described with reference to FIG. The relationship between the data size of compressed data obtained by compressing image data and the sector size of the recording medium is generally much larger than the data size of compressed data, which is several tens to several hundreds of times larger than the sector size. . Therefore, when the compressed data is recorded on the recording medium 1, the compressed data is recorded over a plurality of sectors.

FIG. 3 is a diagram schematically showing a state of a sector in the vicinity of the expansion area in the compressed data continuously recorded on the recording medium 1. The shaded area in FIG. 3 is the extension area designated by the extension area designating means 11. In this figure, the decompression start position exists in the sector sandwiched between the sector address (N) and the sector address (N + 1), and the sector address (N
+ K) and the sector address (N + K + 1) have a decompression end position in the sector, and the compressed data in the decompression area is continuously recorded between these two sectors.

The read area designating means 12 acquires the index information from the data buffer 10 and obtains from which sector address of the recording medium 1 the compressed data is recorded. Further, the read area designating means 12 sets the decompression start position (the number of bytes from the head of the compressed data) and 1
The sector address (N) immediately before the expansion start position, which is the head of the expansion area, is calculated from the number of bytes of the sector size.
To get This sector address (N) becomes the read start sector address.

Further, the read area designating means 12 sets the decompression end position (the number of bytes from the head of the compressed data) and 1
Calculated from the number of bytes of the sector size, the sector address (N
+ K + 1) is obtained. This sector address (N + K + 1) becomes the read end sector address. In this way,
The read area from the read start sector address to the read end sector address is specified.

That is, the read area designating means 12 is the smallest continuous sector block including the expanded area (area from the sector address (N) to the sector address (N + K + 1)).
Is designated as the read area. In other words, the read area designating unit 12 specifies the read area such that the read area, which is a part of the compressed data, includes the expanded area.

When the reading area designating means 12 specifies the reading area, it outputs the reading start sector address and the reading end sector address to the control means 9. When the read start sector address and the read end sector address are input, the control means 9 instructs the reproduction means 2 to reproduce the data in the read area from the recording medium 1 (step S5). As a result, the reproduction of the read area from the recording medium 1 by the reproduction means 2 is started.

The control means 9 instructs the reproduction of the read area and stores the data from the read start sector address which is the head of the read area to the expansion start position which is the head of the expanded area in the storage means 5. The storage address of the storage means 5 is controlled so as to be stored in the display area.
(Step S6). Therefore, the data read from the recording medium 1 is sequentially stored in the non-display area of the storage unit 5.

The data stored in this step is unnecessary for partial decompression, and this unnecessary unnecessary start data is simply discarded in the storage means 5. The control means 9 suspends the read operation of the reproducing means 2 when the storage of the unnecessary start data in the storage means 5 is completed. Next, the control means 9 restarts the read operation of the reproducing means 2 and transfers the data from the expansion start position which is the head of the expansion area to the expansion end position which is the end of the expansion area to the expansion buffer 3. The storage address of the decompression buffer 3 is controlled so that it is stored (step S7). As a result, the reading of the reproduction means 2 which has been suspended is restarted, and the read data of the expansion area is stored in the expansion buffer 3.

The control means 9 suspends the read operation of the reproducing means 2 again when the storage of the data in the expansion area in the expansion buffer 3 is completed. Furthermore, the control means 9
Restarts the read operation of the reproducing means 2, and
The storage address of the storage unit 5 is controlled so that the data from the expansion end position which is the end of the expansion region to the read end sector address which is the end of the read region is stored in the non-display area of the storage unit 5. (Step S
8).

As a result, the reading of the reproduction means 2 which has been temporarily suspended is resumed, and the read data is stored in the storage means 5. The data stored in this step is unnecessary data for partial decompression, and this unnecessary unnecessary unnecessary data is simply discarded in the storage means 5. Next, the control means 9 instructs the expansion means 4 to
An instruction is given to decompress the data in the decompression area stored in the decompression buffer 3 (step S9). Therefore, the data in the expansion area, which is a part of the compressed data, is partially expanded.

Further, the control means 9 instructs the image data decompressed by the decompression means 4 to be stored in the display area of the storage means 5. Therefore, the image data (partially decompressed image data, the image of the hatched portion in FIG. 2) is stored in the storage means 5.
Is stored in the display area and is converted into a video signal by the video processing means 6.

When this video signal is output to the monitor 7,
An image of only the shaded portion in FIG. 2 is displayed on the monitor 7 (step S10). In the above-described embodiment, in FIG. 3, the minimum sector unit area (sector address (N) to sector address (N + K +
Although the area up to 1) is the read area, the read area intended by the present application is not necessarily limited to this.

For example, the read start sector address is
Any sector address may be used as long as it exists before the decompression start position and after the head sector address of the compressed data. Further, for example, if the read end sector address is a sector address that exists after the decompression end position and exists before the end sector address of the compressed data,
Any sector address will do.

That is, the read area may be any area as long as it is a sector block including the expanded area within the range in which all the compressed data is not read in order to read the data in the expanded area. Further, in the above-described embodiment, the unnecessary start data in step S6 and the unnecessary end data in step S8 in FIG. 4 are stored in the storage unit 5, but the data is not limited to this.

For example, in order to allow the reproducing means 2 to output the unnecessary start data and the unnecessary end data read by the reproducing means 2 without storing the unnecessary start data and the unnecessary end data in the storage means 3, It goes without saying that the reproduction means 2 may be handshaked to receive only the start unnecessary data and the end unnecessary data.

Further, in the above-mentioned embodiment, the steps S6 and S8 are described in FIG. 4, but the present invention is not necessarily limited to this. For example, if the read start sector address and the decompression start position have the same value (start unnecessary data is 0 bytes), it goes without saying that step S6 may be omitted.

Further, for example, when the decompression end position and the read end sector address have the same value (the end unnecessary data is 0 byte), it goes without saying that step S8 may be omitted. Furthermore, in the above-described embodiment, the case where the expansion area to be partially expanded in the compressed data is physically continuous on the recording medium has been described.
The decompression area of the compressed data, which is partially decompressed, can be applied even when it is not physically continuous on the recording medium, which will be described below.

For example, RST is inserted for each unit block to prepare compressed data obtained by JPEG-compressing image data of 1040 pixels vertically × 1920 pixels horizontally. This allows
2 for each horizontal block line (240 unit blocks)
This means that 40 RSTs have been inserted. For such compressed data, the operator uses the input unit 8 to form a rectangular shape having (vertical 400 pixels, horizontal 800 pixels) and (vertical 800 pixels, horizontal 1600 pixels) as end points of diagonal lines. It is assumed that the coordinate area is input as the area designation parameter. That is, it is assumed that the central area of the image data (vertical 50 unit block × horizontal 100 unit block) is designated.

In this case, each horizontal block line (vertical 1 unit block × horizontal 100 unit block) in the designated coordinate area is recorded on the storage medium 1 at a position physically separated by several sectors. Will be there. That is, although one horizontal block line is physically continuously recorded on the recording medium, one horizontal block line and another certain horizontal block line are
It means that the recording is physically discontinuous on the recording medium.

Even in such a case, first, the process of the flowchart of FIG. 4 is performed on the leading horizontal block line in the designated coordinate area to partially expand one horizontal block line. Next, similar processing is performed on the second horizontal block line to partially expand one horizontal block line. This is repeated until the last horizontal block line in the coordinate area is partially expanded. That is, partial expansion is sequentially performed for each horizontal block line in the area.

In this way, the portion of the designated coordinate area of the compressed data is partially expanded. Further, in the above-described embodiment, the case where the compressed data of the still image is described as the compressed data, but the present application is not limited to this, and may be the compressed data of the moving image, for example.
Further, it may be compressed data of voice.

Further, in the above-mentioned embodiment, the case where the compressed data compressed by the JPEG method is partially expanded has been described, but the present application is not limited to this. For example, M
The compressed data compressed by the PEG method may be partially expanded, or the MMR used in a facsimile machine or the like.
It goes without saying that the compressed data compressed by the method, the MH method, or the MR method may be partially expanded.

Further, in the above-described embodiment, the recording medium 1
Although the case where the compressed data and the RST table are recorded has been described above, the present invention is not limited to this. For example, the compressed data and the RST table may be recorded in different recording media. Needless to say. Further, the RST table may not be recorded. In this case, the compressed data may be once reproduced to search the RST insertion position to create the RST table.

Further, in the above-described embodiment, the input means 8 sets the area designation parameter indicating which portion of the image is to be output for display, and the R necessary for reproducing this area.
The expansion processing is performed with the area delimited by ST as the expansion area. Therefore, the display area and the expansion area do not always match. Therefore, a means may be provided for displaying and outputting the area designated by the area designating parameter among the decompressed areas when they do not match. In addition, the above-mentioned embodiment,
The present invention is merely an example of the present invention, and various modifications can be made if necessary, and the present invention described in the claims includes all such modifications.

The functional blocks of the above-described embodiment are
It is needless to say that the present invention may include some aspect as well, which may be configured by software or hardware as necessary.

[0063]

According to the first to fourteenth aspects of the present invention, the compressed data recorded on the recording medium is not read all but the data necessary for the partial expansion is read. The total processing speed can be increased when partially decompressing the compressed data.

In addition, claims 2, 4, 7, 8, 9 of the present invention
According to Nos. 11, 12, 13, and 14, the compressed data recorded on the recording medium is not all read, but the data of the read area in sector units including the data of the partially expanded area is read from the recording medium. Therefore, the read time of the compressed data can be reduced, and the processing can be speeded up when partially decompressing the compressed data.

In addition, claims 3, 4, 11, 12 of the present invention,
13 and 14, JPE recorded on the recording medium.
Since the G area compressed data is not completely read out and the data in the required area is read out from the recording medium, the time required for reading out the compressed data can be reduced and the processing can be speeded up when partially expanding the compressed data. .

[Brief description of drawings]

FIG. 1 is a diagram showing functional blocks of an embodiment of the present invention.

FIG. 2 is a diagram for explaining JPEG data in which an RST is inserted for each line.

FIG. 3 is a diagram showing a state of a sector of the recording medium of this embodiment.

FIG. 4 is a diagram showing a flowchart of this embodiment.

[Explanation of symbols]

 1 Recording Medium 2 Playback Means 4 Decompression Means 5 Storage Means 11 Decompression Area Designation Means 12 Read Area Designation Means

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Claims (14)

[Claims] 1. A partial decompression method for decompressing compressed data from a recording medium (1) and decompressing a part of the compressed data required to reproduce a specified part of the compressed data, Reading from the recording medium (1) of
A partial decompression method, wherein partial data including the required partial compressed data is read. 2. The partial decompression method according to claim 1, wherein the reading of the compressed data is performed in units of sectors including the partial compressed data. 3. The compressed data is data compressed by the JPEG method, and the part of the compressed data necessary for reproducing the specified part includes the specified part of the area. 2. The partial expansion method according to claim 1, wherein the area is defined by a restart marker code. 4. The compressed data is data compressed by the JPEG system, and the part of the compressed data necessary for reproducing the specified part includes the specified part of the area. The compressed data read from the recording medium (1) is an area partitioned by the restart marker code. The partial expansion method according to claim 1, wherein the partial expansion method is a sector including the sector. 5. A recording medium (1) recording compressed data, a decompression area designating means (11) for designating a part of the compressed data as a decompression area, and a decompression area designating means (11). A read area designating means (12) for designating a sector block including the expanded area as a read area, a reproducing means (2) for reading the data of the sector block which is the read area from the recording medium (1), A partial decompression device comprising a partial decompression unit (4) for decompressing the data read by the unit (2). 6. The partial expansion means (4) is the reproduction means.
6. The partial decompression device according to claim 5, wherein the data corresponding to the decompression area is decompressed from the data read in (2). 7. A recording medium (1) on which compressed data compressed in block units is recorded, and a decompressed area designating means (11) for designating a partial block area of the compressed data as a decompressed area. Read area designating means (12) for designating a sector block including the decompressed area designated by the decompressed area designating means (11) as a read area, and data of the sector block which is the read area is recorded on the recording medium (1). A partial decompression device comprising a reproducing means (2) for reading from the reproducing means and a partial expanding means (4) for expanding the data read by the reproducing means (2) in block units. 8. The partial expansion means (4) is the reproduction means.
8. The partial decompression device according to claim 7, wherein the data in the decompression area of the data read in (2) is decompressed in block units. 9. The portion according to claim 5, wherein the read area designating means (12) designates a minimum sector block including the expanded area as a read area. Extender. 10. The partial decompression device according to claim 5, wherein the compressed data is data obtained by compressing image data. 11. A restart marker code (hereinafter,
Based on a recording medium (1) in which JPEG compressed data in which RST) is inserted and an RST table holding all the positions of the RST inserted in the JPEG compressed data are set, Decompression area designating means (11) for designating an area from the RST position shown to the RST position showing the decompression end position as a decompression area, and reading from the read start sector before the decompression start position to after the decompression end position. A read area designating means (12) for designating a sector block up to the end sector as a read area, a reproducing means (2) for reading the data in the read area from the recording medium (1), and a reproducing means (2). Of the read data, a start unnecessary data receiving means (5) for receiving data from the read start sector to the decompression start position, and the reproducing device. Of the data read in (2), the partial expansion means (4) for expanding the data from the expansion start position to the expansion end position, and the data read by the reproduction means (2), A partial decompression device, comprising: end unnecessary data receiving means (5) for receiving data from the decompression end position to the read end sector. 12. A restart marker code (hereinafter,
A recording medium (1) in which JPEG compressed data in which RST) is inserted is recorded, an expansion area designating unit (11) for specifying an expansion area based on the insertion position of this RST, and the expansion area The recording medium in which the area containing is recorded (1)
The reading area designating means (12) for designating the sector block of as a reading area, the reproducing means (2) for reading the data of the reading area from the recording medium (1), and the reading means (2) for reading. Partial decompression device (4) for decompressing the data, and a partial decompression device. 13. A restart marker code (hereinafter,
Based on a recording medium (1) accessible in sector unit for recording JPEG compressed data having RST) inserted therein and an RST table holding all positions of the RST inserted in the JPEG compressed data. Decompression area designating means (11) for designating a decompression area from the RST position indicating the decompression start position to the RST position indicating the decompression end position, and the decompression end from the read start sector before the decompression start position. A read area designating unit (12) that designates a sector block after the position up to the read end sector as a read area, a reproducing unit (2) that reads the data in the read area from the recording medium, and a read unit that reads the data. A partial decompression means (4) for decompressing the data from the decompression start position to the decompression end position of the outputted data. Partial expansion device. 14. The read area specifying means (12) specifies a sector block from a sector address immediately before the expansion start position to a sector address immediately after the expansion end position as a read area. The partial expansion device according to any one of claims 11 to 13.