JPH0974539A - Recompression inhibit controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recompression inhibit controller which can inhibit as necessary the recompression of the image data that are recorded on a recording medium. SOLUTION: The image data recorded on an IC memory card M are recompressed with a higher rate than that of the image data and then recorded again on the memory card M, so that the idle capacity of the card M is increased. When the image data are first recorded on the card M, a flag is stored in a flush memory 45 to show the inhibition of recompression of the image data. In a recompression mode, the recompression is inhibited for the image data as long as the inhibition flag is set after the reference to the recompression inhibition flag area of the memory 45. In such a constitution, the recompression is inhibited for the image data whose picture quality should be maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device provided in, for example, a still video camera, and prohibiting a recompression operation for further compressing image data that is compressed and recorded on a recording medium, as necessary.

[0002]

2. Description of the Related Art Conventionally, a still video camera using an IC memory card as a recording medium is known. The amount of image data is extremely large, and therefore one I
There is a certain limit on the number of frames (number of images) recorded on the C memory card. Therefore, there has been proposed a method of increasing the number of frames recorded in one IC memory card by compressing the original image data by a predetermined algorithm and recording the compressed image data in the IC memory card.

However, when the image data is compressed and recorded, fine image information is lost due to the omission of pixel information, and deterioration of image quality is unavoidable. In order to solve such a problem, a still video camera has been proposed which records image data in an IC memory card in an uncompressed or compressed state depending on the photographer's selection.

[0004]

On the other hand, if all the image data is recorded in a non-compressed state, even the image data that does not need to maintain high image quality occupies a wide area of the recording area of the IC memory card. As a result, the area for recording other image data becomes insufficient, making effective use of the IC memory card difficult. Therefore, it is conceivable to compress the image data already recorded in the IC memory card at a higher compression rate (hereinafter referred to as recompression). However, when the image data is recompressed in this way, the information of the image is reduced. Therefore, a sufficient image quality cannot be obtained at the time of reproducing the image, and it is not preferable to recompress the image that needs to retain the image quality.

It is an object of the present invention to provide an apparatus for prohibiting recompression of image data already recorded on a recording medium as needed.

[0006]

A recompression prohibition control apparatus according to the present invention includes a memory having a recompression prohibition flag area corresponding to image data recorded on a recording medium, and a recompression prohibition flag area. A prohibition flag setting means capable of setting a flag indicating prohibition of recompression at an address corresponding to a frame of image data for which recompression is prohibited, and a memory is referred at the time of recompression operation of image data to respond to the flag. And a recompression inhibiting means for inhibiting recompression.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external view of a still video camera to which an embodiment of the present invention is applied.

A viewfinder 12 is provided on the rear surface of the camera body 11.
And a display device 13 are provided. A mode switching button 14 for switching the operation mode of the still video camera among the shooting mode, the reproduction mode and the recompression mode on the side of the viewfinder 12 opposite to the display device 13 is recorded on a recording medium. A frame advance / return button 15 for designating a frame of the image data when reproducing the image data is provided.

On the upper surface of the camera body 11, a release button 16, a compression rate switching button 17 and a recompression prohibition button 19 are provided.
Is provided. The release button 16 is used as an operation button for recompressing image data recorded on a recording medium as described later, in addition to the shutter release operation. The release button 16 is provided with a two-step switch. When the release button 16 is half pressed, the first switch (photometric switch) is turned on, and when it is fully pressed, the second switch (release switch) is further turned on. There is. The recompression prohibition button 19 is provided to prohibit recompression of the image data, and this prohibition process is performed when the image data is recorded on the recording medium, as described later.

A slot 1 for inserting an IC memory card M, which is a recording medium, on the side surface of the camera body 11.
8 are formed.

FIG. 2 is a block diagram showing the circuit configuration of this still video camera. A zoom drive circuit 22, a focus drive circuit 23, and an iris drive circuit 24 are connected to the photographing optical system 21. These circuits 22, 2
3, 24 are controlled by a system control circuit 25, and zooming, autofocusing, and automatic exposure of the photographing optical system 21 are performed. A half mirror 26 is arranged behind the photographing optical system 21. Half mirror 26
One of the lights divided by is guided to the finder optical system 27, and the other is guided to the CCD 28. CCD28 is
It is driven by the CCD driver 32 which is controlled based on the synchronization signal output from the synchronization signal generation circuit 31, and the synchronization signal generation circuit 31 is controlled by the system control circuit 25.

The image signal output from the CCD 28 is subjected to predetermined processing in the process circuit 33 and then A /
It is converted into digital image data in the D converter 34 and stored in the image memory 35. The image data stored in the image memory 35 is read from the image memory 35 and subjected to a predetermined process in the image processing circuit 36 when being recorded in the IC memory card M. Storage and reading of image data in the image memory 35 are performed under the control of the address control circuit 37 controlled by the system control circuit 25.

The image data output from the image processing circuit 36 is recorded in the IC memory card M via the memory card control circuit 41 and the connector 42. The image data can be output to a monitor device (not shown) via the interface circuit 43. When recording image data on the IC memory card M, the image data can be compressed by the image compression circuit 44. The image data compressed and recorded in the IC memory card M is subjected to decompression processing in the image compression circuit 44 when read out from the IC memory card M.

In the system control circuit 25, an operation section 51 such as a mode switching button 14, a frame advance / return button 15, a recompression prohibition button 19 and the like, a display device 13 for displaying a setting state and the like of the operation of this still video camera, Power 5
2 is connected, and a strobe 54 is connected via a strobe control circuit 53. Further, the system control circuit 25 is connected to a flash memory 45 which is a non-volatile memory used for controlling prohibition of recompression. In addition, the system control circuit 25
An IC card lock mechanism (not shown) is connected, which allows the IC memory card to be taken out and loaded under the condition where the power switch of the camera body is turned off (that is, the power is not supplied to the system control circuit 25). Not possible, IC of system control circuit 25
Erroneous recognition of the memory card is prevented.

In this embodiment, the image data is recorded in the IC memory card M in the non-compression mode, the low compression mode or the high compression mode. When the file size of the original image data is 16, as shown in FIG. 3, the file size of the image data recorded in the non-compression mode is also 16. The file size of the image data recorded in the low compression mode is 4, and the file size of the image data recorded in the high compression mode is 1. That is, the ratio of the file size in the low compression mode to the file size in the non-compression mode is 1/4, and the ratio of the file size in the high compression mode to the file size in the non-compression mode is 1/16. The compression process is JPEG (Joint Photographic Exper
t Group) algorithm.

In the present embodiment, the recompression process means
This means a process of changing the file size of the image data already recorded in the IC memory card to a smaller size. In this recompression process, if the image data recorded in the IC memory card is recorded in the low compression mode, the image data is once expanded in the compression / expansion circuit 44 to return to the non-compression state, and then again in the high compression mode. Compress. When the image data recorded in the IC memory card is recorded in the non-compression mode, the image data is compressed in the compression mode with the lowest compression rate.

As will be described later, the IC memory card M has already been used.
By recompressing the image data recorded in
The free space of the IC memory card M can be increased. For example, if the image data in the non-compression mode is compressed by one stage, a free space (reference numeral R1 in FIG. 3) capable of recording 12 frames of the image data in the high compression mode is generated. There is a free space (reference numeral R2 in FIG. 3) capable of recording three frames of image data in the compressed mode. As described above, the free space (R) generated by the image data to be recompressed is compressed in the high compression mode.
1, R2) is referred to as a latent free space here. That is, the number of frames corresponding to the latent free space is 12 in the case of image data in the non-compression mode and 3 in the case of image data in the low compression mode.

On the other hand, if the image data that needs to retain the image quality is recompressed, the image quality of the reproduced image deteriorates. Therefore, in this embodiment, recompression of image data can be prohibited as necessary. Next, in FIG.
The recompression and its inhibition control will be described with reference to FIG.

FIG. 4 is a flow chart of the main program, which is executed when the power switch is turned on.

In step 81, the prohibition flag set interrupt process, that is, the interrupt process for setting the prohibition flag (the flowchart of FIG. 8) is prohibited. That is, the prohibition flag set interrupt is valid only for 5 seconds after shooting, and the prohibition flag set interrupt is prohibited when the main program is started. In step 82, the card removal interrupt process (flowchart in FIG. 13) is prohibited regardless of the presence or absence of the IC memory card M. this is,
This is because shooting, recompression, and reproduction processing cannot be executed unless the card insertion interrupt processing (flowchart in FIG. 5) is executed. That is, the card insertion interrupt is enabled after the card removal interrupt process is prohibited. In step 83, the card insertion interrupt process, that is, the interrupt process (flowchart in FIG. 5) executed when the IC memory card M is inserted into the slot 18 is permitted.

At step 84, it is judged if the IC memory card M is already installed in the slot 18. This determination is made based on the card detection signal output when the IC memory card M is inserted into the slot 18 and a predetermined terminal is grounded. The card detection signal is input to the interrupt terminal of the system control circuit 25, the card detection signal is at the high (H) level when the IC memory card M is not mounted in the slot 18, and the IC memory card M is in the slot 18. When installed, the card detection signal is at low (L) level.

When the card detection signal is at L level, in step 85, the card insertion processing program shown in FIG. 5 is executed.

In FIG. 5, in step 101, it is detected whether or not the IC memory card M is mounted in the slot 18 according to the level of the card detection signal. IC
This program ends immediately when the memory card M is not loaded in the slot 18 (that is, when the card detection signal is at the H level), but when it is loaded (that is, when the card detection signal is at the L level). , Step 102 and subsequent steps are executed. In step 102, the IC memory card M in the RAM in the system control circuit 25 is initialized, and based on the attribute information written in the IC memory card M, the predetermined data in the RAM is rewritten to the initial value. Step 10
In 3, the maximum number of recordable frames is calculated. This maximum recordable frame number is the maximum recording capacity of the loaded IC memory card M, that is, the total writable storage capacity recognized from the attribute information of the IC memory card M is recorded at the maximum compression rate. This is the total number of frames that can be recorded when

At step 105, the address of the flash memory 45 is written at a predetermined address of the RAM in the system control circuit 25, whereby an area having the same number of bits as the maximum recordable frame number obtained at step 103 is created. Reserved in the flash memory 45. That is, when 16 frames of image data can be recorded in the IC memory card M, a 16-bit area is secured in the flash memory 45. This area is an area in which the recompression prohibition flag is stored. Next, in step 107, the card insertion interrupt process is prohibited, and in step 108, the card removal interrupt process is enabled and the program ends.

The card insertion processing program (FIG. 5) is executed in step 85, and the IC memory card M is replaced with a new one while waiting for photographing (for example, while step 86 in FIG. 4 is repeatedly executed). Even when the IC memory card M is replaced, when the IC memory card M is inserted, the card detection signal changes from the H level to the L level so that the interrupt processing is performed. Also, the card insertion processing program is forcibly executed when the power of the present still video camera is turned on. That is, the card insertion processing program is normally interrupted by a change in the card detection signal, but the IC memory card already loaded before the power switch is turned on and the IC memory card to be managed in the flash memory are In order to prevent a mismatch, in this case, the interrupt process is forcibly executed instead of the interrupt process.

Referring again to FIG. 4, in step 86, it is determined whether or not the IC memory card M is loaded, as in step 84. Step 86 is repeatedly executed while the L level card detection signal is not output, but when the L level card detection signal is output,
That is, when it is confirmed that the IC memory card M is inserted in the slot 18, the photographing process, the recompression process, or the reproduction process is executed in step 87 and subsequent steps.

At step 88, it is judged if the photographing mode is set. When the photographing mode is set, in step 88, the photographing process shown in FIGS. 6 and 7 is executed. This photographing process is executed by the system control circuit 25, and is not executed when the IC memory card M is not attached.

When it is determined in step 87 that the photographing mode is not set, it is determined in step 89 whether the recompression mode is set.
When the recompression mode is set, in step 90, the recompression process is executed. This recompression process is also executed by the system control circuit 25, and is not executed when the IC memory card M is not attached.

When it is determined in step 89 that the recompression mode is not set, it is determined in step 91 whether the reproduction mode is set.
When the reproduction mode is set, the reproduction process is executed in step 92, and the image recorded in the IC memory card M is displayed by, for example, the display device.

When it is determined in step 91 that the reproduction mode is not set, or in step 8
After each processing of 8, 90 and 92, the process returns to step 86. That is, it is confirmed that the card detection signal is output, that is, that the IC memory card M is mounted in the slot 18, and if this mounting is confirmed, the process proceeds to step 87 and the above-described processing is executed.

6 and 7 are flowcharts of the photographing process executed in step 88 of FIG. In step 123, for example, the frame number stored in the header portion of the image data recorded in the IC memory card M is referred to, and the current frame number K for photographing is detected. Step 1
At 24, it is detected whether or not the release button 16 is half pressed. When the release button 16 is half pressed, the automatic focusing (AF) process is performed in step 125, and the taking lens of the taking optical system 21 is set in focus by the focus driving circuit 23. Next, at step 126, automatic exposure (AE) processing is performed, and the aperture of the photographing optical system 21 is set to a predetermined aperture state by the iris drive circuit 24.

In step 127, the release button 16
It is determined whether or not is fully pressed. When the release button 16 is not fully pressed, steps 128 to 13
5 is skipped, but when the release button 16 is fully pressed, the routine proceeds to step 128, where the compression rate is detected. This compression rate is set by the compression rate switching button 17, and in the present embodiment, any of the non-compression mode, the low compression mode and the high compression mode can be set. In the non-compression mode, the image data is recorded in the IC memory card M without being compressed, and in the low compression mode, the image data is 1
Mode for compressing to / 4 and recording to the IC memory card M,
The high compression mode is a mode in which image data is compressed to 1/16 and recorded in the IC memory card M. Step 129
Then, the imaging process is executed. That is, the image picked up by the CCD 28 is subjected to predetermined processing in the process circuit 33, the image processing circuit 36 and the like.

At step 130, it is judged if the non-compression mode is set. When the non-compression mode is set, step 131 is skipped, but when the low compression mode or the high compression mode is set, compression processing is performed in step 131 to compress the image data. In step 132, the image data is recorded in the IC memory card M. In step 133, the interrupt is permitted, which enables the recompression prohibition flag setting process of FIG. 8 to be executed. Then, after a waiting time of 5 seconds is provided in step 134, step 135
Interrupts are disabled at. That is, step 1
The recompression prohibition flag setting process of FIG. 8 can be executed in 5 seconds of 34.

At step 136, it is judged if the photographing mode is set. If the shooting mode is released, this program ends, but if the shooting mode is still set, the process returns to step 123 and the above-described operation is repeated. For example, while the release button 16 is being pressed halfway, step 123,
The steps 124, 125, 126, 127, 136 are executed in this order, and the AF process and the AE process are repeatedly performed. While the release button 16 remains in the released state, steps 123, 124, 127, 136 are executed in this order.
Only the current shooting frame number K is detected, and virtually nothing is done.

When the recompression prohibition button 19 is pressed for 5 seconds in step 134, the recompression prohibition flag setting process of FIG. 8 is executed. That is, in step 141, the flash memory 45 is accessed, and in step 142
Then, the Kth frame of the recompression prohibition flag area, that is, the bit corresponding to the current frame number is set to 1. FIG. 9 shows an example of the set state of each bit in the recompression prohibition flag area. In this figure, the bit numbers "D0" to "D7" of the address "0H" are from the first frame to 8th.
Bit numbers "D0" to "D7" of the address "1H" correspond to frames 9 to 16 respectively. In addition, from the 17th frame to 2 from the bit number “D0” to “D7” of the address “2H”
It corresponds to each of the 4th frame. That is, in the example of FIG. 9, the recompression prohibition flag is set for the 10th frame and the 22nd frame, and the recompression prohibition flag is not set for the other frames.

10 and 11 show step 9 of FIG.
12 is a flowchart of a program for recompressing the image data recorded in the IC memory card M, that is, a program for recompressing the image data recorded in the IC memory card M. FIG. It is an example showing a change in the recording state in the IC memory card M when recompressing. The operation of the recompression mode will be described with reference to these drawings.

In step 152, the CCD driver 34 is set to the off state, and the image pickup function of the CCD 28 is stopped. In step 153, the recording information of the IC memory card M, that is, the recorded image data is searched, and the recording state of the IC memory card M is detected. Here, as shown in FIG. 12, each image data of File 1, File 4 and File 5 is recorded in the low compression mode, and each image data of File 2 and File 3 is recorded in the high compression mode. It is assumed that the size of (free space) is three frames (three files) of image data recorded in the high compression mode.

At step 154, the IC memory card M
The actual free space, which is the actual free space existing in, is detected, and this actual free space is divided by the file size of the image data when compressed by the high compression rate, and the number of frames N (in the example of FIG. 12, 3 frames are required. That is, the number of frames N is the number of images that can be recorded by compressing the image data at the maximum compression ratio in the actual empty area, and is the maximum value of the number of frames that can be recorded at present (the number of currently recordable frames).

At step 155, a frame of image data to be recompressed is selected. Here, it is assumed that the file 5 is selected as a frame to be recompressed as shown in FIG. In step 156, the flash memory 45 is accessed, and in step 157, a predetermined flag in the recompression prohibition flag area is read. That is, step 15
In step 7, it is determined whether or not the recompression prohibition flag of the frame selected in step 155 is set.
In the example of FIG. 9, the recompression prohibition flag of the fifth frame, that is, the file 5 is 0, so the process proceeds to step 158. That is, the type of compression mode of the frame to be recompressed is determined. Since the file 5 of FIG. 12 is recorded in the low compression mode, step 159 is executed next, and the number of frames N (the number of currently recordable frames) obtained in step 154 and the number of frames (corresponding to the potential free space) ( By adding 3), the maximum value C (the number of recordable frames after recompression, 6 in the example of FIG. 12) of the number of frames that can be recorded after recompression is obtained.

In step 160, the release button 16
It is determined whether or not is pressed halfway. In the recompression mode, the release button 16 is not used for operations such as photometry and distance measurement as at the time of image capturing, but the number of frames that can be photographed after recompression is displayed on the display device 13 or actually recompressed. Used to perform compression.

When the release button 16 is pressed halfway, step 161 is executed, and the number of frames that can be photographed after recompression is displayed on the display device 13. The number of frames is displayed in this order when newly recorded image data is compressed in the non-compression mode, the low compression mode and the high compression mode. As can be seen from FIG. 3, the number of recordable frames after recompression must be 16 or more in order to record the image data in the non-compressed mode, and the recompressed in order to record the image data in the low compression mode. The number of recordable frames must be 4 or more. In the example of FIG. 12, the number of recordable frames after recompression is 6, so the number of recordable frames is 6/16 = 0 when recorded in the non-compressed mode and 6/4 = 1 when recorded in the low compression mode. It is 6 when recorded in the compressed mode. Therefore, in step 159, the numbers 0, 1, and 6 are sequentially displayed, for example, at intervals of 2 seconds.

In step 160, the release button 1
If it is determined that 6 has not been pressed halfway, and after the number of frames that can be shot is displayed in step 161,
Step 162 is executed and it is determined whether or not the release button 16 has been fully pressed. When the release button 16 is fully pressed, steps 163 to 167 are executed, and the image data of the frame selected in step 155 is recompressed.

In step 163, the image data of the selected frame is read from the IC memory card M, and in step 164, the image data is 1 more than the current compression rate.
It is recompressed at a higher compression rate. In the case of the image data of the file 5 in FIG. 12, the current compression rate is 1/4 (low compression mode), and therefore, in step 164, it is recompressed at a compression rate of 1/16 (high compression mode). The recompressed image data is stored in the image memory 35 in step 165. When this storage is completed, step 166 is executed and the image data read in step 163 is deleted from the IC memory card M. Then, in step 167, the recompressed image data is read from the image memory 35 and written in the IC memory card M.

In step 162, the release button 1
When it is determined that 6 has not been fully pressed, step 16
3 to 167 are skipped.

At step 168, it is judged if the recompression mode is still set. If the recompression mode is still set, the process returns to step 154 and the above-described operation is executed, but if the reproduction mode is released, this program ends.

If it is determined in step 158 that the current compression mode of the image data to be recompressed is the non-compression mode, step 171 is executed, and the number of frames N and the potential free space obtained in step 154 are executed. The number of frames (12) corresponding to is added to obtain the maximum value C of the number of frames of the image that can be recorded after recompression. Then, steps 160 and below are executed.

If it is determined in step 158 that the current compression mode of the image data to be recompressed is the high compression mode, further compression cannot be performed, so steps 159 to 167 are skipped.

On the other hand, when it is determined in step 157 that recompression is prohibited, the display device 13 displays in step 172 that recompression is prohibited, and the process proceeds to step 168.
Therefore, the photographer can operate the frame advance / return button 15 to select the image data of another frame as the image data to be recompressed.

FIG. 13 is a flow chart of a card removing process, that is, a program for clearing the recompression prohibition flag area of the flash memory 45 when the IC memory card M is removed from the still video camera. This program is also executed in the system control circuit 25 like the program of FIG. 4, and is interrupted when the card detection signal changes from the L level to the H level.

At step 111, the IC memory card M
Is detected in the slot 18. When the IC memory card M is installed in the slot 18, this program ends immediately, but when it is taken out, steps 112 and thereafter are executed. In step 112, all the information in the RAM set in step 102 of FIG. 5 is cleared except for the information about the recompression prohibition flag area of the flash memory. In step 114, the area of the recompression prohibition flag on the flash memory is cleared to 0 based on the RAM information (that is, the address of the flash memory 45) written in step 105 of FIG. Next, at step 115, this card removal processing is prohibited, at step 116, the card insertion interrupt processing is permitted, and this program ends.

In this way, when the IC memory card M is taken out from the slot 18, all the bits in the recompression prohibition flag area are cleared to 0. Therefore, the same frame whose recompression is prohibited in the IC memory card M is not prohibited from being recompressed in another IC memory card M.

As described above, according to the present embodiment, the image data once recorded on the recording medium such as the IC memory card M can be recompressed if necessary after that.
It becomes possible to record new image data,
The recording efficiency of the IC memory card M can be improved. In addition, since the number of frames that can be taken is displayed after the recompression, the compression rate of newly recorded image data can be appropriately selected.

Further, according to the present embodiment, of the image data recorded in the IC memory card M, the recompression can be prohibited for the image data for which the image quality needs to be maintained. Accidental recompression of the data is prevented.

[0054]

As described above, according to the present invention, the recompression of the image data already recorded on the recording medium can be prohibited as necessary, and the image quality of the specific image data can be surely maintained. can do.

[Brief description of drawings]

FIG. 1 is an external view of a still video camera to which an embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a circuit configuration of the still video camera of FIG. 1;

FIG. 3 is a diagram showing a file size of image data when recorded in a non-compression mode, a low compression mode and a high compression mode.

FIG. 4 is a flowchart of a main program.

FIG. 5 is a flowchart of a program for clearing a recompression prohibition flag area of a flash memory when an IC memory card is attached to a still video camera.

FIG. 6 is a flowchart of the first half of the program showing the processing during the shooting operation of the still video camera.

FIG. 7 is a flowchart of the latter half of the program showing the processing during the shooting operation of the still video camera.

FIG. 8 is a flowchart of a program for recompression prohibition flag setting processing.

FIG. 9 is a diagram showing an example of a set state of each bit in a recompression prohibition flag area.

FIG. 10 is a flowchart of the first half of a program that executes a recompression mode.

FIG. 11 is a flowchart of the latter half of the program that executes the recompression mode.

FIG. 12 is a diagram showing changes in the recording state in the IC memory card when image data recorded in the low compression mode is recompressed in the high compression mode.

FIG. 13 is a flowchart of a program for clearing the recompression prohibition flag area of the flash memory when the IC memory card is removed from the still video camera.

[Explanation of symbols]

 M recording medium

Claims (4)

[Claims] 1. A device provided in an image data recompression device for recompressing image data recorded on a recording medium at a compression ratio higher than the compression ratio of the image data, for controlling prohibition of recompression. A memory having a recompression prohibition flag area corresponding to the image data recorded on the recording medium, and an address corresponding to a frame of the image data for which recompression is prohibited in the recompression prohibition flag area. Providing a prohibition flag setting means capable of setting a flag indicating prohibition of compression, and a recompression prohibition means for prohibiting recompression according to the flag by referring to the memory at the time of recompression operation of image data A recompression inhibition control device characterized by the above. 2. The recompression inhibition control device according to claim 1, wherein the inhibition flag setting means is capable of setting the flag when recording image data on the recording medium. 3. A first prohibition flag clearing means for clearing all of the recompression prohibition flag area when a recording medium is attached to the image data recompression device. The recompression inhibition control device described. 4. A second prohibition flag clearing means for clearing all of the recompression prohibition flag area when the recording medium is removed from the image data recompression device. The recompression inhibition control device described.