Image analysis – Image compression or coding
Reexamination Certificate
1996-07-01
2001-07-17
Couso, Jose L. (Department: 2621)
Image analysis
Image compression or coding
C382S239000
Reexamination Certificate
active
06263106
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image data compression device employed in an image data processing apparatus, such as a still video camera.
Still video cameras utilizing IC memory cards as recording media are well known, Since the IC memory card is capable of storing only a limited amount of data, the number of image frames stored as files in the IC memory card is also limited. In order to increase the number of frames in the IC memory card, the image data is compressed in accordance with a compressing algorithm, and then, the compressed image data is stored in the IC memory card. One such compression algorithm is the JPEG (Joint Photographic Experts Group) format, a “lossy” method.
When image data is compressed with a “lossy” compression method, however, the quality of an image reproduced from the compressed image data is not as good as the originally captured image, as minute image information is lost during the process of compression. If an image is compressed to a higher degree of compression, then more image information is lost.
In a still video camera enabling a user to select whether or not image data is compressed when the image data is stored in the IC memory card is suggested, if a user thinks it is not critical to maintain the quality of the image when the image data is stored, in the IC card memory, the user can store the image data compressed. On the other hand, if the user wishes to retain the highest possible quality, the image data can be stored uncompressed.
As the user continues to take and store photographs, the IC memory card becomes full of image data files. If the user, desires to take additional photographs, another IC memory card trusts be used. Alternatively, instead of replacing the IC memory card, the user deletes or compresses image data already stored in the IC memory card. In such a case, the user is more likely to convert a file previously stored in the IC memory card, since no previous images are lost by this solution.
However, once the image data is stored in the IC card memory, it is difficult to identify the image data contained in each file without reproducing the image from the image data on a screen or hardcopy. That is, since it is difficult for the user to identify which images should be high quality and which may be of lower quality without reproducing the images; it is difficult to select which files may be compressed or further compressed to free some of the IC card memory. As described above, if the image data of an image that the user wishes to retain at a higher quality, already stored in the IC memory card, is compressed or further compressed, information will lost from the desired image data, and the image later reproduced from the compressed data is deteriorated.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an image data compression device which enables a user of a still video camera to select image data that is inhibited from being compressed.
The present invention is directed to an image data compression device that satisfies this need. According to one aspect of the invention, an image data recording device includes means for recording a plurality of image data files in a recording medium as recorded image files, and means for storing a plurality of data flags. The plurality of data flags correspond to the plurality of recorded image data files. When an image data file is recorded in the recording medium, a status of a corresponding one of the plurality of data flags can be set to a predetermined status. The image data recording device further includes means for compressing the recorded image data files in the recording medium, and means for inhibiting the compressing means from compressing the recorded image data file if a corresponding one of the plurality of flag data has the predetermined status.
By compressing image data files already recorded in the recording medium, the remaining capacity is increased, and it becomes possible to store additional image data files.
The image data recording device may be provided with means for capturing an image and generating image data. The compressing means compresses the image data generated by the capturing means when the image data file is first recorded in the recording medium.
When the recorded image data file to be compressed by the compressing means has been compressed at a predetermined compression ratio, the compressing means compresses the recorded image data file at a second compression ratio which is higher than the predetermined compression ratio. Thus, even if a compressed image data file is stored in the recording medium, the compressed image data file is further compressed, and the remaining capacity of the recording medium (where additional data can be stored) is increased.
When the image data file to be compressed by the compressing means has been compressed at the predetermined compression ratio, the compressing means expands the compressed image data file and then compresses the expanded image data file at the second compression ratio.
The image data recording device is further provided with means for indicating a remaining capacity of the recording medium. Therefore, a user can determine whether compression of the recorded image data files is necessary in order to record further image data.
The storing means comprises a non-volatile rewritable memory, Therefore, the flags indicating whether compression is inhibited are not deleted, even if the recording device is turned OFF.
The image data recording device further comprises means for determining whether a recorded image data file to be compressed can be compressed further. The compressing means does not compress the image data file to be compressed if it is determined that the image data to be compressed can not be compressed further. For example, if the recording device can store uncompressed image data files, low-compression format image data files, and high-compression format image data files in the recording medium, the uncompressed image data files and the low-compression format image data files can be further compressed, nut the high-compression format image data files are not compressed.
The image data recording device could be a still video camera.
According to another aspect of the invention, an image data compression device, employed in an image recording device, for corresponding a plurality of recorded image data files in a recording medium, the plurality of recorded image data files corresponding to a plurality of images, the image data compression device comprising a memory for storing a plurality of flags, the plurality of flags corresponding to the plurality of recorded image data files, an operable member for setting a status of each of the flags, a data compression circuit for reading recorded image data files out of the recording medium and compressing the image data, a second operable member for selecting a recorded image data file in the recording medium and initiating a data compression by the data compression, and a controller for inhibiting the compression circuit from compressing the image data if a flag corresponding to the recorded image data file to be compressed has a predetermined status.
According to a further aspect of the invention, there is provided a file compression device for compressing a plurality of recorded image data files in a recording medium, comprising: means for storing a plurality of flags, the plurality of flags corresponding to the plurality of recorded image data files, means for setting a status of each of the flags, means for compressing a recorded image data file, means for actuating the compressing means, and means for inhibiting the compressing means from compressing a recorded image data file if the flag corresponding to the recorded image data file has a predetermined status.
REFERENCES:
patent: 5040233 (1991-08-01), Davy et al.
patent: 5060286 (1991-10-01), Miller
patent: 5063608 (1991-11-01), Siegel
patent: 5107345 (1992-04-01), Lee
patent: 5121216 (1992-06-01), Chen et al.
patent: 52413
Asahi Kogaku Kogyo Kabushiki Kaisha
Couso Jose L.
Dang Duy M.
Greenblum & Bernstein P.L.C.
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