Toa Corporation

Toshio Morohashi

Kazuhiro Shimauchi

Akira Taguchi

Hiroshi Tabuchi

An image compression apparatus and method capable of performing compression with different image qualities within an image. In a mosaic processing unit () of the image compression apparatus, a filtering region divider () divides input image data into a plurality of filtering areas and at least some of the filtering areas are subjected to unification processing for each of the filtering areas by a filtering unit (). On the other hand, a JPEG encoder () divides the image data after the mosaic processing into a plurality of rectangular block areas and each of the block areas is subjected to DCT processing and quantization processing. Here, the filtering area consists of adjacent one or more sets of rectangular areas each consisting of two or more pixels obtained by equally dividing the aforementioned block area by 2n (n is a natural number).

Image compression method, image compression device, image transmission system, data compression pre-processing apparatus, and computer program

To improve the data compression ratio in the data compression/decompression method utilizing the down-sampling process. Image data in a DS area division unit () is divided into a plenty of DS areas and DS areas which are not important are converted into contracted data of the block size by down-sampling in a down-sampling unit (). A relocation unit () allocates two or more contracted data in one DS area, inserts file data into the other portion in the DS area, and removes the DS area where no contracted data is allocated, thereby reducing the entire image size. The image data thus contracted is inputted into a JPEG encoder () and subjected to a DCT process and a quantization process for each block. When performing restoration, decompression is performed by the JPEG decoder and the original location is restored. As for the contracted data, interpolation is performed to restore the image data.

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Hyogo, Japan

Toshio Morohashi