METHOD FOR COMPRESSING IMAGE DATA AND IMAGE DATA COMPRESSING SYSTEM
First Claim
1. A method for compressing image data, comprising:
- setting a target data increment of each of N blocks that need to be compressed of an image to be compressed according to a 0th accumulated target data size and an Nth accumulated target data size;
before compressing an nth block among the N blocks, calculating an (n−
1)th accumulated compressed data size of an (n−
1)th block among the N blocks;
calculating an (n−
1)th accumulated target data size of the (n−
1)th block according to the 0th accumulated target data size and the target data increment;
removing X least significant bit(s) of a plurality of sets of data in the nth block when a difference between the (n−
1)th accumulated compressed data size and the (n−
1)th accumulated target data size is smaller than a first predetermined threshold to generate a updated nth block; and
compressing the updated nth block to generate a compressed nth block;
wherein, N and X are finite positive integers, and n is a finite positive integer not greater than N.
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Accused Products
Abstract
A method for compressing image data is provided. The image data includes a file to be compressed, which includes N blocks to be compressed. The method includes: setting a target data increment of each of the N blocks of the file according to a 0th accumulated target data size and an Nth accumulated target data size; before compressing an nth block, calculating an (n−1)th accumulated target data size of an (n−1)th block according to the 0th accumulated target data size and the target data increment; when a difference between an (n−1)th accumulated compressed data size and the (n−1)th accumulated target data size is smaller than a predetermined threshold, removing X least significant bit(s) of a plurality of sets of data in the nth block to generate an updated nth block; and compressing the updated nth block to generate a compressed nth block.
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Citations
12 Claims
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1. A method for compressing image data, comprising:
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setting a target data increment of each of N blocks that need to be compressed of an image to be compressed according to a 0th accumulated target data size and an Nth accumulated target data size; before compressing an nth block among the N blocks, calculating an (n−
1)th accumulated compressed data size of an (n−
1)th block among the N blocks;calculating an (n−
1)th accumulated target data size of the (n−
1)th block according to the 0th accumulated target data size and the target data increment;removing X least significant bit(s) of a plurality of sets of data in the nth block when a difference between the (n−
1)th accumulated compressed data size and the (n−
1)th accumulated target data size is smaller than a first predetermined threshold to generate a updated nth block; andcompressing the updated nth block to generate a compressed nth block; wherein, N and X are finite positive integers, and n is a finite positive integer not greater than N. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An image data compressing system, comprising:
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a compressing module, compressing an image to be compressed according to a predetermined compression algorithm, wherein data of the image comprises N blocks that need to be compressed; and a compression rate control circuit, coupled to the compressing module, comprising; a compressed data accumulating module, calculating an (n−
1)th accumulated compressed data size of an (n−
1)th block among the N blocks before an nth block among the N blocks is compressed according to a block compressed data size that the compressing module generates after compressing the (n−
1)th block;a target data accumulating module, calculating an (n−
1)th accumulated target data size of the (n−
1)th block according to a 0th accumulated target data size and a target data increment of each of the blocks; anda comparing module, outputting a first compression control signal to the compressing module when a difference between the (n−
1)th accumulated compressed data size and the (n−
1)th accumulated target data size is smaller than a first predetermined threshold;wherein, the compressing module further removes X least significant bit(s) of a plurality of sets of data in the nth block to generate an updated nth block when receiving the first compression control signal, and compresses the updated nth block to generate a compressed nth block; and N and X are finite positive integers, and n is a finite positive integer not greater than N. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification