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Compound image compression for real-time computer screen image transmission.

Tony Lin·Pengwei Hao
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Abstract

We present a compound image compression algorithm for real-time applications of computer screen image transmission. It is called shape primitive extraction and coding (SPEC). Real-time image transmission requires that the compression algorithm should not only achieve high compression ratio, but also have low complexity and provide excellent visual quality. SPEC first segments a compound image into text/graphics pixels and pictorial pixels, and then compresses the text/graphics pixels with a new lossless coding algorithm and the pictorial pixels with the standard lossy JPEG, respectively. The segmentation first classifies image blocks into picture and text/graphics blocks by thresholding the number of colors of each block, then extracts shape primitives of text/graphics from picture blocks. Dynamic color palette that tracks recent text/graphics colors is used to separate small shape primitives of text/graphics from pictorial pixels. Shape primitives are also extracted from text/graphics blocks. All shape primitives from both block types are losslessly compressed by using a combined shape-based and palette-based coding algorithm. Then, the losslessly coded bitstream is fed into a LZW coder. Experimental results show that the SPEC has very low complexity and provides visually lossless quality while keeping competitive compression ratios.

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AlgorithmsArtificial IntelligenceComputer GraphicsComputer SystemsData CompressionImage EnhancementImage Interpretation, Computer-AssistedMultimediaNumerical Analysis, Computer-AssistedPattern Recognition, AutomatedSignal Processing, Computer-AssistedVideo RecordingEvaluation StudyJournal ArticleResearch Support, Non-U.S. Gov't

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Tony Lin, Pengwei Hao. 2005. Compound image compression for real-time computer screen image transmission.. https://doi.org/10.1109/tip.2005.849776

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