Contrast sensitive variance based adaptive block size DCT image compression

I. Field of the Invention A system and method for image compression utilizing adaptively sized blocks and sub-blocks of discrete cosine transform coefficient data is presented. A block size assignment element in the encoder selects the block or sub-block of an input block of pixels to be processed....

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Bibliographic Details
Main Authors Thyagarajan, Kadayam, Merritt, Michael J
Format Patent
LanguageEnglish
Published 04.03.2003
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Summary:I. Field of the Invention A system and method for image compression utilizing adaptively sized blocks and sub-blocks of discrete cosine transform coefficient data is presented. A block size assignment element in the encoder selects the block or sub-block of an input block of pixels to be processed. The selection is based on the variance of pixel values. Blocks with variances larger than a threshold are subdivided, while blocks with variances smaller than a threshold are not subdivided. A transform element transforms the pixel values of the selected blocks into the frequency domain. The frequency domain values may then be quantized, serialized, and variable length coded in preparation for transmission.