compression of stereo images
DESCRIPTION
Compression of Stereo Images. John Hamann Vickey Yeh. Outline. Basic Algorithm Color Compression Motion Compensation Conclusion. Basic Algorithm. Discrete Cosine Transform Uniform Quantization No Quantization Tables Directly Store the DC Coefficients Huffman Code the AC Coefficients - PowerPoint PPT PresentationTRANSCRIPT
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John HamannVickey Yeh
Compression of Stereo Images
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OutlineBasic Algorithm
Color Compression
Motion Compensation
Conclusion
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Basic AlgorithmDiscrete Cosine Transform
Uniform QuantizationNo Quantization Tables
Directly Store the DC Coefficients
Huffman Code the AC CoefficientsNo Run-Length Encoding
Zip the Final Binary Stream
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Results
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Color CompressionAlgorithm A
Mode 0: Encode Cr, Cb Mode 1: Encode Cr, Cb + Cr Mode 2: Encode Cr, Cb – Cr
Algorithm A VariantMode 0: Encode Cb, Cr Mode 1: Encode Cb, Cr + Cb Mode 2: Encode Cb, Cr – CbPerforms Markedly Worse
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Algorithm A
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Algorithm A
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About 1% Improvement
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Algorithm B• Estimate Cb, Cr based on Y
• Cb = acb Y + bcb
• Cr = acr Y + bcr
• For each block• Intra-mode• Code acb , acr , bcb , bcb
• For small blocks,• Too expensive
• For large blocks,• Too much MSE
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Motion Compensation• Search for Nearest Match
• Make Decision Based on Lowest MSE
• Give Bonus to Certain Intervals to Cause Clustering of Motion Vectors
• Encode the Residuals Using DCT as Before
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Results
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ConclusionHuffman Coding then Zip outperforms
Run-Length Encoding then Huffman Coding
Color Compression Using Algorithm A3 Modes of Operation {Cb, Cb+Cr, Cb-Cr}Provides slight gainsLimited by nature of Cb and Cr
Motion CompensationDid not prove beneficial
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Questions