John HamannVickey Yeh
Compression of Stereo Images
OutlineBasic Algorithm
Color Compression
Motion Compensation
Conclusion
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
Results
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
Algorithm A
Algorithm A
About 1% Improvement
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
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
Results
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
Questions