Compression of Stereo Images John Hamann Vickey Yeh

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 No Run-Length Encoding Zip the Final Binary Stream

Results

Color Compression Algorithm A Mode 0: Encode Cr, Cb Mode 1: Encode Cr, Cb + Cr Mode 2: Encode Cr, Cb – Cr Algorithm A Variant Mode 0: Encode Cb, Cr Mode 1: Encode Cb, Cr + Cb Mode 2: Encode Cb, Cr – Cb Performs 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 • 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

Conclusion Huffman Coding then Zip outperforms Run-Length Encoding then Huffman Coding Color Compression Using Algorithm A 3 Modes of Operation {Cb, Cb+Cr, Cb-Cr} Provides slight gains Limited by nature of Cb and Cr Motion Compensation Did not prove beneficial

Questions