Comparison Study on the Performance of Critically Sampled Pyramid vs. Over-Complete PyramidOverviewMultiresolution and Pyramid CodingCritically Sampled PyramidOversampled PyramidChoosing the FiltersBit AllocationComparison of Rate-distortion PerformanceScalabilityNumber of LayersConclusionsSangeun Han and Yi LiangDec. 4, 2000Comparison Study on the Performance of Critically Sampled Pyramid vs. Over-Complete PyramidEE 368B Project Sangeun Han and Yi LiangOverviewIntroduction of multiresolution and pyramid codingCritically sampled and overcomplete pyramidsBit allocation and quantizationComparison and resultsEE 368B Project Sangeun Han and Yi LiangMultiresolution and Pyramid Codingr=0.09, 0.23, 0.60, 1.00 bppMultiresolution offers excellent coding efficiency.Multiresolution supports scalability.EE 368B Project Sangeun Han and Yi LiangCritically Sampled PyramidH1H022H1H022QQQ22G1G02+2G1G0+InputRecon.ChannelOctave subband codingOriginal Image Decomp. SubbandsEE 368B Project Sangeun Han and Yi LiangOversampled PyramidEE 368B Project Sangeun Han and Yi LiangChoosing the FiltersChoosing filters10152025303540450 1 2 3 4 5Rate [bpp]PSNR [dB]GaussianDecimate/Interp.Avg./BilinearEE 368B Project Sangeun Han and Yi LiangBit AllocationAnalytical formCritically sampled, open-loop oversampledThe “greedy” algorithmMnkkkklllllkngngMRr/222)/(/log21Close-loop oversampled,00,log211021122lrnRlggrLlllllllll , 111111,10,llllllllllllnnnnnnnnnnn where.constdrndDlllEE 368B Project Sangeun Han and Yi LiangComparison of Rate-distortion PerformanceR-D performance comparison101520253035404550550 1 2 3 4 5Rate [bpp]PSNR [dB]Oversampled open-loop, greedy bit alloc.Oversampled open-loop, analytical bitalloc.Oversampled close-loop, L=5Critially sampled,analytical bit alloc.Critically sampled,greedy bit alloc.In general, critically sampled outperforms oversampled in terms of rate-distortion. Reason: oversampling.EE 368B Project Sangeun Han and Yi LiangScalabilityCritically sampled OvercompletePSNR = 28.4 dBPSNR = 25.8 dBPSNR = 28.4 dBPSNR = 22.8 dBPSNR = 27.2 dB PSNR = 27.2 dBPSNR = 23.8 dB PSNR = 20.9 dBEE 368B Project Sangeun Han and Yi LiangNumber of LayersR-D performance by using different number of levels, open-loop oversampled10152025303540450 1 2 3 4 5Rate [bpp]PSNR [dB]L=2L=3L=4L=5L=6R-D performance by using different number of levels, critically sampled101520253035404550550 1 2 3 4 5Rate [bpp]PSNR [dB]L=2L=3L=4L=5L=6Critically sampled OvercompleteEE 368B Project Sangeun Han and Yi LiangConclusionsCritically sampled pyramid outperforms the over-complete pyramid in terms of rate-distortion.Coarse images from overcomplete pyramids show better subjective quality.Other features of overcomplete pyramid: lower complexity, freedom in choosing filters, control of quantization
View Full Document