PUMA publications for /tag/Quantization,%20vector%20coding,%20variableThu Mar 10 09:18:49 CET 2016Snowbird, UTData Compression Conference (DCC), 2010mar79-88{S}patial {C}onstant {Q}uantization in {JPEG} {XR} is {N}early {O}ptimal2010Annealing, Distortion JPEG Quantization, Rate Simulated Theory, Variable XR, coding, compression, data distortion image optimisation, quantisation rate theory, vector The JPEG XR image compression standard, originally developed under the name HD-Photo by Microsoft, offers the feature of spatial variably quantization; its codestream syntax allows to select one out of a limited set of possible quantizers per macro block and per frequency band. In this paper, an algorithm is presented that finds the rate-distortion optimal set of quantizers, and the optimal quantizer choice for each macro block. Even though it seems plausible that this feature may provide a huge improvement for images whose statistics is non-stationary, e.g. compound images, it is demonstrated that the PSNR improvement is not larger than 0.3dB for a two-step heuristics of feasible complexity, but improvements of up to 0.8dB for compound images are possible by a much more complex optimization strategy.Thu Mar 03 17:45:04 CET 2016Snowbird, UTData Compression Conference (DCC), 2010mar79-88{S}patial {C}onstant {Q}uantization in {JPEG} {XR} is {N}early {O}ptimal2010Annealing, Distortion JPEG Quantization, Rate Simulated Theory, Variable XR, coding, compression, data distortion image optimisation, quantisation rate theory, vector The JPEG XR image compression standard, originally developed under the name HD-Photo by Microsoft, offers the feature of spatial variably quantization; its codestream syntax allows to select one out of a limited set of possible quantizers per macro block and per frequency band. In this paper, an algorithm is presented that finds the rate-distortion optimal set of quantizers, and the optimal quantizer choice for each macro block. Even though it seems plausible that this feature may provide a huge improvement for images whose statistics is non-stationary, e.g. compound images, it is demonstrated that the PSNR improvement is not larger than 0.3dB for a two-step heuristics of feasible complexity, but improvements of up to 0.8dB for compound images are possible by a much more complex optimization strategy.Quantization, vector coding, variableCommunity for tag(s) Quantization, vector coding, variable