Scalar and Vector Quantization

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FAQ Refinement So far, we assumed uniform pdf over maximal ranges, we can refine it by computing the range of distribution adaptively for each block Example: Sena image, 8x8 blocks, 2x8-bit for range per block, 3-bit quantizer Original 8 bits/pixel Quantized 3.25 bits/pixel 28/55
Backward Adaptive <strong>Quantization</strong> (BAQ) Key idea: only encoder sees input source, if we do not want to use side channel to tell the decoder how to adapt the quantizer, we can only use quantized output to adapt the quantizer Possible solution: Observe the number of output values that falls in outer levels <strong>and</strong> inner levels If they match the assumed pdf, ∆ is good If too many values fall in outer levels, ∆ should be enlarged, otherwise, ∆ should be reduced Issue: estimation of pdf requires large observations? 29/55
Page 1 and 2: Scalar and Vector Quantization Nati
Page 3 and 4: The Quantization Problem Encoder m
Page 5 and 6: Quantization Function A quantizer
Page 7 and 8: Quantization Error If the quantiza
Page 9 and 10: Quantized Bitrate with VLC For VLC
Page 11 and 12: Uniform Quantizer All intervals ar
Page 13 and 14: Uniform Quantization of Uniform Sou
Page 15 and 16: The SNR of Quantization For n-bit
Page 17 and 18: Quantization of Non-uniform Sources
Page 19 and 20: Solving for Optimum Step Sizes Giv
Page 21 and 22: Variance Mismatch Effects (1/2) Ef
Page 23 and 24: Distribution Mismatch Effects Give
Page 25 and 26: Forward Adaptive Quantization (FAQ)
Page 27: Speech Quantization Example (2/2)
Page 31 and 32: Output Levels of 3-bit Jayant Quant
Page 33 and 34: Picking Jayant Multipliers We must
Page 35 and 36: Jayant Quantizer Performance To av
Page 37 and 38: pdf-optimized Quantization Given f
Page 39 and 40: Lloyd-Max Algorithm (2/3) Begin wi
Page 41 and 42: Example: pdf-Optimized Quantizers
Page 43 and 44: Companded Quantization (CQ) In com
Page 45 and 46: Example: CQ (2/2) The expandar fun
Page 47 and 48: Entropy Coding of Quantizer Outputs
Page 49 and 50: Why Vector Quantization (1/2)? Cor
Page 51 and 52: Vector Quantization Rule Vector qu
Page 53 and 54: The Linde-Buzo-Gray Algorithm 1. St
Page 55: Impact of Training Set The trainin

Scalar and Vector Quantization

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