DCT Row 256 of lenna absolute dct values
利用DCT轉換前後的範例 Row 256 of lenna absolute dct values of lenna row 256 2500. 00 2000. 00 160. 00 1500. 00 120. 00 1000. 00 80. 00 40. 00 500. 00 200. 00 400. 00 600. 00 4
10. 3. 5 Walsh-Hadamard 轉換(WHT) n Walsh-Hadamard 轉換 n 定義更大的Hadamard矩陣之規則 ，其中H 2 n為 2× 2的Hadamard矩陣 18
10. 3. 5 Walsh-Hadamard 轉換(WHT) 19
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10. 5. 1 JPEG 基本系統 Input image Binary bit stream output image Blocking DCT Entropy coder Zigzag Scan 1 -D sequencing Entropy decoder Inverse Zigzag Scan Blocking Integration IDCT Thresholder Quantizer Dequantizer Thresholder compensator 24
10. 5. 1 JPEG 基本系統 n DCT/IDCT formula n Separable n n BASIS 2 D(i, j; u, v) = BASIS 1 D(i; U) BASSIS 1 D(j ; v) process row, then column. 25
10. 5. 1 JPEG 基本系統 n Quantization T+3 Q/2 T+Q/2 -T-2 Q -T-Q -T T T+Q T+2 Q -T-Q/2 -T-3 Q/2 T=deadzone threshold Q=quantizer step size 26
10. 5. 2 JPEG DCT之一例 32
10. 5. 2 JPEG DCT之一例 n 79 0 -2 -1 -1 -1 0 0 -1 EOB 34
Results 786488 bytes 23116 bytes, Cr=34. 0 38
Results 786488 bytes 33079 bytes, Cr=23. 78 39
Results 786488 bytes 49746 bytes, Cr=15. 80 40
Results 786488 bytes 26614 bytes, Cr=29. 55 41
Results 786488 bytes 25485 bytes, Cr=30. 86 42
JPEG Lossless Coding n DPCM 0 1 2 Prediction No A B 3 4 5 6 7 C A+B-C A-(B-C)/2 B-(A-C)/2 (A+B)/2 43
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