20105ee211A_1_ComputerAssignment4Comments

20105ee211A_1_Comput - 193.83 156.64 138.06 118.96 Figure 2 Variance change of DCT coefficient and k= 0 1,… 7 3 II Huffman Coding in a Channel

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1 EE 211A Digital Image Processing I Fall Quarter, 2010 Handout 24 Instructor: John Villasenor Comments on Computer Assignment 4 I DCT-based Zonal Compression (1a) (a) (b) (c) (d) Figure 1. Zonal Compression (a) original image (b) T=1 (c) T=2 (d) T=4 The normalized mean square error(NMSE) values for T=1,2, and 4 When T=1, NMSE=1.46 When T=2, NMSE=0.90 When T=4, NMSE=0.49
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2 (1b) The variance for each of the 64 DCT coefficients l=0 l=1 l=2 l=3 l=4 l=5 l=6 l=7 k=0 40183 2662.9 978.08 502.01 306.55 237.56 188.07 133.92 k=1 6678.3 1196.1 470.38 227.41 165.48 111.65 92.522 93.763 k=2 2035.5 901.05 392.18 221.79 163.02 118.64 99.388 78.039 k=3 802.41 628.81 323.53 255.25 184.53 139.58 111.96 109.88 k=4 547.22 410.8 296.83 268.09 184.64 147.19 116.92 121.75 k=5 359.65 311.58 277.53 234.74 195.08 149.03 120.43 125.7 k=6 258.2 238.56 263.69 233.33 182.11 155.77 139.83 114.16 k=7 228.75 216.01 205.58 192.81
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Unformatted text preview: 193.83 156.64 138.06 118.96 Figure 2. Variance change of DCT coefficient ( , and k= 0, 1,…, 7) 3 II. Huffman Coding in a Channel with Errors (2b) Once a Huffman decoder loses sync, the decoder will of course continue to decode symbols. These symbols will be random, but will have the same PDF as the original symbol set (assuming the source statistics are accurately modeled). This means that common (short) codewords will be frequently generated at the decoder output, and that the “start of codeword” pointer will generally advance in small steps. In a relatively short amount of time (several codewords) this pointer will by chance fall at the correct location, and resynchronization will be re-established. Assuming no more errors, all subsequent codes will be correctly decoded. Average resync time: about 2-3 symbols Average resync time in terms of symbol offset: about 2 symbols (2c) p(symbol)...
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This note was uploaded on 04/19/2011 for the course EE 211A taught by Professor Villasenor during the Fall '10 term at UCLA.

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20105ee211A_1_Comput - 193.83 156.64 138.06 118.96 Figure 2 Variance change of DCT coefficient and k= 0 1,… 7 3 II Huffman Coding in a Channel

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