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hw4_002

# hw4_002 - sum up to 1 Pseudo-code for the algorithm for i =...

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HW #4 DUE: Monday, February 4, 2008 (by 5PM in the HW box) Q4 . Write a MATLAB program to reduce the effect of 1-bit quantization using “Floyd-Steinberg Dithering Algorithm”. Compare your results with uniform quantization without dithering. Comment on the differences. Use the “lena.gif” (See class website www.ece.ucsb.edu/ manj/ ece178 ) to test your program. In the “Floyd-Steinberg Dithering Algorithm” quantization error introduced at each pixel is spread over the neighboring pixels as follows: Quantization error observed at pixel ( i, j ) is diffused to the right, lower left, below and lower right pixels with the following weights (7 / 16 , 3 / 16 , 5 / 16 , 1 / 16). Here, note that the weights

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Unformatted text preview: sum up to 1. Pseudo-code for the algorithm: for i = 1 to height for j = 1 to width I2(i,j) = Q(I(i,j)); error = I(x,y)-I2(x,y); I(i,j+1) += 7 * error/16; I(i+1,j-1) += 3 * error/16; I(i+1,j) += 5 * error/16; I(i+1,j+1) += error/16; end for end for Here Q ( . ) represents inform quantization operator. In this homework, assuming that I ( i,j ) is uniformly distributed over [0 , 1], Q ( I ( i,j )) can be deﬁned as follows: 1 Q ( I ( i,j )) = ‰ 1 I ( i,j ) ≥ . 5 else Things to turn in: (a) M-ﬁle (b) Output of uniform quantization (c) Output of “Floyd-Steinberg Dithering Algorithm” (d) Comments on the diﬀerences between results. 2...
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hw4_002 - sum up to 1 Pseudo-code for the algorithm for i =...

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