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Given the following input-output relationship: yn = 0.6yn-1 + 0.5xn + 0.2xn-1.
Transform each row separately using an eight-point DCT. Plot the resulting 16 transform coefficients.
Obtain the two-dimensional DWHT transform by first taking the one-dimensional transform of the rows, then taking the column-by-column transform.
For the Sena image, compute the mean squared value of each of the 64 coefficients using the DWHT.
Encode the Sena image using this transform coder at rates of 0.25, 0.5, and 0.75 bits per pixel.
Investigate the issues involved in designing a set of quantization matrices. Should the quantization matrices be similar or dissimilar?
Create a program to perform the analysis and downsampling operations and another to perform the upsampling and synthesis operations for an image compression.
Encode the low-low band using a 2-bit adaptive DPCM system. Encode the low-high and high-low bands using a 1 -bit scalar quantizer.
Use the program misuquan to study the effect of mismatch between the input and assumed variances.
How do these effects change with the quantizer alphabet size and the distribution type?
Simulate the performance of this quantizer over the same range of ratio of variances as we have done for the uniform case.
For the 2 and 3 bit quantizers, compute the rate and distortion assuming that the quantizer outputs are entropy coded.
Comment on the final codebook you obtain. Plot the elements of the codebook and discuss why they ended up where they did.
Comment on the differences in the mean squared errors and the quality of the reconstructed images.
Compare the performance of a 16-dimensional pyramid vector quantizer and a 16-dimensional LBG vector quantizer for two different sources.
How does the variance of the prediction error compare with the variance of the {?n} sequence?
For each case compute the variance of the prediction error and the SNR in dB.
DPCM can also be used for encoding images. Encode the Sinan image using a one-tap predictor of the form xˆi.j = a*xi.j-1 .
DPCM-encode the Sinan, Elif, and bookshelf 1 images using a one-tap predictor and a four-level quantizer followed by a Huffman coder.
Compare the rate distortion performances using a one-tap and two-tap predictor.
Encode the sequence using the ppma algorithm and an adaptive arithmetic coder.
Encode using the Burrows-Wheeler transform and move-to-front coding.
A sequence is encoded using the Burrows-Wheeler transform. Given L = elbkkee, and index = 5.
What is the SNR for each of the reconstructions? Do the relative values reflect the difference in the perceptual quality?
If the sequence is random with P(0) = 0.8, compute the rate and distortion for M = 1, 2,4, 8, 16.