key1 - many other transform that can perform similar task...

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Distributed Multimedia System - Homework 1 sample solution. 1. Explains and illustrate the di erence between strongly periodic data and weakly f periodic data. (25%) Please see slide #8 of Lecture notes - “Multimedia elements and Characteristics”. 2. What is Nyquist criterion/theorem? (25%) It basically states that a bandlimited signal can be perfectly reconstructed if the sampling rate is at least 2 times higher than the highest frequency of the original signal. 3. List three types of image format and give a brief introduction on each type. (25%) Please see the textbook. 4. Explain the role of Discrete Cosine Transform (DCT) in image compression. (25%) DCT convert the original signal (image) from spatial domain to frequency domain. There are
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Unformatted text preview: many other transform that can perform similar task as DCT. However, one characteristic of the resulting spectrum after DCT is that the values of the low frequency components are usually much larger than those of the higher frequency components. This is the key to achieve higher compression rate As shown in Figure 7-10 on page 127 (textbook), the original signal can still be well approximated when a large portion of the higher frequency components are discarded. DCT are more suitable for compression than other transformations such as Discrete Fourier transform as it takes fewer components to approximate a signal....
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This note was uploaded on 11/30/2011 for the course CIS 6930 taught by Professor Staff during the Fall '08 term at University of Florida.

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