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Unformatted text preview: # 20 ECE 253a Digital Image Processing Pamela Cosman 11/23/10 HOMEWORK 6 Due Friday Dec 3 in class 1. JPEG quality levels: This is a simple exercise intended just to give you a feel for the quality versus bit rate performance of JPEG. Read the images aerial4.tif and xray.tif into Matlab using imread. Matlab allows you to control the quality level (and therefore the bit rate) of the JPEG image that you are writing out. Try writing out the image with terrible quality (quality level = 1) and with excellent quality (quality = 100) and with several values in between. If your image is anmed aerial, the imwrite command to get quality level 1 would be: imwrite(aerial,’aer1.jpg’,’jpg’,’quality’,1); For each image, make a plot of MSE versus bit rate, and a plot of PSNR versus bit rate. That is, we want a plot that shows the MSE between the JPEG compressed image and the original image, versus the bit rate of the JPEG compression. To get the MSE, read the JPEG image back into Matlab, and compute the MSE between it and the original image. To get the bit rate, look at the file size of the jpeg file that Matlab created....
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This note was uploaded on 01/15/2012 for the course ECE ece253A taught by Professor Cosman during the Fall '11 term at UCSD.
- Fall '11
- Image processing