Notes written while working on HW1 by Nasser Abbasi (http://12000.org)

Course EE 203A, UCI. Digital image processing. UC Irvine, california. Fall 2004.

• Downloaded xv.exe pre-build for windows from http://www.trilon.com/xv/ (tried to build xv from course code for sygwin but errors showed up).
• Download morph page from image.vanderbilt.edu which contains raw2ras tool among others.
• Obtain the data files (raw images from UCI) and converted to ras.
• Start X by the command startxwin.sh
• To view type $ xv cat.ras

In matlab, these are some commands I used to display the raster image:

img=imread('cat.ras','ras');

colormap gray

image(img)

But the above uses gray levels of 0..1 the default in matlab, so I needed to change it to scale the values to 1..256, which is what the raster file format is. This is done like this:

>> colormap gray

>> imagesc(img,[1 256])

Now the image looks the same as from the xv command.

Now I can use matlab to finish the HW.

Wrote a function to do this problem.

>> imfinfo('cat.ras')

ans =

Filename: 'cat.ras'

FileModDate: '02-Oct-2004 12:54:49'

FileSize: 307232

Format: 'RAS'

FormatVersion: []

Width: 640

Height: 480

BitDepth: 8

ColorType: 'indexed'

FormatSignature: 1.5041e+009

Length: 307200

Type: 1

MapType: 0

MapLength: 1