Matlab programs for images

Matlab program files for images

A gray-scale image is just a special graph of a function of two variables that takes values between 0 and 1. The graph is white where the function equals 1, it is black where the function is 0, and is various shades of gray for intermediate values. It can be manipulated like any other function, and you can add or average two different images, as you would add or average two functions. In practice, the image data is stored in a matrix whose entries are numbers between 0 and 1. For the examples loaded in the file images.m below, the matrices are 200 by 320. Color images are not much different. They simply have 3 functions (or matrices), one showing the red intensity, one for blue, and one for green.

General

instructions contains very simple Matlab instructions
I recommend running the Matlab image demo, called imdemo.
Note to BGSU users: the versions of Matlab available in the Scientific Computing Lab (4.2 and 5.2) do not have the image toolbox installed, and so cannot be used to run the demonstration or the program below.
However, you can run it on a UNIX machine called sigma. In the Scientific Computing Lab there are two machines on the north side of the lab from which you can log on to sigma. You can get a BG UNIX account here using only your BGNET account information.
Once logged on to sigma, you need to get the file images.m in your home directory. You can copy it from my directory using the command
```
 cp /home/25/zirbel/images.m . 
```
Now type matlab to run matlab, then type imdemo or images to see some images.

Loading images and making simple modifications

images.m loads and displays two Matlab images. It shows how to do simple modifications such as brightening, reverse video, superimposition, flipping, and blurring. It also makes a graph of the gray-scale intensity as a surface and contour graph.