How to Get pixel Intensity Values Matrix

Question

I want to get the closer look of images pixels and also the pixel value matrix (which usually ranges 255 integer values I think). Do I need Matlab, or any other program/framework? (I am a Computer Science Student)

Attached a screenshot of what exactly I want (copied from http://www.whydomath.org/node/wavlets/imagebasics.html):

Want you help, Thanks!

Answer 1

You can read an image (like this one) from disk and display it on the screen in Matlab as follows:

>> img = imread('lion.png');
>> imshow(img)

To get a closeup you just need to define the specific region you are interested in like so:

>> upper = 60;
>> lower = 100;
>> left = 40;
>> right = 80;
>> imshow(img(upper:lower, left:right))

Finally, you can also display the intensity values of a particular region of the image by simply typing:

>> row_min = 75;
>> row_max = 80;
>> col_min = 55;
>> col_max = 60;
>> img(row_min:row_max, col_min:col_max)

ans =

  159  199  180  184  181  168
  154  157  163  175  172  155
  158  135  143  156  167  149
  124  132  124  147  178  158
  126  138  123  145  178  159
  131  140  137  141  155  146