Page Comparison

• Select matrix and copy

• In MATLAB, paste into variable ("a" in the example below):

First type

>> a= [

then paste (Ctrl^V)

then close bracket, and Enter ]

• Create the image

>> figure

>> imshow (a)

(or on the same line)

>> figure, imshow(a)

• Zoom in to see

Color

If the image is intensities, imshow displays a grayscale image. To display in another color,

1) convert to index

2) imshow with colormap

Converting to index just means convert to numbers into the colormap.

>> num_colorsinmap = 256;

>> a_indexed = round( a * 255 );

• Works for values between 0 and 1; scales 0 to bottom of coloramp, and 1 to top

>> cmap = hot( num_colorsinmap );

• For other colormap options, hype >> help colormap 
• Examples include hot, hsv, jet, and with CSPM you get jettop, jetbot

>> figure, imshow(a_indexed, cmap)

You could also do this in one line:

>> figure, imshow( round(a*255), hot(256) )

Increase resolution (smooth)

Use the interp2 function to resample at a factor of the original resolution.

>> res_factor = 4;

>> a_res = interp2( a, res_factor );

>> a_res_indexed = round( a_res * 255 );

>> figure, imshow(a_res_indexed, cmap)

Example script

Use the following MATLAB script to create figures. Load the data into "a" first, download the file into a folder, and open it in matlab. Change the parameters and run.

You can create these:

Image Added or Image AddedorImage Added