KB1 = conv2(b,Ksigma,'same')

COULD YOU PLEASE EXPLAIN THIS MATLAB CODE...ESPECIALLY THE USE OF 'same'

KB1 = conv2(b,Ksigma,'same')

Answer 1

[Wayne King]

When you convolve two matrices (images) of different sizes you get an output image that has row dimension equal to the sum of the two input matrices' row dimensions - 1. The same is true for the column dimension. The column dimension (size) of the output matrix is the sum of the column dimensions of the two input matrices - -1.

In your case, b and Ksigma are your two input matrices.

For example:

X = randn(3,3);
Y = randn(3,2);
Z = conv2(X,Y);

The output has row size 3+3-1 and column size 3+2-1

Using the 'same' option says only return the "central" part of Z in the above that matches the size of the first input image.

 Z1 = conv2(X,Y,'same');

The output has the same size as X. If you compare Z1 and Z, you'll see what is in common.