Please explain the following code

%% watershed segmentation

hy = fspecial('sobel');

hx = hy';

Iy = imfilter(double(sout), hy, 'replicate');

Ix = imfilter(double(sout), hx, 'replicate');

gradmag = sqrt(Ix.^2 + Iy.^2);

L = watershed(gradmag);

Lrgb = label2rgb(L);

axes(handles.axes3);

imshow(Lrgb);

Answer 1

[Image Analyst]

You just need to add comments, which you could have done after reading the documentation for each function.

% Watershed segmentation
% Get the Sobel edge filter convolution kernel for one direction.
hy = fspecial('sobel');
% Get the Sobel edge filter convolution kernel for the other direction.
hx = hy';
% Get the vertical edges.
Iy = imfilter(double(sout), hy, 'replicate');
% Get the horizontal edges.
Ix = imfilter(double(sout), hx, 'replicate');
% Combine the edges to get the edges all around the objects.
gradmag = sqrt(Ix.^2 + Iy.^2);
% Evidently for this (missing) image the edges should be split apart into
% different blobs.
L = watershed(gradmag);
% Create an image where each separated blob has a different color.
Lrgb = label2rgb(L);
% Display that colorized image of the distinct blobs.
axes(handles.axes3);
imshow(Lrgb);