how does code work in identify the images?

inverse_binary=not(handles.bw);

[handles.L handles.Num_object]=bwlabel(inverse_binary);

[Rik]

Did you read the documentation for these two functions?

Answer 1

[Image Analyst]

See my Image Segmentation Tutorial.

Image Analyst's File Exchange

It goes over questions like that in a well commented script using a built-in MATLAB demo image.