key difference between the books is that Digital Image Processing (DIP) deals primarily with the
theoretical foundation of digital image processing, while Digital Image
Processing Using MATLAB (DIPUM) is a book whose main focus is the use of
MATLAB for image processing. The DIPUM book covers essentially the
same topics as DIP, but the theoretical treatment is not as detailed. Some
instructors prefer to fill in the theoretical details in class in favor of
having available a book with a strong emphasis on implementation.