Improvements in domain observation by the scanning electron microscope (SEM) type-I magnetic contrast have been achieved thanks to the use of digital image processing (DIP) system. Domain images with considerably enhanced contrast and reduced noise can be obtained. By combining image alignment with image subtraction and summation techniques, it is possible at present to separate superimposed magnetic and non-magnetic features in the images taken with a single secondary electron detector. As a consequence, detailed studies of domain structures in the cases of very weak type-I contrast and complex domain patterns, which were not possible before, can now be made. The actual problems related to the complicated mechanism of type-I magnetic contrast and its relatively low resolution are also discussed.PA CS : 75.60.-d