4) Representation: In this step, the system will translate
the model and form a specific code. The code for each
model is unique and consists of a set of numbers.
5) Matching: In the case that the picture is threedimensional
and corresponding to the three- dimensional
images that stored in the database, the comparisons
between the images are immediately. But the challenge
facing these systems is that most of the images stored in
database are in two-dimensional.