The stamp classification cannot be done with the machine learning technologies as the image recognition is particularly difficult if images are not taken in specific light conditions and because the number of available images for training the neural network was too small. In any case, the classification may be done using the information that can be directly read by the user: the visually recognisable letters on the sherd. 

As for the previous classification tools, the first step for stamp classification is the acquisition of the stamp image from a gallery or directly with the camera as shown in the picture below.