A hierarchical classifier for visual label identification based on binary features

Describes how, in order to control the flow of photo-cassettes in an automatic sorting system, a local photo printer laboratory has developed a unique moulded container which is able to accept and to maintain in a fixed position the different film cassette types currently in use: 24/36 roll films, pocket size, mini-pocket. The containers pass different automatic magazining stations equipped with robotic handlers. Each handler has the task to pick up a specific class of film and stack it into a magazine for further processing. The goal was the optical recognition of the film type by company brand, number of exposures and sensitivity. The only cue available for an optical classification was the printed patterns on the label. As colour was not available, the authors choose 3 types of visual greylevel features for automatic classification