Hierarchical correlation for track finding

In this paper a method to perform a fast reconstruction of straight tracks is presented. The algorithm developed is suitable for hardware implementation. The tracks are correlated with masks generated with the aid of the Walsh transform. It is shown that matching with a predefined mask allows the evaluation of the track slope. This correlation is combined with the multiresolution technique for a fast identification of the slope. A hardware correlator that analyses an image of 10×800 pixels in less than 500 μs has been set up for an experiment at the Gran Sasso laboratory in Italy.