The application of tiny triplet finder (TTF) in BTeV pixel trigger

We describe a track segment recognition scheme called the Tiny Triplet Finder (TTF) that involves grouping of three hits satisfying a constraint such as forming of a straight line. The TTF performs this O(n³) function in O(n) time, where n is number of hits in each detector plane. The word "tiny" reflects the fact that the FPGA resource usage is small. The number of logic elements needed for the TTF is O(Nlog(N)), where N is the number of bins in the coordinate considered, which for large N, is significantly smaller than O(N²) needed for typical implementations of similar functions. The TTF is also suitable for software implementations as well as many other pattern recognition problems.