Introduction
Peak finding algorithms locate regions of charge in an area detector (typically a 2-dimensional array, or a 3-dimensional array for multi-panel detectors). psana provides three peak finding algorithms that are callable from python.
Additional documentation is here and examples are here.
Algorithms
Peak Finder "V1"
This algorithm uses a "seed" threshold to start finding peaks, and then a lower "neighbor" threshold to add additional pixels to the peak. A surrounding region can be specified as a background region to evaluate signal-over-noise.
Peak Finder "V2"
This is similar to the "V1" algorithm, but uses a single low threshold, and then joins regions of contiguous pixels using a "flood-fill" algorithm. A surrounding region can be specified as a background region to evaluate signal-over-noise.
Peak Finder "V3"
This algorithm finds the largest pixel in a square region set by a "rank" parameter. The square extends from maxPixel-rank to maxPixel+rank in both the x/y directions. The total amplitude is evaluated as the sum of all pixels inside the square that are larger than zero. The noise can also be evaluated in user-specified ring around the peak. The user will typically reduce the number of peaks returned from this algorithm by applying cuts to signal levels or signal-over-noise.
Overview
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