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Hit finders
Number of pixels above threshold
Total intensity above threshold
Peak finders
Two threshold algorithm
peak_finder_v1
Flood filling algorithm
...
peak_finder_v2
Local maximums search algorithm
peak_finder_v3
- makes a map of pixels with local maximums of requested rank for data ndarray and mask, pixel code in the map may have bits 0/1/2/4 standing for not-a-maximum / maximum-in-row / maximum-in-column / maximum-in-rectangular-region of radius=rank.
- for each pixel with local maximal intensity in the region defined by the rank radius counts a number of pixels with intensity above zero, total positive intensity, center of gravity coordinates and rms,
- using parameters
r0(ex.=5.0), dr(ex.=0.05)evaluates background level, rms of noise, and S/N for the pixel with maximal intensity. - makes list of peaks which pass selector with parameters set in
set_peak_selection_pars, for example
| Code Block |
|---|
alg.set_peak_selection_pars(npix_min=5, npix_max=500, amax_thr=0, atot_thr=1000, son_min=6) |
Demonstration for local maximum map
Test for 100x100 image with random normal distribution of intensities
...
| rank | 2-d region | fraction | time, ms |
|---|---|---|---|
| 1 | 3x3 | 0.1062 | 5.4 |
| 2 | 5x5 | 0.0372 | 5.2 |
| 3 | 7x7 | 0.0179 | 5.1 |
| 4 | 9x9 | 0.0104 | 5.2 |
| 5 | 11x11 | 0.0066 | 5.2 |
References
- ImgAlgos.PyAlgos - code example in Sphinx documentation
- Peak Finding - short announcement about peak finders
- Hit and Peak Finders - examples in Chris' tutorial
- Peak Finding Module - (depricated) psana module, it demonstaration examples and results
- Psana Module Catalog - (depricated) peak finding psana modules
- Psana Module Examples - (depricated) peak finding examples in psana modules
- GUI for tuning peak finding - Chun's page in development
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