From d1ce12ce69604c6979f4ffa45e4908eb71b19c60 Mon Sep 17 00:00:00 2001 From: tlatorre Date: Mon, 13 Apr 2020 11:40:13 -0500 Subject: update find_peaks algorithm This commit updates the find peaks algorithm with several improvements which together drastically improve its ability to find Cerenkov rings: - when computing the Hough transform, instead of charge we weight each PMT hit by the probability that it is a multi-photon PMT hit - we don't subtract off previously found rings (this makes the code simpler and I don't think it previously had a huge effect) - ignore PMT hits who are within approximately 5 degrees of any previously found ring (previously we ignored all hits within the center of previously found rings) - ignore PMT hits which have a time residual of more than 10 nanoseconds to hopefully ignore more reflected and/or scattered light - switch from weighting the Hough transform by exp(-fabs(cos(theta)-1/n)/0.1) -> exp(-pow(cos(theta)-1/n,2)/0.01). I'm still not sure if this has a huge effect, but the reason I switched is that the PDF for Cerenkov light looks closer to the second form. - switch to calling quad with f = 1.0 in test-find-peaks (I still need to add this update to fit.c but will do that in a later commit). --- src/fit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/fit.c') diff --git a/src/fit.c b/src/fit.c index 0fa8766..6c6b66d 100644 --- a/src/fit.c +++ b/src/fit.c @@ -5488,7 +5488,7 @@ int fit_event2(event *ev, double *xopt, double *fmin, int *id, size_t n, double ub[3] = GTVALID; /* Find the peaks in the Hough transform of the event. */ - find_peaks(ev, pos, 100, 100, peak_theta, peak_phi, &npeaks, LEN(peak_theta), 0.1); + find_peaks(ev, pos, t0, 100, 100, peak_theta, peak_phi, &npeaks, LEN(peak_theta), 0.1); /* Don't fit more than 3 peaks for now. */ if (npeaks > 3) npeaks = 3; -- cgit