diff options
| author | Thomas White <taw@physics.org> | 2014-11-27 15:12:31 +0100 |
|---|---|---|
| committer | Thomas White <taw@physics.org> | 2014-11-27 15:12:31 +0100 |
| commit | b7a7008b8236a2035241935d1276e7113d1fc82c (patch) | |
| tree | f21a80b3332c9956c8de1ae8e4abe297351bcd5d | |
| parent | 53296b684bf2b3b37b2bb4b92e805445a0428179 (diff) | |
Fix pre-merging Poisson error calculation for low photon counts
| -rw-r--r-- | libcrystfel/src/integration.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/libcrystfel/src/integration.c b/libcrystfel/src/integration.c index 4edc0c56..edc6e7eb 100644 --- a/libcrystfel/src/integration.c +++ b/libcrystfel/src/integration.c @@ -1633,9 +1633,10 @@ static void integrate_rings_once(Reflection *refl, struct image *image, sig2_poisson = aduph * intensity; /* If intensity is within one photon of nothing, set the Poisson - * error to be one photon */ + * error to be one photon. Pretend I = 1 photon = 1*aduph, + * then sig2_posson = aduph*intensity = aduph^2. */ if ( fabs(intensity / aduph) < 1.0 ) { - sig2_poisson = aduph; + sig2_poisson = aduph * aduph; } /* If intensity is negative by more than one photon, assume that |