diff options
| -rw-r--r-- | libcrystfel/src/integration.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/libcrystfel/src/integration.c b/libcrystfel/src/integration.c index c922f703..3d8258c1 100644 --- a/libcrystfel/src/integration.c +++ b/libcrystfel/src/integration.c @@ -1487,6 +1487,11 @@ static int integrate_rings_once(Reflection *refl, struct image *image, * appropriate size */ if ( intensity < -aduph ) { sig2_poisson = -aduph*intensity; + } else if ( intensity < 0.0 ) { + /* If the intensity is negative (by less than one + * photon), assume the reflection is very weak and + * therefore has a Poisson error of one photon. */ + sig2_poisson = aduph; } sigma = sqrt(sig2_poisson + bx->m*sig2_bg); |