Adding a comment for possible update of Poisson variance computation …

…using the average dark current.
kmacdonald-stsci · Apr 9, 2024 · 6068890 · 6068890
1 parent 5771276
commit 6068890
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/src/stcal/ramp_fitting/src/slope_fitter.c b/src/stcal/ramp_fitting/src/slope_fitter.c
@@ -2591,6 +2591,8 @@ ramp_fit_pixel_integration_fit_slope_seg_len1(
     seg->slope = pr->data[idx] / timing;
 
     pden = (timing * pr->gain);
+    /* XXX PR # 254.  Is there a JP ticket for this? */
+    /* seg->var_p = (pr->median_rate pr->dcurrent) / pden; */
     seg->var_p = pr->median_rate / pden + pr->dcurrent;
 
     /* Segment read noise variance */
@@ -2636,6 +2638,8 @@ ramp_fit_pixel_integration_fit_slope_seg_len2(
     /* Segment Poisson variance */
     if (pr->median_rate > 0.) {
         pden = (rd->group_time * pr->gain);
+        /* XXX PR # 254.  Is there a JP ticket for this? */
+        /* seg->var_p = (pr->median_rate pr->dcurrent) / pden; */
         seg->var_p = pr->median_rate / pden + pr->dcurrent;
     } else {
         seg->var_p = pr->dcurrent;
@@ -2797,6 +2801,8 @@ ramp_fit_pixel_integration_fit_slope_seg_default_weighted_seg(
     /* Segment Poisson variance */
     if (pr->median_rate > 0.) {
         pden = (rd->group_time * pr->gain * (seglen - 1.));
+        /* XXX PR # 254.  Is there a JP ticket for this? */
+        /* seg->var_p = (pr->median_rate pr->dcurrent) / pden; */
         seg->var_p = pr->median_rate / pden + pr->dcurrent;
     } else {
         seg->var_p = pr->dcurrent;