The pre-scan measures the gain of an SMV/marCCD detector (background variance per unit mean) but the
integrator used it only for the background clip: sigma, var_bkg, the strong-spot flag (I/sigma >= 5)
and the profile-vs-box-sum guard (10 box sigmas) all treated one ADU as one photon, so on a Saturn
(g 4.7-5.8) the guard sat at ~4.5 true sigma. The new BraggIntegrationSettings::PixelGain (set by
rugnux from the same measurement, rotation only, at max(1, g)) takes every variance the engine forms
at the gain, and Finalize converts I, sigma, bkg and var_bkg to photons, which is what the merge's
variance model (var_bkg + I) assumes. CPU and CUDA engines; Metal runs the CPU code for this. Gain 1
(every photon-counting input, ADSC/marCCD whose measured ratio is below 1, and stills) is bit-identical.
Battery --only, 12 open-arm CCD/background-dominated sets vs the base build (987e812e2), GPU:
the six Saturn sets (g 4.7-5.8) all improve - guard fallbacks 4.1-17.3% -> 1.2-6.1%,
anomalous peak height 3mc4 x1.10, 3p85 x1.02, 3r6o x1.06, 5cc8 x1.03, 5uth x1.05, 5vml x1.04;
R_meas 0.880-0.993x on all six; R_model shell-scaled better on 5/6 (5cc8 +0.0005); ISa 5uth +1.5%,
5vml +15%, 3p85 +3%, the twinned 3mc4/3r6o -5%/-1%. 6cee, 6i3j, 6v2r, 7kcn, 8v4j, 9jzo unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015CeEGgpKdfkCTJb3YNMJcu
leonarski_fandClaude Opus 5.5
46da7fb359