The stills scaling/merging path (ScaleOnTheFly + MergeOnTheFly) had no
correction surfaces, whereas rotation fits decay/absorption/modulation inside
RotationScaleMerge. Serial stills hammer the same detector regions shot after
shot, so a detector-plane (flat-field) systematic is at least as well
determined there as in rotation - it just had no home.
Add MergeOnTheFly::RefineModulation: a 16x16 multiplicative surface over the
predicted detector position, fit against the merged reference and folded into
each reflection's image_scale_corr before the error model and the merge. It
mirrors RotationScaleMerge::ApplyCellSurface - alternating per-cell fit with a
den-weighted geometric-mean gauge (never drifts the overall scale) and
Tikhonov pull to 1 - and is cross-validated the same way: fit the surface on
even images, score the held-out odd equivalents by a sigma-independent
R-meas-like agreement (a fractional metric a sigma-reshaping surface cannot
game), and apply the full-data surface only if the held-out gain clears a
margin. A no-op when the systematic is absent or the data too sparse (< 8 obs
per cell), so it is safe to leave off by default and opt in.
Wired through ScalingSettings::StillsModulation and rugnux --stills-modulation
(default off), in both the full-analysis and --scale paths. On a 17 MP
JUNGFRAU serial set the surface cross-validates with a large held-out gain,
confirming a real detector-plane systematic; whether it improves the merged
data quality is under evaluation.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
leonarski_fandClaude Opus 4.8
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