Shutters that open late or close early, and beams that go off, leave frames at the ends of many
sweeps with no exposure at all. Until now those frames went into the scaling like any other: on a
CCD their noise, divided by an incident flux of ~0.005, made the partials loop walk their scales
toward zero until the 50x collapse guard dropped them - or, if the loop stopped first, merged one as
noise, which delta-CC1/2 then removed with its whole 10 deg batch and reported as SWEEP_GAPS (3p85,
frames 338-359). On photon-counting detectors the blank frames fitted G = 0, escaped the guard and
were reported as merged although nothing of them was (cytc_x10sa, myob_x10sa, thau_micromax_pink,
lysoI_micromax_pink, 3p85).
TrimBlankSweepEnds (RotationScaleMerge.h) walks in from each end and clears the reflections of every
frame that
- recorded no diffraction: as many of its reflections stand more than 3 sigma below zero as above
it (a sign count, so no sigma calibration is needed and a slight background bias cannot hide the
strong reflections), and that excess is 3 sigma clear of the run's typical frame - so a crystal
too weak for one frame to show it is never trimmed; and
- had no beam: its mean background is nearer to none than to the run's typical frame. That is what
keeps a crystal leaving the beam, which also records nothing but still scatters, in the sweep
ledger as a finding (insu_I_x06da_ref, 9zm0, 9fhc, 5reo are untouched).
No stretch length: one blank frame is as blank as twenty. Partly exposed first/last frames recorded
diffraction and stay (7tcd, 7q6j, 9z72, lyso_micromax_pink). It runs on the integration outcome
before the overload count, so the merge, post-refinement and unmerged output all see the trimmed
sweep, and in --mode scale on the stored reflections. The report gives FRAMES_BLANK_START/END and a
prose line - information, no warning; the frames count as rejected. The sweep ledger looks for
degraded stretches, and reads its running medians, only between the first and last frame with data.
Delta-CC1/2: a convicted stretch that stops short of a sweep end by less than one rocking event takes
the rest, where those frames read as the stretch does (5reo: 331-396 rejected, 397-399 were left in as
a three-frame weak_diffraction range with its own warning).
Battery --only, 31 sets, tol5 f217f180a -> this commit: no space group, d_min or verdict changes;
merged statistics identical within 0.001 except 5reo (R_meas 0.236 -> 0.231, ISa 23.0 -> 23.3,
R-free 0.2013 -> 0.2004, warnings 3 -> 2). Trimmed: 3p85 0/19 (+3 empty frames; collapse-guard drops
13 -> 0), 6w4h 0/5 (guard 5 -> 0), 7rji 0/4 (delta-CC1/2 no longer removes 3406-3412, two of which
diffracted: 7 -> 0), cytc_x10sa 0/2, thau_x10sa_* 0/1-2, myob_x10sa 0/1, lyso_x10sa_strong 0/1, 8a1a
0/1, lyso_micromax_mono 1/0, lysoI_micromax_pink 2/0, thau_micromax_pink 1/0. Controls (11if, 5f6m,
6moj, 8u0i, 9fhc, 9z44, 9z72, 9zm0, 6iu6, insu_I_x06da_ref, myob_x06da_split, lyso_x06da_half_image,
thau_bl1a_4p6keV) trim nothing and are unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PXc1zD1yxHqaR1DGdCTHL4
leonarski_fandClaude Opus 5.5
1949155c12
