leonarski_fandClaude Opus 5
a6be35ccdb
The profile is the MEAN of each bin, so a few strong reflections landing in a bin lift it exactly as a smooth powder ring does. That is the wrong quantity whenever the profile is wanted as a background rather than as a measurement of what is in the bin - the ice score being the case in point, where reading a plain profile INVERTED the metric: over 37 rotation crystals the two highest-scoring crystals had no ice at all. The adaptive spot finder already computes the right thing, a sigma-clipped per-resolution-ring background, as a byproduct of its own threshold. Where it runs, the ice score uses that. Where it does not - --no-adaptive-spots, --azint-only, and anything reading the profile the broker wrote - there was no way to get it. This adds one: azim_int_settings.sigma_clip (rugnux --azim-sigma-clip), 0 = off, minimum 2 because a tighter clip rejects a large part of a clean Gaussian bin and biases the estimate low rather than removing outliers. Two clip passes follow the plain one, matching the finder's recipe - the first pass's standard deviation is itself inflated by the peaks being removed, so one pass leaves a threshold that is still too generous. A bin with fewer than eight pixels is left alone: at the detector edge and behind the beam stop there is no spread to clip on. Both engines do it. On the GPU the accept range is computed by a small kernel and stays resident, so a clip pass is one more read of the same pixels and no round trip; the two accumulation kernels take the range as a pointer that is null on the plain pass. Measured on a JUNGFRAU rotation dataset, non-adaptive path: azimuthal integration 0.02 -> 0.06 ms per image, exactly the 3x the extra passes predict, against a 0.34 ms per-image total. Note what the result IS: the smooth background under the peaks, not the bin mean. It should not be switched on where a ring's integrated intensity is wanted - the powder-ring geometry fit reads ring peaks, and those are what a clip is designed to remove. Off by default, so nothing changes unless it is asked for. Not exposed over the REST API - that needs the generated model regenerated, which is a separate step. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
39 lines
1.7 KiB
C++
39 lines
1.7 KiB
C++
// SPDX-FileCopyrightText: 2025 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
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// SPDX-License-Identifier: GPL-3.0-only
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#include <cmath>
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#include <limits>
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#include "AzIntEngine.h"
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AzIntEngine::AzIntEngine(const AzimuthalIntegrationMapping &integration)
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: integration(integration),
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azint_bins(integration.GetBinNumber()),
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npixel(integration.GetPixelToBin().size()),
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azint_sum(integration.GetBinNumber(), 0.0f),
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azint_sum2(integration.GetBinNumber(), 0.0f),
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azint_count(integration.GetBinNumber(), 0u),
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clip_nsigma(integration.Settings().GetSigmaClip()),
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clip_lo(clip_nsigma > 0.0f ? integration.GetBinNumber() : 0),
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clip_hi(clip_nsigma > 0.0f ? integration.GetBinNumber() : 0) {}
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void AzIntEngine::UpdateClipLimits() {
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constexpr float inf = std::numeric_limits<float>::infinity();
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for (int i = 0; i < azint_bins; ++i) {
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// A handful of pixels have no spread worth the name, and clipping on it would reject most of
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// them. Leave such a bin alone - it is the detector edge and the beam stop, not signal.
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if (azint_count[i] < 8) {
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clip_lo[i] = -inf;
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clip_hi[i] = inf;
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continue;
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}
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const double n = azint_count[i];
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const double mean = azint_sum[i] / n;
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// sum2/n - mean^2 is the exact variance of what was accumulated; it can go slightly negative
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// through float cancellation on a bin whose pixels are all but identical, hence the floor.
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const double sd = std::sqrt(std::max(0.0, azint_sum2[i] / n - mean * mean));
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clip_lo[i] = static_cast<float>(mean - clip_nsigma * sd);
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clip_hi[i] = static_cast<float>(mean + clip_nsigma * sd);
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}
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}
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