* perf(photomerge): build multi-band bands in bounded batches (#7758)
panorama::multiband built every source's Laplacian and weight pyramids
at once and kept them all until accumulation, so Photomerge's peak
memory grew with the image count (~5 GB for four 24 MP sources). Build
the bands in batches under a 2 GiB estimate (at least one image) and
add each batch before building the next. Each pixel still adds the
bands in image order, so the output is bit-identical.
Planes now move into the pyramids instead of being cloned, and the
coverage and push-pull masks are freed once used: with one image built
at a time those clones were serial passes. seam_blend shifts its ROIs
in place instead of cloning every source for the blend.
Peak during the blend: 4x24 MP 5.04 -> 2.81 GB, 8x12 MP 5.50 -> 2.61 GB,
at +5% time (2x24 MP unchanged). New example bench_multiband measures it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* perf(photomerge): let up to four 24 MP sources build their bands together
A 2 GiB band budget built every 24 MP source alone, which made the usual
2-4 image Photomerge 12-36% slower on a 32-thread desktop. The native
budget is now 5 GiB, so those still build side by side and only larger
stacks are batched. wasm32 has no threads, so it adds each band as soon
as it is built.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
