awb_gains — GFX2D isp op

Data kinds: rgbvector

Call: import fullseye as fs; fs.ledger.awb_gains(rgb, method='gray_world', percentile=99.0) (to call the implementation directly, import gfx2d; gfx2d.awb_gains(rgb, method='gray_world', percentile=99.0); from the registry, opsgfx2d.get("awb_gains"))

Usage

Estimate white-balance gains `(g_R, g_G, g_B) with g_G = 1`.

`method="gray_world": the scene averages to grey, so `g_c = mean_G /

mean_c` (Buchsbaum, 1980). method="white_patch"`: the brightest

surfaces are white, so `g_c = P_G / P_c with P` the *percentile*

(default 99, i.e. not the single hottest pixel) of each channel. Both are

closed forms; neither is right for every scene (a red wall breaks

gray-world, a coloured light breaks white-patch) and the docstring says so

rather than picking one silently. Apply with :func:rgb_apply_gains or,

on the mosaic, :func:raw_apply_gains.

Ground truth: after applying gray-world gains the three channel means are

equal to 1e-12; after white-patch gains the three percentiles are equal.

Raises `ValueError`: unknown *method*, a channel whose statistic is 0

(no gain can be defined), or a *percentile* outside `(0, 100]`.

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

raw_to_display_isppy -3.11 examples/raw_to_display_isp.py

Ops the type connects to (they accept vector as input)

rgb_apply_gains · raw_apply_gains

Same category (isp)

raw_black_level · raw_dead_pixel_mask · raw_dead_pixel_correct · lens_shading_gain · lens_shading_correct · rgb_apply_gains · raw_apply_gains · raw_demosaic_bilinear


*Provenance: gfx2d.py — GFX2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.