Jorijn van der Graaf
48cedac3c3
The softISP AWB is pure gray world, so panning swings ColourGains with the frame average (white wall renders green when the frame is warm-dominated, dark desk renders red when cool-dominated) and the CCM, interpolated over a CT estimated from those gains, amplifies and quantizes the swings. Patch 0015 (ours, original work) adds optional per-sensor Awb tuning to the simple IPA: a piecewise-linear locus of calibrated illuminant white points in gain space that the gray-world estimate is clamped to (clampMargin), a per-stats-frame EMA on the applied gains (damping) with a fast-converge path for persistent illuminant changes, and CT interpolated from the applied gains' position along the locus - on the same scale as the tuning file's ccms table - instead of the generic estimateCCT(). Tuning files without whitePoints keep the previous behaviour exactly, so every other sensor is unaffected. imx896.yaml gains the locus from the stock tuning blob's 10-point per-illuminant AWB calibration (white points and their exactly reciprocal gain triplets, cross-validated): the 7 on-locus points as nodes, the 3 fluorescent points admitted via clampMargin 0.35. The 5000 K label is the blob's own proven anchor; 2856 K (A) is locked by the fluorescent trio projecting onto the 2856-5000 chord at ~3960 K (TL84); the rest are geometry-derived approximations. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
77 lines
3.6 KiB
YAML
77 lines
3.6 KiB
YAML
# libcamera softISP tuning for the Fairphone 6 main camera (Sony IMX896).
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#
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# CCMs extracted from the FP6 stock Android tuning blob
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# com.qti.tuned.fp6_tsp_imx896.bin (vendor_a.img, sha256 0500766f...c1a5d29f),
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# CamX cc13_ope_v2 module, tree root at 0x2709fe: 3 lux zones, 3-5 CCT
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# regions each, offsets all zero, rows sum to 1.0. This file carries the
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# BRIGHT zone (lux-index trigger 1-200) — the true-color tuning, same
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# convention as the sibling ov13b10.yaml. Note the bright zone has only
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# three CT nodes and merges D50/D65 into one 4800-6700 K region (node
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# placed at its 5750 K midpoint); the lowlight zone has proper 5000/6500 K
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# nodes but at reduced saturation (chroma-noise hiding) — see
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# chromatix/imx896-ccm-awb-extracted.txt for all 12 matrices.
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# CT nodes = the chromatix CCT trigger midpoints: 2800 (A), 4000 (TL84),
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# 5750 (merged D50/D65 region).
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#
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# blackLevel: measured on the FP6 2026-08-17 (raw RDI dark frames, phone
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# face-down, min analogue gain): 10-bit pedestal 64.0 exact (mean 63.98,
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# median 64, p1/p99 63/65) -> 4096 on the 16-bit scale. The softISP's
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# dynamic estimate ran at 48, leaving a 16-code residual the CCM amplified
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# into colour casts in dark regions.
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#
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# Awb whitePoints: the 10-point per-illuminant AWB calibration from the
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# same blob (white points @0x1c69ed, gain triplets @0x1c2dba — exact
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# reciprocals of each other, cross-validated to float precision). The
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# locus below carries the 7 on-locus points as (R gain, B gain), warm to
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# cool. The 3 fluorescent points (idx 4-6) are deliberately NOT locus
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# nodes: they sit ~0.33 gain units off the A-D50 chord (green side) and
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# would zigzag the locus; clampMargin 0.35 admits them instead. CT
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# labels: 5000 K is PROVEN (the blob's default gain + CCT anchor at
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# index 3); 2856 K (illuminant A) is locked by two independent checks —
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# sensor-typical A ratios AND the fluorescent trio projecting onto the
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# 2856-5000 chord at ~3960 K, i.e. exactly TL84; the remaining labels
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# are geometry-derived approximations (the blob stores no CCT list).
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# Same ct scale as the ccms table below. damping = per-stats-frame EMA
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# (stats run every 4th frame), ~1 s settling at 30 fps.
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#
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# PROVENANCE / LICENSE: the matrices are numeric calibration data read out
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# of the proprietary vendor blob (measured spectral response of this
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# sensor, not authored expression). Shipping decided 2026-08-17 by the
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# project owner, consistent with existing practice in this image; NOT
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# marked CC0. Durable replacement: measure our own matrices from a colour
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# chart with libcamera's tuning tooling.
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%YAML 1.1
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---
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version: 1
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algorithms:
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- BlackLevel:
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blackLevel: 4096
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- Awb:
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whitePoints:
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- { ct: 1900, gains: [ 0.878997, 4.771635 ] }
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- { ct: 2300, gains: [ 1.119141, 3.340533 ] }
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- { ct: 2856, gains: [ 1.377957, 2.769483 ] }
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- { ct: 5000, gains: [ 2.037341, 1.809127 ] }
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- { ct: 6504, gains: [ 2.367133, 1.574040 ] }
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- { ct: 7504, gains: [ 2.741927, 1.357219 ] }
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- { ct: 9500, gains: [ 4.508486, 1.012164 ] }
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clampMargin: 0.35
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damping: 0.8
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- Ccm:
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ccms:
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- ct: 2800
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ccm: [ 1.593410, -0.552769, -0.040641,
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-0.166429, 1.170414, -0.003985,
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0.004114, -0.855526, 1.851411 ]
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- ct: 4000
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ccm: [ 1.612519, -0.785270, 0.172751,
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-0.110672, 1.189965, -0.079293,
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0.091939, -0.965137, 1.873197 ]
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- ct: 5750
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ccm: [ 1.900000, -0.581250, -0.318750,
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-0.292500, 1.778126, -0.485626,
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0.014573, -0.734843, 1.720270 ]
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- Adjust:
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- Agc:
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- Af:
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...
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