dichromatic op• Data kinds: rgbimage → rgbimage
• Call: import fullseye as fs; fs.ledger.specular_free_transform(image_rgb, illuminant_rgb=(1.0, 1.0, 1.0)) (to call the implementation directly, import specularity; specularity.specular_free_transform(image_rgb, illuminant_rgb=(1.0, 1.0, 1.0)); from the registry, opsspecular.get("specular_free_transform"))
Project out the illuminant direction: the part of the image a highlight cannot touch. → (H, W, 3).
I - (I.G) G for the unit illuminant colour G. Under the dichromatic model the interface term is m_s * G, so it lies entirely in the removed direction and the result is invariant to any specular term whatsoever — exactly, for any lobe shape, any strength, any spatial pattern. That is the specular-invariant subspace of Mallick et al. (2005); this operator is the projection itself, with no rotation into named channels, so it stays in RGB and composes with the rest of the family.
Use it when the *shape* of the specular lobe is unknown or the surface is textured — feature matching, edge detection and correlation all work in this subspace without any of the assumptions specular_diffuse_split needs.
This is a projection, not a picture. The result loses one of three degrees of freedom (its component along G is exactly zero everywhere) and, for an image with negative values after black-level subtraction, keeps them. It is not a displayable "highlight-removed photo" and does not claim to be; for that, use specular_diffuse_split.
Raises ValueError: *image_rgb* is not a valid (H, W, 3) linear RGB image (see specular_diffuse_split); *illuminant_rgb* is not a non-zero 3-vector.
• specular_photometric family guide
• 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.
• poc_leaf_disease_area — py -3.11 examples/poc_leaf_disease_area.py
• specular_photometric — py -3.11 examples/specular_photometric.py
rgbimage as input)specular_diffuse_split · specular_coefficient_map · illuminant_from_dichromatic_planes
dichromatic)specular_diffuse_split · specular_coefficient_map · illuminant_from_dichromatic_planes
*Provenance: specularity.py — SPECULAR 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.