tb_quat_normalize_image — 2D typed op

Data kinds: qimageqimage

Call: fullseye.apply(img, "tb_quat_normalize_image", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])

Usage

Per-pixel normalisation to unit modulus. → (H, W, 4).

Fail-closed on a zero pixel. A quaternion image routinely contains exact

zeros — a black pixel is `(0,0,0,0)` — so the case is not hypothetical, and

a zero quaternion has no direction to normalise towards. It is refused by

name, with the count and the first offending pixel's row and column in the

message, rather than divided by `norm + eps`: that idiom returns zero, and

a zero used as a rotor becomes the identity rotation with no exception

and no NaN to mark it. (`pose_quat.quat_normalize` did exactly that until

2026-09-01 and now fail-closes too; see :func:quat_color_rotate.)

Raises `ValueError`: any pixel has modulus 0.

Typed bridge of the quat op `quat_normalize_image into the 2-D evolution registry: the same implementation, called under the op(v, a, b) convention. This op has no tunable parameter; a and b` are unused.

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.

Runnable examples (verified samples that actually call this op)

• (none yet)

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

identity · tb_quaternion_to_rgb · tb_quat_norm · tb_quat_conjugate_image · tb_monogenic_amplitude · tb_monogenic_phase · tb_monogenic_orientation · tb_quat_color_rotate

Same category (typed)

tb_points_to_voxel · tb_estimate_point_normals · tb_iss_keypoints · tb_angle_3points · tb_project_points · tb_render_point_depth · tb_statistical_outlier_removal · tb_radius_outlier_removal


*Provenance: ops.py — 2D 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.