tb_quat_normalize_image — 2D `typed` op

• Data kinds: qimage → qimage

• 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])

tb_quat_normalize_image: input → output

*The figure is the actual output on a synthetic 128×128 input. Left: input, right: output. Point clouds are drawn as a top-down scatter (brightness = z), 1-D series as a line plot, volumes as the maximum-intensity projection along z, videos as the middle frame, complex images as magnitude; return values that are not pictures are shown as the values themselves.*

*Knob a does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*

*Knob b does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*

Stages (the ops that come before → this op, left to right):

▸ tb_quat_normalize_image: stages (docs site)

On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):

▸ tb_quat_normalize_image: other inputs (docs site)

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.

Try it in Studio

The program below has been verified to run (same input as the figure). In Studio's help this block becomes buttons that load and run it on the spot.

img_to_rgb 0.50 0.50
tb_rgb_to_quaternion 0.50 0.50
tb_quat_normalize_image 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

The examples below call the underlying ledger op quat_normalize_image. This bridge op is the same implementation adapted to the fn(v, a, b) convention, so the behaviour carries over unchanged (only the call form differs).

• quaternion_monogenic — py -3.11 examples/quaternion_monogenic.py

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_project_points · tb_render_point_depth · tb_statistical_outlier_removal · tb_radius_outlier_removal · tb_voxel_grid_downsample

*Provenance: ops.py — 2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

tb_quat_normalize_image — 2D typed op