tb_landmark_asymmetry — 2D typed op

• Data kinds: points → signal

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

tb_landmark_asymmetry: 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_landmark_asymmetry: stages (docs site)

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

▸ tb_landmark_asymmetry: other inputs (docs site)

Usage

Signed asymmetry for each left/right pair. → (M,).

For each pair, mirror one point across the plane, compare it with the other, and return the difference along the plane normal. The sign is "positive if the right side is outward" (mirror_plane_from_pairs orients the normal that way). Do not collapse it to an absolute value —— which side, left or right, protrudes means something different both in the clinic and in inspection.

pairs=None / plane=None both take the same defaults as mirror_plane_from_pairs (first-half/second-half pairs, and the midsagittal plane derived from those pairs). If you omit the plane, the plane itself is determined from the same pairs, so you end up "measuring the deviation from the plane with the material that fixed the plane" —— the left-right difference can still be measured (by definition the midpoint leans to neither side), but if the plane can be fixed from an independent source of information, passing it is stronger.

The shapestat op landmark_asymmetry, bridged into the 2-D evolution registry. The implementation is the same; only the calling convention is adapted to op(v, a, b). This op has no tuning knobs; neither a nor b is used.

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_points 0.50 0.50
tb_landmark_asymmetry 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 landmark_asymmetry. 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).

• shapestat_landmark_tour — py -3.11 examples/shapestat_landmark_tour.py

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

identity · tb_create_funct_1d_array · tb_smooth_funct_1d_gauss · tb_smooth_funct_1d_mean · tb_derivate_funct_1d · tb_integrate_funct_1d · tb_zero_crossings_funct_1d · tb_abs_funct_1d

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).*

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