typed op• Data kinds: qimage → image
• Call: fullseye.apply(img, "tb_monogenic_amplitude", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
*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.*
*The output is shown in a viridis-like pseudo-colour (dark purple = low, yellow = high) so that a field of quantities — distance, phase, orientation, depth — can be read.*
*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_monogenic_amplitude: stages (docs site)
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ tb_monogenic_amplitude: other inputs (docs site)
Local amplitude `sqrt(f^2 + R1^2 + R2^2)` of a monogenic signal. → (H, W).
The local contrast at the signal's scale, and the confidence map for
:func:monogenic_phase / :func:monogenic_orientation, which mean nothing
where this is at the rounding floor. Raw / unnormalised (a contrast is a
metric quantity), in the same spirit as `complexops.cx_magnitude`.
For a unit-contrast grating at the band centre it is exactly 1.0 (measured
spread 8.9e-16 over a 64x64 frame) and, unlike a squared oriented-filter
response, it is *isotropic*: rotating the grating does not change it.
Measured over eight grid-exact orientations the amplitude spans
`[0.99999999999999911, 1.0000000000000011]` — a total spread of 2.0e-15
across all of them, which is the isotropy claim as a number.
Raises `ValueError`: the input is not a valid quaternion field, or its
`k component is non-zero (see :func:_require_monogenic`).
Typed bridge of the quat op `monogenic_amplitude 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.
• 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 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_monogenic 0.50 0.50 tb_monogenic_amplitude 0.50 0.50
▸ Load this pipeline · Load & run
The examples below call the underlying ledger op monogenic_amplitude. 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
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
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.