smoothing op• Data kinds: image → image
• Call: fullseye.apply(img, "dl_aniso_diffusion", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: anisotropic_diffusion (the HALCON reference is a useful guide to its meaning and parameters)
*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.*
Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):
▸ dl_aniso_diffusion: knob a sweep (docs site)
Sweeping knob b (0.1 / 0.5 / 0.9, the other knob at its default):
▸ dl_aniso_diffusion: knob b sweep (docs site)
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ dl_aniso_diffusion: other inputs (docs site)
*The 4th column is a colour (H,W,3) input. This op handles colour without crossing channels (it does not convolve the colour channel as a third spatial axis).*
A Perona-Malik-type anisotropic diffusion filter (torch implementation; runs on the GPU if one is available).
Iterative diffusion that multiplies each of the differences in the 4 directions (up, down, left, right) by a conductance exp(-(diff/K)^2) before summing; the larger the gradient (the more edge-like the location), the weaker the diffusion, so it smooths while preserving edges. a sweeps the edge-detection threshold K over 0.02–0.22 (K = 0.02 + 0.2*a; the larger it is, the more easily diffusion crosses edges). b sweeps the number of iterations over 5–20 (iters = 5 + int(b*15)). The step size lam=0.2 is fixed. Unlike a Gaussian blur, its advantage is that it evens out only the noise without blurring edges. Corresponds to HALCON's anisotropic_diffusion (performs anisotropic diffusion of an image), but it is an approximate implementation that does not necessarily give the same result.
Border handling: wrap around to the opposite side (periodic) (measured; tools/impl2/border_probe.py).
• gallery2d_smoothing_rank 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.
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.
dl_aniso_diffusion 0.35 0.50
▸ Load this pipeline · Load & run
• gallery2d_smoothing_rank — py -3.11 examples/gallery2d_smoothing_rank.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
smoothing)gaussian · mean_box · bilateral · unsharp · sk_tv · sk_wavelet · sk_rolling_ball · sk_nlm
*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.