isotropic_diffusion — 2D smoothing op

Data kinds: imageimage

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

HALCON equivalent: isotropic_diffusion (the HALCON reference is a useful guide to its meaning and parameters)

Usage

The implementation is a simple Gaussian blur (`gaussian_filter, sigma 0.5+2.5*a). Since the solution of the isotropic diffusion equation is mathematically equivalent to convolution with a Gaussian kernel, this approximation is theoretically valid (it has no edge-preserving effect like anisotropic diffusion, and smooths uniformly regardless of direction). Corresponds to HALCON's isotropic_diffusion` (Perform an isotropic diffusion of an image).

> The detailed description below is the original text — the summary and the headings are translated.

`a がシグマ(拡散時間に相当)を 0.5〜3.0 の範囲で振る。b` は未使用。

Detailed usage guide

gallery2d_smoothing_rank family guide

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.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

gallery2d_smoothing_rankpy -3.11 examples/gallery2d_smoothing_rank.py

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

identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter

Same category (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.