log — 2D edges op

Data kinds: imageimage

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

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

log: 入力 → 出力

*The figure is the real output on a synthetic 128×128 input. Left: input, right: output (a non-image return value is shown as the value itself).*

Usage

Laplacian of Gaussian (LoG) filter. Equivalent to HALCON's `laplace_of_gauss` (LoG-Operator (Laplace of Gaussian).).

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

`a がガウシアンの標準偏差 σ を 0.5〜3.0 に振る。b は未使用。scipy.ndimage.gaussian_laplace の絶対値を _norm` で正規化する(符号を捨てているため、暗背景上の明斑点と明背景上の暗斑点を区別できない)。ブロブ(斑点状構造)検出やエッジ検出に使う。

Detailed usage guide

gallery2d_edges 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.

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.

log 0.40 0.50

▸ Load this pipeline  ·  Load & run

Runnable examples (verified samples that actually call this op)

gallery2d_edgespy -3.11 examples/gallery2d_edges.py

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

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

Same category (edges)

sobel_mag · prewitt_mag · roberts_mag · dog · grad_dir · corner_response · sk_scharr · sk_farid


*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.