sk_entropy — 2D `texture` op

• Data kinds: image → image

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

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

sk_entropy: 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

Local entropy. Computes the Shannon entropy (base-2 logarithm) of the gray-value distribution in the neighborhood (disk-shaped) around each pixel, and images it as the minimum number of bits needed to encode that location -- a measure of texture complexity/information content.

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

HALCON の entropy_image(Calculate the entropy of gray values within a rectangular window.)に相当(近似。窓形状は矩形でなく円盤)。実装は `filters.rank.entropy(_u8s(v), disk(1+int(a*3)))` を正規化したもの —— a は円盤半径を 1〜4 に振る。b は未使用。入力は内部で 8 bit 化されるため、元画像の微妙な階調差は失われる。

Detailed usage guide

• gallery2d_texture_freq 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.

sk_entropy 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_texture_freq — py -3.11 examples/gallery2d_texture_freq.py

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

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

Same category (`texture`)

std_filter · gabor · sk_frangi · sk_meijering · sk_hessian · sk_gabor · sk_lbp · sk_shape_index

*Provenance: ops.py — 2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

sk_entropy — 2D texture op