xmh_pftas — 2D `texture-feature` op

• Data kinds: image → feature

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

xmh_pftas: 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

Variance of the 54-dimensional PFTAS (parameter-free threshold adjacency statistics, `mahotas.features.pftas`) feature vector. A texture feature that aggregates histograms counting adjacent-pixel intensity relationships using a parameter-free threshold.

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

`a, b` は未使用。2026-09-02 実測: 54 次元の平均を使うと、正規化ヒストグラムの性質上ほぼ整数/54 の値しか取らず、12 通りの画像(4 サイズ x 3 内容)で相異なる値がわずか 2 個(事実上の定数)だった。分散にすると分布の広がりが残り画像ごとに変化するため、ここでは分散を採用している。

Detailed usage guide

• gallery2d_features 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.

xmh_pftas 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_features — py -3.11 examples/gallery2d_features.py

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

identity

Same category (`texture-feature`)

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

xmh_pftas — 2D texture-feature op