std_filter — 2D `texture` op

• Data kinds: image → image

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

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

Usage

Standard deviation within a local window (an indicator of texture coarseness). Equivalent to HALCON's `deviation_image` (Calculate the standard deviation of gray values within rectangular windows.).

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

`a が窓サイズを 3,5,7,9（_k(a)）に振る。b は未使用。E[v²]-E[v]² を窓ごとに求めて平方根を取り（負の丸め誤差は 0 にクランプ）、_norm` で正規化する。値が大きいほどその窓内の階調が激しく変化している（テクスチャがある/エッジが多い）ことを示す。

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.

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`)

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

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

std_filter — 2D texture op