texture op• Data kinds: image → image
• Call: fullseye.apply(img, "entropy_image", 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)

*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).*
An image obtained by normalizing the grayscale Shannon entropy within a circular window (`skimage.filters.rank.entropy, 8-bit quantized). A texture measure of the "spread" of gray levels within the window: low in uniform regions and high in regions where diverse gray levels mix. Corresponds to HALCON's entropy_image` (Calculate the entropy of gray values within a rectangular window) -- an approximation using a circular window here versus HALCON's rectangular window.
> The detailed description below is the original text — the summary and the headings are translated.
`a が窓の半径を 1〜4 の範囲(_rad(a))で振る。b` は未使用。skimage
が無い環境ではこの分岐は呼べない。
• gallery2d_texture_freq family guide
• 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.
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.
entropy_image 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_texture_freq — py -3.11 examples/gallery2d_texture_freq.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
texture)std_filter · gabor · sk_frangi · sk_meijering · sk_hessian · sk_gabor · sk_lbp · sk_entropy
*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.