features op• Data kinds: image → feature
• Call: fullseye.apply(img, "estimate_noise", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: estimate_noise (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).*
Robustly estimates the standard deviation σ of additive noise (`_noise_sigma: converts the MAD of the Laplacian response to a Gaussian-equivalent scale, then divides by the noise gain sqrt(20) of the 5-point Laplacian kernel). Designed to be insensitive to edge-derived outliers and pick up only the noise in flat areas (a bug in the old implementation, where "σ had no proper unit and saturated to 1.0 above σ≈0.08," was fixed on 2026-09-02 — see the _noise_sigma docstring for details). Corresponds to HALCON's estimate_noise` (Estimate the image noise from a single image.).
> The detailed description below is the original text — the summary and the headings are translated.
`a, b` は未使用。
• gallery2d_features 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.
estimate_noise 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_features — py -3.11 examples/gallery2d_features.py
feature as input)features)blob_count · area_frac · count_contours · total_length · vol_count · sk_euler · sk_entropy_feat · sk_blur_effect
*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.