sk_autolevel — 2D `gray` op

• Data kinds: image → image

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

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

sk_autolevel: 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 auto-level. Stretches the min-to-max range of the local histogram around each pixel to fill the full 0-255 range -- an adaptive level correction that maximizes contrast per location rather than using a global tonal curve.

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

HALCON の scale_image_max(Maximum gray value spreading in the value range 0 to 255.)に相当(近似。HALCON 版は画像全体、こちらは局所窓ごと)。実装は `filters.rank.autolevel(_u8s(v), disk(1+int(a*3)))` を 255 で割ったもの —— a は円盤半径を 1〜4 に振る。b は未使用。ほぼ一様な領域ではノイズまで強く引き伸ばされる点に注意。

Detailed usage guide

• gallery2d_gray_arith 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_autolevel 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_gray_arith — py -3.11 examples/gallery2d_gray_arith.py

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

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

Same category (`gray`)

gamma · invert · scale_clip · equalize · sigmoid · clahe · sk_adapthist · sk_enhance_contrast

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

sk_autolevel — 2D gray op