gray op• Data kinds: image → image
• Call: fullseye.apply(img, "equalize", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: equ_histo_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).*
Histogram equalization (linearization). Equivalent to HALCON's `equ_histo_image` (Histogram linearization of images).
> The detailed description below is the original text — the summary and the headings are translated.
`a, b は未使用。[0,1] を 256 ビンに分けたヒストグラムの累積分布関数（CDF）を求め、各画素値をその CDF で置き換えることで、出力のヒストグラムがほぼ一様になるよう引き伸ばす。コントラストが低い（値域が狭い）画像を見やすくするのに使う。全画素が同一値だと CDF が定義できず cdf[-1]` が 0 になり、変換は事実上恒等（変化なし）になる。
• gallery2d_gray_arith 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.
equalize 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_gray_arith — py -3.11 examples/gallery2d_gray_arith.py
• poc_dehazing — py -3.11 examples/poc_dehazing.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
gray)gamma · invert · scale_clip · sigmoid · clahe · sk_adapthist · sk_enhance_contrast · sk_autolevel
*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.