morphology op• Data kinds: image → image
• Call: fullseye.apply(img, "cv_blackhat", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: gray_bothat (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).*
Black-hat transform (OpenCV implementation). Computes "closing result minus original image" to extract only the dark features, smaller than the structuring element, that sit on a dark background (the dark counterpart of cv_tophat).
> The detailed description below is the original text — the summary and the headings are translated.
HALCON の gray_bothat(Perform a gray value bottom hat transformation on an image.)に相当。実装は `cv2.morphologyEx(v, MORPH_BLACKHAT, se) を正規化したもの、se は楕円形でサイズ 3+2*int(a*3)` —— a は構造要素サイズを 3〜9 に振る。b は未使用。
• gallery2d_morphology 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.
cv_blackhat 0.35 0.50
▸ Load this pipeline · Load & run
• gallery2d_morphology — py -3.11 examples/gallery2d_morphology.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
morphology)gerode · gdilate · gopen · gclose · tophat · bothat · morph_grad · sk_area_opening
*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.