smoothing op• Data kinds: image → image
• Call: fullseye.apply(img, "cv_sharpen", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: emphasize (the HALCON reference is a useful guide to its meaning and parameters)
*The figure is the actual output on a synthetic 128×128 input. Left: input, right: output. Point clouds are drawn as a top-down scatter (brightness = z), 1-D series as a line plot, volumes as the maximum-intensity projection along z, videos as the middle frame, complex images as magnitude; return values that are not pictures are shown as the values themselves.*
Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):
▸ cv_sharpen: knob a sweep (docs site)
*Knob b does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ cv_sharpen: other inputs (docs site)
*The 4th column is a colour (H,W,3) input. This op handles colour without crossing channels (it does not convolve the colour channel as a third spatial axis).*
An unsharp-mask-like sharpening filter (3x3 kernel convolution, OpenCV implementation). Convolves with a kernel whose center is `1+4a and whose top/bottom/left/right neighbors are -a` (at a=0 this is the identity kernel = no change; the larger a is, the stronger the discrete-Laplacian-like high-frequency boost), lifting the contrast near edges.
> The detailed description below is the original text — the summary and the headings are translated.
HALCON の emphasize(Enhance contrast of the image.)に相当(近似)。実装は `cv2.filter2D(v, kernel) を [0,1]` へ clip したもの —— a はカーネルの強さ(鮮鋭化の度合い)を 0〜1 に振る。b は未使用。
Border handling: mirror without repeating the edge pixel (d c b | a b c d — OpenCV's `BORDER_REFLECT_101) (measured; tools/impl2/border_probe.py`).
• gallery2d_smoothing_rank 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_sharpen 0.35 0.50
▸ Load this pipeline · Load & run
• gallery2d_smoothing_rank — py -3.11 examples/gallery2d_smoothing_rank.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
smoothing)gaussian · mean_box · bilateral · unsharp · sk_tv · sk_wavelet · sk_rolling_ball · sk_nlm
*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.