geometry op• Data kinds: image → image
• Call: fullseye.apply(img, "sk_swirl", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: polar_trans_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).*
Swirl warp. A nonlinear geometric transform that rotates more strongly the closer a point is to the image center -- a distortion effect based on polar coordinate transformation.
> The detailed description below is the original text — the summary and the headings are translated.
HALCON の polar_trans_image(Transform an image to polar coordinates)に相当(近似。極座標画像そのものではなく、渦状に歪ませた直交座標画像を返す)。実装は `transform.swirl(v, strength=1+4*a, radius=30) を [0,1]` へ clip したもの —— a は渦の強さを 1〜5 に振る。渦の半径は 30 画素に固定。b は未使用。
• gallery2d_geometry 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.
sk_swirl 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_geometry — py -3.11 examples/gallery2d_geometry.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
geometry)rotate_img · rescale_img · affine_warp · mirror_image · transpose_region · rotate_image · zoom_image_factor · zoom_image_size
*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.