geometry op• Data kinds: image → image
• Call: fullseye.apply(img, "polar_trans_image_inv", 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_inv (the HALCON reference is a useful guide to its meaning and parameters)
Inverse transformation from polar to Cartesian coordinates (`cv2.warpPolar + WARP_INVERSE_MAP). The inverse mapping of polar_trans_image; the area outside the disk of radius min(H,W)/2 is filled with 0. A bug where "pixels not written by cv2 were returned uninitialized" was fixed on 2026-09-02 (it had been reading the passed-in dst instead of the return value, so values changed on every run — see the in-code comments for details). Corresponds to HALCON's polar_trans_image_inv` (Transform an image in polar coordinates back to Cartesian coordinates).
> The detailed description below is the original text — the summary and the headings are translated.
`a, b` は未使用 ―― 中心・半径は画像サイズから自動的に決まる。
• 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.
• 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 · sk_swirl · mirror_image · transpose_region · rotate_image · zoom_image_factor
*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.