polar_trans_image_inv — 2D `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)

Usage

> This operator's description has not been translated yet. The original text follows as it is.

極座標→直交座標への逆変換(`cv2.warpPolar + WARP_INVERSE_MAP`)。

`polar_trans_image の逆写像で、半径 min(H,W)/2` の円盤の外側は 0 で

埋める。2026-09-02 に「cv2 が書かなかった画素が未初期化のまま返る」バグを

修正済み(戻り値でなく渡した `dst` を読んでいたため実行毎に値が変わって

いた ―― 詳細はコード内コメント)。HALCON の

`polar_trans_image_inv`（Transform an image in polar coordinates back

to Cartesian coordinates）に相当。

`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。

Detailed usage guide

• gallery2d_geometry family guide

References (sample data, literature)

• 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.

Runnable examples (verified samples that actually call this op)

• gallery2d_geometry — py -3.11 examples/gallery2d_geometry.py

Ops the type connects to (they accept `image` as input)

identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter

Same category (`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).*

polar_trans_image_inv — 2D geometry op