rescale_img — 2D geometry op

Data kinds: imageimage

Call: fullseye.apply(img, "rescale_img", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])

HALCON equivalent: zoom_image_factor (the HALCON reference is a useful guide to its meaning and parameters)

Usage

Isotropic centre-preserving rescale by `s = 0.7 + 0.6·a`, canvas kept.

> The detailed description below is the original text — the summary and the headings are translated.

`b = **補間の次数** — (0, 1, 3, 3)[min(3, int(4b))]`(0 = 最近傍、

1 = 双一次、3 = 三次スプライン)。`b=0.5 は 3 次で、b` が死んでいた頃の

既定(`ndimage` の order=3)と ビット一致する。

★2026-09-02: それまで `rescale_img / zoom_image_factor` /

`zoom_image_size` は 3 つとも同じ実装(実測: 相互の最大差 0.0 と

4.9e-14)で、3 つとも `b` を使っていなかった。3 つの役割を分けた:

• `rescale_img` — 等方倍率 1 つ + 補間次数(この関数)

• `zoom_image_factor`— 縦横 2 つの倍率(HALCON の ScaleHeight/ScaleWidth)

• `zoom_image_size` — 目標サイズ指定(出力 shape が変わる)

HALCON 名も実態に合わせて `zoom_image_sizezoom_image_factor` へ

付け替えた(この op はサイズではなく倍率で駆動するため)。

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_geometrypy -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 · affine_warp · sk_swirl · 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.