rescale_img — 2D `geometry` op

• Data kinds: image → image

• 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)

rescale_img: 入力 → 出力

*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).*

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_size → zoom_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.

Try it in Studio

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.

rescale_img 0.50 0.50

▸ Load this pipeline · Load & run

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 · 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).*

rescale_img — 2D geometry op