height_width_ratio — 2D `features` op

• Data kinds: region → feature

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

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

height_width_ratio: input → output

*The figure is the actual output on a synthetic 128×128 input. Left: input, right: output. Point clouds are drawn as a top-down scatter (brightness = z), 1-D series as a line plot, volumes as the maximum-intensity projection along z, videos as the middle frame, complex images as magnitude; return values that are not pictures are shown as the values themselves.*

*Knob a does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*

*Knob b does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*

Stages (the ops that come before → this op, left to right):

▸ height_width_ratio: stages (docs site)

Usage

Aspect ratio `height / width of the axis-parallel surrounding rectangle. There is no upper bound — a tall region exceeds 1 (160x4 gives 40.0). It is the **same quantity as the Ratio** among the three values HALCON's height_width_ratio` (Compute the width, height, and aspect ratio of the surrounding rectangle parallel to the coordinate axes.) returns (Height and Width are pixel lengths and are not returned — see docs/KNOWN_ISSUES.md §51).

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

★2026-09-26 まで `min(1, 高さ/幅)` で切っていたので、**縦長の対象が全部

1.0** になっていた(60x20 で 1.0、真値 3.0)。横長は正しく出るので、

向きが変わった瞬間に情報が消える。飽和は説明文に「仕様」として書かれて

いたが、値域 [0,1] は feature の契約ではなく、潰す理由が無かった ――

`docs/hardening/features-saturated-at-one.md`。

`a, b` は未使用。

Detailed usage guide

• gallery2d_features 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.

threshold 0.50 0.50
height_width_ratio 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_features — py -3.11 examples/gallery2d_features.py

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

identity · feature_to_img

Same category (`features`)

effective_bit_depth · blob_count · area_frac · count_contours · total_length · vol_count · sk_euler · sk_entropy_feat

*Provenance: ops.py — 2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

height_width_ratio — 2D features op