scale_bar — ANNOTATE furniture op

Data kinds: image2dimage2d

Call: import annotate; annotate.scale_bar(img, length, units_per_pixel, unit='µm', xy=None, anchor='rb', color='neutral', thickness=5, margin=14, font_size=13, label=True, label_fmt='{:g}', font_path=None, scheme='okabe_ito', text_color=None) (or opsannotate.get("scale_bar"))

Usage

A scale bar in physical length. The pixel↔physical conversion is taken as an argument (never assumed).

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

バーの画素長は `round(length / units_per_pixel)` ―― これが構成的な真値で、

:mod:tests.test_annotate はこの一致を数字で確かめている。

Parameters

----------

length : float

バーが表す物理長(`unit` の単位で)。

units_per_pixel : float

1 画素が何 `unit` に相当するか。倍率ではなく分解能を渡す。

unit : str

単位の表記(`'µm', 'mm', 'px'` など)。

xy : (x,y) or None

バーの基準点。None なら `anchor 側の隅から margin` 内側。

label : bool

`"200 µm"` のラベルを併記するか。

Returns

-------

ndarray

Raises

------

ValueError

length / units_per_pixel が非正・非有限、画素長が 1 未満、

バー(とラベル)が画像に収まらない。

Detailed usage guide

figure_annotation family guide

Background guides (the physics and conventions behind this op)

dataset_conventions — 学習データセット規約の知識 — COCO / YOLO / VOC と外観検査での落とし穴

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)

annotate_gallerypy -3.11 examples/annotate_gallery.py

Ops the type connects to (they accept image2d as input)

text_box · arrow · leader_line · label_points · crosshair · legend_box · color_bar · axes_frame

Same category (furniture)

legend_box · color_bar


*Provenance: annotate.py — ANNOTATE 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.