information op• Data kinds: image2d × image2d → scalar
• Call: import fullseye as fs; fs.ledger.joint_entropy(a, b, bins=64, data_range=None) (to call the implementation directly, import imgmetrics; imgmetrics.joint_entropy(a, b, bins=64, data_range=None); from the registry, opsimgmetrics.get("joint_entropy"))
Joint entropy H(A, B) [bit].
> The detailed description below is the original text — the summary and the headings are translated.
式: `-sum(p log2 p) を joint_histogram(a, b, bins, data_range)` の全セル
(`p > 0` のみ)について取る。
• `a, b: 同じ形、有限。dtype と data_range の扱いは joint_histogram`
と同じ(float は `[0, 1]` 以外なら明示必須)。
• `bins: 2 以上の整数。**値はビン数に依存する** ―― 上限は 2 log2(bins)`
(既定 64 で 12 bit)。他所の数値と比べるときは `bins と data_range` を揃える。
• 返り値: Python の `float、単位 bit、0` 以上。2 枚とも一様なら 0。
`H(A) + H(B) - H(A, B) が相互情報量(mutual_information`)。
• 失敗(`MetricContractError): 形が違う / 空 / 非有限 / bins < 2` /
`data_range` を推定できない。
位置合わせ(レジストレーション)の目的関数として、`mutual_information` /
`normalized_mutual_information` と併せて使う。
• image_difference_metrics family guide
• 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.
• image_quality_metrics — py -3.11 examples/image_quality_metrics.py
scalar as input)—
information)image_entropy · mutual_information · normalized_mutual_information · joint_histogram
*Provenance: imgmetrics.py — IMGMETRICS 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.