ncc_locate — 2D matching op

Data kinds: imagematch

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

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

Usage

Finds the best position using template matching based on normalized cross-correlation (NCC). Equivalent to HALCON's `find_ncc_model` (Find the best matches of an NCC model in an image.).

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

`a, b は未使用——テンプレートは引数ではなく set_match_template でスレッドローカルな _MATCH_CTX に事前登録しておく(マッチング系 op 共通の作法、_MatchCtx の docstring 参照)。_ncc_map(NCC 相関マップ、Lewis 1995 の定義で [-1,1])を計算し、その最大値の位置を [相関値, y, x] で返す。テンプレート未設定、または入力が 2 次元画像でない場合は [0,0,0](no-match)を返す——fail-closed。回転・スケール変化には非対応(_shape_locate` は回転を扱う)。

Detailed usage guide

gallery2d_contour_measure 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_contour_measurepy -3.11 examples/gallery2d_contour_measure.py

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

identity

Same category (matching)

shape_locate


*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.