cv_hough_circles — 2D `features` op

• Data kinds: image → feature

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

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

cv_hough_circles: 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

Circle detection via the Hough transform (a single scalar feature, OpenCV implementation). Detects circle centers and radii by voting, using the HOUGH_GRADIENT method that relies on edge gradient information - here, only the number of detected circles is returned (0 if none).

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

HALCON の hough_circles(Detect centers of circles for a specific radius using the Hough transform.)に相当(近似。中心座標ではなく本数のみ)。実装は `cv2.HoughCircles(_u8(v), HOUGH_GRADIENT, dp=1, minDist=10+int(a*20), param1=100, param2=20+int(b*20), minRadius=3, maxRadius=20)` —— a は検出する円同士の最小中心間距離を 10〜30 に、b は中心検出の投票しきい値 param2(小さいほど誤検出が増える)を 20〜40 に振る。param1(内部の Canny 高しきい値)と半径範囲(3〜20)は固定。

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.

cv_hough_circles 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

Same category (`features`)

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

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

cv_hough_circles — 2D features op