r2_runlength_features — 2D `region` op

• Data kinds: region → feature

• Call: fullseye.apply(img, "r2_runlength_features", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])

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

r2_runlength_features: 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):

▸ r2_runlength_features: stages (docs site)

Usage

Region -> feature: mean length of horizontal foreground runs.

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

前景マスク(`> 0.5`)の各行を左から走査し、連続する前景画素の並び(水平ラン)の

長さをすべて集めて、その平均(画素数)を 1 つのスカラーで返す。行ごとにゼロ

埋めした行の差分でランの開始/終了を検出する。`a, b` は未使用。

返り値は `numpy.float64`。前景が無ければ 0.0。単位は画素で、画像サイズで

正規化しない(同じ形状でも解像度が 2 倍なら値も 2 倍になる)。垂直方向のランは

数えない(縦縞と横縞で値が大きく変わる、向きに依存する特徴量)。細い横線が

多い領域では値が大きく、点状ノイズが多いと 1 に近づく。ラン長の分散や

エントロピーは `r3_runlength_distribution`、短いランの除去は

`r3_eliminate_runs`。特徴量なので後段に画像 op は繋げない。

Detailed usage guide

• gallery2d_region 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
r2_runlength_features 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_region — py -3.11 examples/gallery2d_region.py

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

identity · feature_to_img

Same category (`region`)

reg_erode · reg_dilate · reg_open · reg_close · fill_holes · select_largest · remove_small · invert_region

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

r2_runlength_features — 2D region op