sobel_dir — 2D `edges` op

• Data kinds: image → image

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

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

sobel_dir: 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

The direction of the Sobel gradient (`arctan2(dy, dx) mapped to [0,1], where 0=-pi and 1=+pi). The counterpart to sobel_amp, which returns magnitude; this operation computes the direction an edge runs in. Equivalent to HALCON's sobel_dir` (Detect edges (amplitude and direction) using the Sobel operator.) (HALCON returns amplitude and direction together, but here direction is separated out as its own op).

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

`a, b` は未使用。平坦な領域では勾配がほぼゼロベクトルになり、方向は

ノイズに支配される点に注意。

Detailed usage guide

• gallery2d_edges 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.

sobel_dir 0.40 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_edges — py -3.11 examples/gallery2d_edges.py

• poc_document_scan — py -3.11 examples/poc_document_scan.py

• poc_fiber_orientation — py -3.11 examples/poc_fiber_orientation.py

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

identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter

Same category (`edges`)

sobel_mag · prewitt_mag · roberts_mag · dog · grad_dir · log · corner_response · sk_scharr

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

sobel_dir — 2D edges op