35 lines
1.7 KiB
Markdown
35 lines
1.7 KiB
Markdown
# Feature Detection
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Detect edges or corners in a surface using Canny edge detection or Harris corner detection. Outputs a feature map and a table of detected feature locations. Equivalent to Gwyddion's edge/corner detection in filters.c.
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## Inputs
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| Name | Type | Required | Description |
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|------|------|----------|-------------|
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| field | DATA_FIELD | Yes | Input surface |
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## Outputs
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| Name | Type | Description |
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|------|------|-------------|
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| result | DATA_FIELD | Feature map (binary edges or corner response) |
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| features | RECORD_TABLE | Table of detected feature statistics and locations |
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## Controls
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| Name | Type | Default | Description |
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|------|------|---------|-------------|
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| method | dropdown | canny | Detection method: canny (edges) or harris (corners) |
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| sigma | FLOAT | 1.0 | Gaussian smoothing sigma in pixels (0.1–20.0) |
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| low_threshold | FLOAT | 0.1 | Canny low hysteresis threshold (0–1) |
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| high_threshold | FLOAT | 0.2 | Canny high hysteresis threshold (0–1) |
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| harris_k | FLOAT | 0.05 | Harris detector sensitivity parameter (0.01–0.5) |
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| min_distance | INT | 5 | Minimum distance between detected corners in pixels (1–100) |
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## Notes
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- **Canny**: Multi-stage edge detector with non-maximum suppression and hysteresis thresholding. Output is a binary edge map. Reports edge pixel count and edge fraction.
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- **Harris**: Corner detector based on the structure tensor eigenvalues. Output is the corner response map. Reports up to 20 strongest corner locations with physical coordinates.
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- Increase sigma to detect larger-scale features and suppress noise.
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- For basic edge detection (Sobel, Prewitt, Laplacian), use the Edge Detect node instead.
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