Feature Detection
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.
Inputs
| Name |
Type |
Required |
Description |
| field |
DATA_FIELD |
Yes |
Input surface |
Outputs
| Name |
Type |
Description |
| result |
DATA_FIELD |
Feature map (binary edges or corner response) |
| features |
RECORD_TABLE |
Table of detected feature statistics and locations |
Controls
| Name |
Type |
Default |
Description |
| method |
dropdown |
canny |
Detection method: canny (edges) or harris (corners) |
| sigma |
FLOAT |
1.0 |
Gaussian smoothing sigma in pixels (0.1–20.0) |
| low_threshold |
FLOAT |
0.1 |
Canny low hysteresis threshold (0–1) |
| high_threshold |
FLOAT |
0.2 |
Canny high hysteresis threshold (0–1) |
| harris_k |
FLOAT |
0.05 |
Harris detector sensitivity parameter (0.01–0.5) |
| min_distance |
INT |
5 |
Minimum distance between detected corners in pixels (1–100) |
Notes
- 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.
- 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.
- Increase sigma to detect larger-scale features and suppress noise.
- For basic edge detection (Sobel, Prewitt, Laplacian), use the Edge Detect node instead.
