Polynomial Distortion
Correct nonlinear scanner distortions by applying polynomial coordinate warping independently in the x and y directions. Each axis has three polynomial coefficients controlling linear, quadratic, and cubic distortion terms. Equivalent to Gwyddion's polydistort.c module.
Inputs
| Name |
Type |
Required |
Description |
| field |
DATA_FIELD |
Yes |
Input field with scanner distortion |
Outputs
| Name |
Type |
Description |
| corrected |
DATA_FIELD |
Distortion-corrected field |
Controls
| Name |
Type |
Default |
Description |
| k1_x |
FLOAT |
0.0 |
Linear distortion coefficient for the x axis (-1.0–1.0) |
| k2_x |
FLOAT |
0.0 |
Quadratic distortion coefficient for the x axis (-1.0–1.0) |
| k3_x |
FLOAT |
0.0 |
Cubic distortion coefficient for the x axis (-1.0–1.0) |
| k1_y |
FLOAT |
0.0 |
Linear distortion coefficient for the y axis (-1.0–1.0) |
| k2_y |
FLOAT |
0.0 |
Quadratic distortion coefficient for the y axis (-1.0–1.0) |
| k3_y |
FLOAT |
0.0 |
Cubic distortion coefficient for the y axis (-1.0–1.0) |
Notes
- k1 controls linear stretching/compression, k2 controls barrel/pincushion-like quadratic distortion, and k3 controls cubic (S-shaped) distortion.
- Coefficients for x and y are independent, allowing correction of anisotropic scanner nonlinearities.
- Small values (0.01–0.1) are typical for real scanner corrections; large values produce extreme warping.
- Set all coefficients to 0.0 to pass the field through unchanged.
