Updated 09 Dec 2018
Collection of functions for tracking optical distortions in a checkerboard pattern (or any other 2D periodic pattern) using 2D Fourier demodulation. Can be used for e.g. Synthetic/Background-oriented Schlieren (BOS) imaging or lens calibration. All functions are well documented and some usage examples are included.
- Robust full-field 2D distortion tracking with high dynamical range
- Can typically track displacements as small as 0.01 pixels and up to about 4 pixels (For larger displacements phase unwrapping may be required. A basic implementation for this is included.)
- Can resolve high virtual strains: up to about 0.7 px/px.
- Returns dense vector fields (one vector per pixel)
- Includes several schemes for integrating gradient fields (some of them support ROIs).
- Very fast due to extensive use of FFT
- Includes a live preview function
- Runs on GPU without modifications
More info: https://arxiv.org/abs/1712.05679
Wildeman, Sander. “Real-Time Quantitative Schlieren Imaging by Fast Fourier Demodulation of a Checkered Backdrop.” Experiments in Fluids, vol. 59, no. 6, Springer Nature, May 2018, doi:10.1007/s00348-018-2553-9.
updated citation info and extended description
updated github link
added a figure to the description