Assessment of camera models for use in planar velocimetry calibration

Kurzfassung

The performance of pinhole-based camera models for use in common light-sheet imaging arrangements is investigated on the background of application to particle image velocimetry (PIV) and Doppler global velocimetry (DGV). Calibration data obtained from translated planar calibration targets was found to yield camera attitude within 0.1° on four different test cases with object distance varying as little as 2% depending on the choice of camera model. Camera calibration using data from a single image of coplanar points is considered a viable alternative to manual triangulation of camera positions but is restricted to off-normal viewing directions. Also the influence of image mismatch and errors in viewpoint location on the reconstruction of 3-C PIV velocity data is demonstrated. It was found that the magnitude of residuals of the once-overdetermined system of equations are a viable measure of quality that is very sensitive to image geometry misalignment.