In the rainbow schlieren apparatus, a continuously graded rainbow filter is placed in the back focal plane of the decollimating lens. Refractive-index gradients in the test section thus appear as gradations in hue rather than irradiance. A simple system is described wherein a conventional color CCD array and video digitizer are used to quantify accurately the color attributes of the resulting image, and hence the associated ray deflections. The present system provides a sensitivity comparable with that of conventional interferometry, while being simpler to implement and less sensitive to mechanical misalignment.
© 1995 Optical Society of America
Original Manuscript: July 11, 1994
Revised Manuscript: October 11, 1994
Published: July 1, 1995
Paul S. Greenberg, Robert B. Klimek, and Donald R. Buchele, "Quantitative rainbow schlieren deflectometry," Appl. Opt. 34, 3810-3825 (1995)