Abstract
A Background Oriented Schlieren (BOS) technique using a periodic background image containing multiple frequency components has been developed by the authors, and "phase reversal problem", which is specific problem for BOS method using a periodic pattern, has been resolved. But the displacement detection by the method was restricted to one direction. In this study, we have extended this method to detect two-dimensional displacement using a colored grid in the background. We have evaluated its effectiveness by making visualization of supersonic free jet.
