A quantitative reconstruction method for background-oriented schlieren by reducing the weight matrix

Abstract

In the background-oriented schlieren (BOS), the 3D deflection caused by refractive index gradient is projected onto the camera imaging plane with one dimension leaved out, and sensed as a 2D displacement using the images of background with and without the flow field. In the reconstruction, instead of decomposing the 2D displacement as in previous studies, we project the elements in the BOS weight matrix to 2D. By doing so, this technique reduces memory usage and improves the reconstruction time as the number of rows in the weight matrix is decreased by a third, and the errors produced in 2D displacement decomposition are avoided.