Application of oil-film interferometry image post-processing technology based on MATLAB

The image post-processing technology based on MATLAB was applied in oil-film interferometry to calculate the skin friction coefficient. This method can recognize the bright and dark fringes by the algorithm based on standard deviation, which is efficient and robust. Furthermore, it can process low-quality images and extract fringe spacing by converted grayscale image and the proper sliding window can catch the discrete objectives precisely by multiple selected windows. In addition, the calculation window size can adjust automatically, which improved the robustness of the algorithm greatly. By comparing the experimental results with the numerical results, it is proved that the method of post-processing based on MATLAB can accurately measure the skin friction in hypersonic flow.