Assessment and application of optical flow in background-oriented schlieren for compressible flows

Abstract Optical flow provides an opportunity to elevate the resolution and sensitivity of deflection sensing in background-oriented schlieren (BOS). Despite extensive relevant literature within field computer vision, there is a lack proper quantification its abilities limitations with regard state-of-the-art BOS experiments. Thus, this study performs assessment accuracy limits different scenarios utilizing background patterns generated random dot wavelet noise distributions. Accordingly, synthetic over theoretically Prandtl–Meyer expansion fan conducted variations introduced operational parameters optical flow. A clear superiority resolvable range density gradient amplitudes cross-correlation demonstrated. Moreover, experimental supersonic features multiple wind tunnel models performed. The influence constraints, uncertainties related application comparative performance against block-matching counterpart characterized. Graphical abstract