Performance of background-oriented schlieren with fractal-like background patterns and digital image correlation technique

The article delves into the performance of Background-Oriented Schlieren (BOS) with fractal-like background patterns and digital image correlation techniques. It discusses the significance of background patterns in monitoring density and temperature fields in fluids, highlighting the advantages of semi-random dot patterns and fractal patterns. The study introduces a new general pattern that combines the strengths of different modes and a robust image displacement estimation algorithm. The research is validated through synthetic and real-world experiments, demonstrating the advantages of the estimation algorithm and the applicability of various fractal-like backgrounds. The results show that digital image correlation proves to be the most robust method for extracting displacement information from different backgrounds, and specific patterns are suitable for different imaging environments.