Noise analysis in outdoor dynamic speckle measurement

TL;DR

This paper evaluates the robustness of the outdoor dynamic speckle measurement method under environmental noise, demonstrating its feasibility through simulations and real experiments with noise mitigation techniques.

Contribution

It analyzes the effectiveness of the dynamic speckle method in noisy outdoor conditions and explores normalized estimates for non-uniform illumination.

Findings

Good agreement between ground truth and noisy data maps

Feasibility of outdoor measurement confirmed

Normalized estimates improve accuracy

Abstract

Dynamic speckle method is an effective tool for estimation of speed of processes. Speed distribution is encoded in a map built by statistical pointwise processing of time-correlated speckle patterns. For industrial inspection,the outdoor noisy measurement is required. The paper analyzes efficiency of the dynamic speckle method in the presence of environmental noise as phase fluctuations due to lack of vibration isolation and shot noise due to ambient light. Usage of normalized estimates for the case of non-uniform laser illumination is studied. Feasibility of the outdoor measurement has been proven by numerical simulationsof noisy image capture and real experiments with test objects. Good agreement has been demonstrated both in simulation and experiment between the ground truth map and the maps extracted from noisy data.