Theoretical and Simulation Analysis of the Comprehensive Error in Digital Image Correlation Method
Digital image correlation(DIC)is a widely used experimental technique for measuring deformation.En-hancing measurement accuracy is a critical direction in current DIC technology research.Establishing an error theory model that comprehensively considers various error sources is crucial for clarifying the proportion and mutual cou-pling relationship of these errors in DIC methods.This paper proposes a comprehensive error theory model for DIC based on frequency domain analysis.From a system theory perspective,interpolation and noise are treated as two systems.The quantitative relationship of DIC errors is established based on the transfer functions of interpolation and noise systems.For computational convenience,this paper also presents simplified calculation methods for various parameters within the model.The proposed error model can predict the effects of various error sources in DIC meth-ods.Specifically,it can predict the systematic error caused by sub-pixel interpolation,the random error caused by image grayscale noise,and the coupling effect between systematic and random errors.To verify the effectiveness of the proposed theoretical model,extensive numerical experiments are conducted.The experimental results match well with the theoretical predictions.Theoretical and numerical simulation results indicate that the smaller speckle radii,the greater systematic errors,the higher noise levels,the greater random errors,and increase in noise levels will also lead to the increase in coupling errors.
digital image correlation(DIC)frequency domain analysiserror theorycomprehensive error
万方数据
维普
