Comparative Analysis of Warp Function for Digital Image Correlation-Based Accurate Single-Shot 3D Shape Measurement

Abstract

Digital image correlation (DIC)-based stereo 3D shape measurement is a kind of single-shot method, which can achieve high precision and is robust to vibration as well as environment noise. The efficiency of DIC has been greatly improved with the proposal of inverse compositional Gauss-Newton (IC-GN) operators for both first-order and second-order warp functions. Without the algorithm itself, both the registration accuracy and efficiency of DIC-based stereo matching for shapes with different complexities are closely related to the selection of warp function, subset size, and convergence criteria. Understanding the similarity and difference of the impacts of prescribed subset size and convergence criteria on first-order and second-order warp functions, and how to choose a proper warp function and set optimal subset size as well as convergence criteria for different shapes are fundamental problems in realizing efficient and accurate 3D shape measurement. In this work, we present a comparative analysis of first-order and second-order warp functions for DIC-based 3D shape measurement using IC-GN algorithm. The effects of subset size and convergence criteria of first-order and second-order warp functions on the accuracy and efficiency of DIC are comparatively examined with both simulation tests and real experiments. Reference standards for the selection of warp function for different kinds of 3D shape measurement and the setting of proper convergence criteria are recommended. The effects of subset size on the measuring precision using different warp functions are also concluded.

Special Issue on Visual Sensors

“…The acquired point cloud is separated into candidate planes that are separately evaluated using a scoring strategy. Yang et al [36] presented a comparative analysis of digital image correlation based stereo 3D shape measurements.…”

Microscopic Three-Dimensional Measurement Based on Telecentric Stereo and Speckle Projection Methods

“…They are complicated and almost irreversible for the samples, and the microparticles may have a certain influence on 3D measurements. A method of projecting digital speckle patterns by means of a projector can conveniently create random features on the surface without affecting the samples, and has been applied to many macroscopic fields to achieve 3D measurements of simple shapes [ 34 ], human face [ 35 ], a Venus model [ 36 ], human body [ 37 ], a shape-complex mask [ 38 ], and different types of surfaces [ 39 , 40 ]. Whereas, this speckle projection method is rarely used in the field of microscopy.…”