A new approach for measurement of wire diameter by optical diffraction

摘要

A new approach for measurement of wire diameter lying in the range of 200 to 450μ is proposed and demonstrated. The approach is based on evaluation of phase-correlation based similarity measure for two identical order fringes of a diffraction pattern. Diameter of wires is estimated by determining separation between identical order fringes. Robustness of the approach to noise is enhanced by using Gaussian and singular value decomposition based filtering. Implementation of the method with an off-the-shelf digital photo camera for acquiring experimental data from steel wires and thin slits have demonstrated an accuracy far better than 0.5% of dimension.