Mie scattering theory was shown in this paper to be suitable for analyzing the forward scattered light intensity distribution of micro-sized air bubble defects in glass, shining by a monochrome laser with a wavelength of 532um. The scattered light was measured by a high definition CCD camera. The scattering process can be classified as uncorrelated single scattering according to the properties of optical media. After calculating and smoothing the gray value of split rings of picture, Chahine algorithm was applied to reverse the size of defects. This technique was accurate to within 5% for defects with radii of <50um.
In this paper, a high-accuracy calibration method for angular measurement of deformed and curved Moiré patterns, based on template matching algorithm, is presented. We report a feasible and accurate method, based on Talbot interferometry and Moiré deflectometry, to measure long focal-length lenses. Theoretical analysis indicates that the precision of this method is mainly influenced by the angle of Moiré patterns. However, it’s difficult to obtain high-accuracy angle of Moiré patterns, since the Moiré patterns derived from experiment are constantly deformed or curved. We demonstrate a method, based on template matching algorithm, to calibrate deformed and curved Moiré patterns, thus their angle can be calculated fast and accurately in sub-pixel domain. Numerical analysis and simulation prove that the method mentioned above demonstrates high precision and stability, and experiment results show that the accuracy of the long focal lengths measurement is improved obviously.