Chromatic Confocal Displacement Measurment Based on Correlation Algorithm

Chromatic confocal technique application in displacement measurement is studied theoretically and experimentally. a set of refractive lenses are designed and a measurement system is established. Correlation fitting method is proposed to fit spectrum curve and find peak wavelength. Results with use of correlation fitting method are compared with Gaussian and smoothing spline fitting methods. It indicate that correlation fitting method have higher extracting accuracy of peak wavelength and smaller RMSE of linear fitting due to narrower and smoother correlation curve.

A Novel Alignment Method for Collimator Based on Laser Differential Confocal Technique

A collimator is one of the most popular optical instruments used in optical workshop and parallelism of the beams is the key technical indicator of collimator. A great deal of efforts has been expended to ensure reticle locate at the focal plane. In this paper, a new laser differential confocal collimator alignment method is proposed for precision alignment of collimators. Based on this principle an experimental setup is built up and used to align two collimators whose focal lengths are 600mm and 1000mm and f-numbers are both 10.The wave-front parallelism error of the laser differential confocal system and the tested collimator is measured by the verified experiment based on scanning penta prism method. At last some influence factors alignment precision is analyzed. Theoretical analysis and experimental results show that the alighment precision based on laser differential confocal method can reach to 0.004mm.and can be a high-efficiency approach to align collimators, especially in industry production.

An Optimal Procedure for Determining the Height Parameters of Fracture Surfaces

This paper presents an attempt to find an optimal procedure for determining the height parameters of fracture surfaces. This is a useful task that may significantly increase the reliability of topographic analyses of solids. The paper focuses on seeking an optimum number of measuring sites to ensure sufficient reliability of the resulting height parameters determined by the confocal technique. The statistical tests show that the number may be close to 25 measuring sites.