MEASURING SURFACE PROFILE WITH LOW-RESOLUTION DISPLACEMENT LASER SENSORS

J. Chen, R. Ward, G. Waterworth

Abstract

A new application of laser displacement sensors in measuring surface texture has been reported from industry recently. To achieve high measurement precision, laser sensors with high-resolution, which are expensive and usually means high-laser-class, are required, because if low-resolution sensors are used, the surface signal could be hidden in the internal noise of the sensor. In this paper, the mean of a number (<i>N</i>) of measurements of a specific distance between the sensor and the measured point is used to better represent the distance and reduce the internal noise. An artificial neural network has been trained to estimate a suitable value of the number <i>N</i> for a predetermined measurement precision. This way the measurement precision can be dramatically improved whilst maintaining a suitable dynamic response. The method is then further developed for continuous surface profile measurement for in-process purposes. Studies on filtering different components of surface texture using Gaussian and triangle filters have been carried out. The filtering results can be used to evaluate surface finish parameters, such as roughness and waviness.

Keywords

laser displacement sensor, surface profile, roughness, waviness, artificial neural network (ANN), filter

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IMEKO-WC-2000-TC14-P361.pdf

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IMEKO TC

TC14 - Measurement of Geometrical Quantities

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