Research On Low Aberration Displacement Measurement Technology Based On Laser Triangulation

Measurement plays an important role in humans' daily life and industry production.In this paper,a technique of non-contact micro-displacement measurement will be proposed on the basis of laser triangulation theory.In the process of this measurement,the measurement accuracy is heavily restricted in the following aspects.Firstly,the laser which is used to detect displacements has a large divergence angle,leading the size of laser spot increasing with the measurement displacement growing.Secondly,the image spot collected by CCD distributes in large area,which makes adjacent spots superimpose together.Thirdly,the existence light noise in process of image reading makes it difficult to determine relatively accuracy spot center in the operation of spot's centroid extraction.According to the mentioned problems,several solutions are going to be proposed as followings: A micro-laser collimating system will be designed to reduce the emission of laser beam divergence angle and collimate laser beam,not only achieving the optimization of beam quality but also solving the problem that the size of laser spot increasing with displacement growing.Meanwhile,a micro-optical system is going to be designed by aberration analysis and system optimization,achieving designed optical system has a low aberration.A method will be proposed to filter noised distributed in background picture,especially around the laser spot.Then the centroid of laser spot is extracted through fitting the outline of the light spot.At the end of this paper,a comparing experiment is going to be conducted to measure certain displacement to analyze the effects of surface color on measurement accuracy.