Improving the performance of optical systems for a tool presetter

A tool presetter is a non-contact precision measuring instrument that is used to measure the parameters of NC cutting tools rapidly and precisely. An optical system is its kernel component of non-contact measurement which directly influences measuring accuracy. It is a limited luxury to increase the measuring accuracy only through the use of a better optical system, it is more effective to increase the measuring accuracy through software and algorithms. The main algorithms that influence the measuring accuracy of an optical system include: image edge detection algorithm and image positioning algorithm. This paper provides analysis of these and puts forth two newly developed algorithms for improving the measuring accuracy of a tool presetter. The first algorithm is image edge detection based on subpixels that increases the edge positioning accuracy more than ten times. The second one is uniformity compensation for whole view measurement that is able to capture accurate real pixel size making image movement more precise, which further increases the measuring accuracy. These two algorithms are tested in CoVis software and the results demonstrate that the total measuring accuracy of the tool presetter is dramatically improved to 2 µm.