White Light Interferometry For Fast Areal Surface Measurement Based On GPGPU

Nowadays, products is becoming smaller and smaller. Thus, high-accuracy machining is rather important than ever before. And the first step to ensure the high accuracy is monitoring the surface appearance while machining.Of course, there are all kinds of methods to do a surface measurement. But due to the advantages of high-precision, non-contact and quantitative analysis, an optical method is always preferred. As known to all of us, white light interferometry is an extremely powerful and useful tool for surface measurement. Rough surface and step surface could also be tested by white light interferometry. But if we want white light interferometry to be used for online measurement, there are two questions should be concerned. Firstly, it is really hard to find zero OPD position; secondly, based on white light interferometry tens to hundreds of images should be processed. It's really time-consuming compared with some other laser interferometry.GPU, which stands for graphic processing unit, has evolved into a highly parallel, multithreaded, manycore processor with tremendous computational horse power and very high memory bandwidth. And recently it's not only used in image rendering, but also used in general purpose computing.In this paper, based on the research of all kinds of common wavelength scanning interferometry and white light interferometry, a novel fast white light interferometry measurement system is proposed, which could reduce the measurement time from minutes to seconds.