The surface roughness comparison specimens are used to calibrate the surface roughness of work pieces by comparison. They are widely used in machinery industry.
表面粗糙度比较样块是用比较法检查零件表面粗糙度的一种量具，在机械工业生产中得到广泛的应用。
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A nonlinear calibration method based on vanishing-point theorem is applied to calibrate the system and the image features of a free-form surface are enhanced by projecting arrays of dots.