Dimensional inspecting system of thin sheet parts based on machine vision

According to the dimensional inspection,taking the thin sheet part of Head Gimbal Assembly(HGA) of the computer hard disk as an object,a line type industrial camera is used to acquire the image of the inspected part by line scanning.The calibration algorithm is proposed based on the property of the line scanning,and a contour vectorization algorithm is developed.The dimensional parameters of inspecting part are gained adopting the contour vectorization algorithm in which the image has been processed by filtering,calibration,binarization,edge detection and thinning.The parametric errors are obtained to evaluate the quality of a thin sheet part comparing the dimensional parameters obtained from scanned image to the dimensional parameters obtained from reading the design DXF file.The experimental results indicate that the precision of contour vectorization can reach to 1 pixel,the inspection accuracy can reach to 1 μm,the average inspection time of every part is 1 s and the inspecting system is feasible.