The Research And Implementation Of Error Calibration Algorithm For Array Automatic Optical Inspection System

The traditional Automatic Optical Inspection (AOI) system has these defects: a low accuracy and the slow detection speed. The Image Module Array AOI does not have these week points, but it emerges other new problem that theoretical precision can't be achieved in practice. And the traditional correction way is not suitable for Array AOI. Meanwhile new correction way can't achieve theoretical precision. Based on the original calibration method, we design new correction method to improve its accuracy.Against the problems which AOI baseline correction has, we design new algorithms and eliminate these errors through Instrument Correction. During the procedure, we design new methods to overcome the shortcomings. In the end the max error is only one pixel in the condition of the Instrument Correction data.Against the mechanical error, we use the Linear Correction algorithm which is based on the chi-square. This method will automatically eliminate the error. Through Instrument Correction and Linear Correction, Array AOI achieved the theoretical precision, and the paste AOI and stencil AOI have been used in product line.Against the component mounted error of the solder AOI, we design Motion Vector Correction algorithm. According to motion compensation algorithm of H.264/AVC, appropriate modifications were used to calculate the offset and angle components. For the detection of elements in general it works well.Through these algorithms, array AOI achieved the theoretical precision.