Accuracy calibration is the key of high-precision chip mounter vision alignment system

affects the precision and quality of chip mounting. The traditional calibration usually requires a large number of matrix calculation to define the relation of camera coordinate

world coordinate and image coordinate . This paper presents a new calibration method based on grating

a group of data being similar to sinusoid is gotten by calculating the sum of gray-value of pixels in each column. These calculated data are elaborately showed a Lissajous figure by translation for pixel. The size mapping coefficient between the grating groove and their image pixels of the optical alignment system is calculated to realize the accuracy calibration . The result of experiments indicates that the error of the new calibration method is little

it can meet the precision needs of an automatic chip mounter vision alignment system.