Chip apparent defect detection method

The invention discloses a chip apparent defect detection method. The method comprises: an SOP chip image is shot by using a color CCD camera; extracting the circular mark of the chip and the contour and the centroid of the pin through a series of pretreatment; calculating improved environment feature vectors of the circular mark and each centroid of the pin; matching and positioning with a template image are carried out; calculating an affine transformation matrix; carrying out affine transformation on the image to obtain a template image coordinate system; and finally, judging whether the pins are lacked or not according to the improved environment vector of the circular mark. printing pixels are extracted from the printing area, the edge of the printing area is used for judging whether printing information is defective or not, a minimum circumscribed rectangle is calculated for the outline of each pin to judge whether the pins are warped upwards, warped downwards and skewed or not, and oxidation and desolde