Correcting method for inspection frame in AOI (Automatic Optical Inspection) of printed circuit board

The invention relates to a correcting method for an inspection frame in AOI (Automatic Optical Inspection) of a printed circuit board. The correcting method comprises the following steps: firstly, starting a light source and starting a CCD (Charge Coupled Device) camera to shoot the printed circuit board, wherein the CCD accumulates charges in corresponding proportion according to the intensity of light, the charges accumulated by each pixel move outwards one by one under the control of a video time sequence and form a video signal for outputting after being subjected to filtering and amplification processing, and an image processing system establishes a current image according to the video signal; secondly, selecting at least two drilling holes to serve as reference holes from the current image, comparing the actual coordinates of the reference holes with the standard coordinates of the reference holes in the system, calculating the offset amount and the offset direction of each reference hole, and substituting the offset amounts and the offset directions of all reference holes into a function to calculate a correction value and a correction direction; thirdly, moving a Solder frame according to the correction value and the correction direction and then positioning to form the inspection frame after the current image is framed by the Solder frame according to the standard coordinates in the system. According to the correcting method, the accuracy of AOI inspection is improved.