Printed circuit board welding spot defect detection method based on digital image processing

The invention discloses a printed circuit board welding spot defect detection method based on digital image processing. The method comprises the following steps: step 1, acquiring a template picture and an original picture of a printed circuit board to be detected; 2, preprocessing the template picture and the picture to be detected; step 3, carrying out particle swarm optimization (PSO) optimized OTSU threshold segmentation on the preprocessed template picture and the picture to be tested; step 4, carrying out image registration of an FLANN optimized SURF algorithm on the to-be-detected image after threshold segmentation according to the template image; step 5, using a difference image method to make a difference between the registered to-be-detected picture and the template picture to obtain a difference image; step 6, carrying out morphological processing such as binaryzation, opening operation of first corrosion and then expansion on the difference image, and finally positioning a defective position; the