The method of defect inspection was proposed aiming at the glass defects during float glass production.The transmissive optical path was designed

gratings' two-period sinusoidal light intensity were generated on the testing glass based on dual CCFL

and linear CCD collected the defects image with uniform velocity.The two-threshold segmentation algorithm was used for the binary processing of the defects image

and the calculation of defect size and the recognition of defect type were realized by judging the connectivity of the coordinates and the binary data.The results show that the accuracy of defects using this method is 0.1 mm.