GLASS INSPECTION

A method of detecting a defect in a sheet of glass is described comprising the steps: (i) directing a converging beam from a source of illumination onto a surface of the sheet of glass to illuminate the defect; (ii) focusing an image capture device onto a first plane to image the defect in the sheet of glass; (iii) capturing a first image of the defect; (iv) carrying out an adjustment step; (v) capturing a second image of the defect. Each of the first and second images comprises a respective first portion from the illuminated defect and a respective second portion due to reflection of a portion of the beam from the glass surface. In the first image of the defect the first portion is brighter than the second portion, and in the second image of the defect the first portion is darker than the second portion. Apparatus for carrying out the method is also described.