DEFECT DETECTING METHOD AND APPARATUS

In a defect detecting method and apparatus, the image of a bottle under inspection, which is conveyed while being spun, is divided into picture elements arranged in a matrix form, signals representative of the picture elements are generated sequentially and repeatedly, and the signals of the picture elements, on the same imaginary line perpendicular to the central axis of the image, are compared with each other, and the result of the comparison is used to detect a defect such as a foreign matter or a scratch.