Patent ID: 7394536
Filing Date: 2008-07-01
Classification: G01B,G01N

Abstract:
1. A method for inspecting a front surface shape, comprising: projecting a stripe pattern of light and dark segments on a transparent plate-shaped object; capturing a reflection image of the stripe pattern produced by a front surface and a rear surface of the transparent plate-shaped object with a camera; determining whether a signal wave corresponding to the reflection image captured by the camera is in a state that a first signal wave portion corresponding to a first dark portion of the stripe pattern reflected from the front surface and a second signal wave portion corresponding to a second dark portion of the stripe pattern reflected from the rear surface are separated from each other and do not coincide; analyzing the signal wave corresponding to the reflection image captured by the camera to recognize a signal wave that corresponds to an image reflected from the front surface, wherein the first signal wave portion is determined by comparing magnitudes of the first and second signal wave portions to determine lowest intensity portions as the first signal wave portions, the lowest intensity portions corresponding to the image reflected only by the front surface; and using the first signal wave portions which correspond to the image reflected only by the front surface to inspect the front surface shape.