| 摘要 |
PURPOSE:To easily, effectively detect an abnormal position by irradiating an inspecting unit with a one-dimensional latticelike pattern which is periodically varied in a light intensity in one direction, reading an image of the unit, and differentiating it according to a streaking direction of the lattice. CONSTITUTION:A projector 12 is controlled by a controller 16 to irradiate an inspecting unit of a surface 10 to be inspected of an element to be inspected with an enlarged image 13 of a one-dimensional latticelike pattern which is periodically varied in an optical permeability in one direction (x-direction). An image of the unit is read by a CCD camera 14, and its result is fetched to an arithmetic processor 18. When the processor 18 differentiates pattern image information in a streaking direction (y-direction) of the lattice, a read signal corresponding to a light intensity of the y-direction of the result becomes substantially '0' at its differentiated value in the y direction of light and shade corresponding to the pattern of the pattern image and varies to positive-negative of large value at parts corresponding to the image of a flaw of the unit. Accordingly, when this positive or negative value is binarized by using suitable threshold value, only the flaw part can be detected. |
