Patent ID: 6570607
Filing Date: 2003-05-27
Classification: G01N,G06T

Abstract:
A light-and-shade inspecting apparatus for picking up an image of an object to be inspected, and based on an image data thereof inspecting a light and shade on the object, comprising:an image pick-up device adapted for picking up an image of the object to output an image data; an integrated image calculating portion adapted for dividing the image data outputted from said image pick-up device into a mesh pattern of meshes which are equivalent in area to each other and then adding together the image data within each of the divided meshes to obtain an integrated image which is represented by F(u,v)=&Sgr;&Sgr;f(mu+uâ€²,nv+vâ€²), wherein u and v represent a u-v coordinate system of said meshes by which said image data is divided into said meshes of mÃ—n pixels; a differentiated image calculating portion adapted for performing a difference operation between each pair of meshes separated by a predetermined interval from each other with respect to their corresponding two integrated images obtained by said integrated image calculating portion, wherein said difference operation is represented by D(u,v)=|F(u+&Dgr;u, v+&Dgr;v)âˆ’F(uâˆ’&Dgr;u, vâˆ’&Dgr;v)| and wherein each of &Dgr;u and &Dgr;v represents said predetermined interval between two meshes used for obtaining the difference value; a defect detecting portion adapted for comparing a value obtained by said differentiated image calculating portion with a predetermined value to detect a defect portion which is partially different in luminance from other portions on the object; an average value calculating portion adapted for calculating an average value of the integrated image obtained by said integrated image calculating portion; and a light-and-shade deciding portion adapted for deciding whether the defect detected by said defect detecting portion comprises a light defect or a shade defect based on the average value obtained by said average value calculating portion ad values of the integrated images in respective pairs of meshes separated by the predetermined interval from each other which have been subjected to the difference operation.