Patent ID: 6614918
Filing Date: 2003-09-02
Classification: G01N

Abstract:
A light-and-shade inspection apparatus for picking up an image of an object to be inspected having a substantially constant width and traveling in a first direction to produce an image data and then performing a light-and-shade inspection of the object based on the image data, comprising:a line-sensor camera for picking up an image of an object across an overall width thereof to produce an image data; a projection operational portion for calculating a projection data by adding together the image data by a predetermined number of lines in said traveling direction, said image data being produced at each scan of said line-sensor camera at a predetermined position along the width of the object; a background lightness operational portion for calculating a background lightness of the object across its width, based on the projection data produced by said projection operational portion; and a difference operational portion for subtracting the background lightness produced by said background lightness operational portion from the image data produced by said line-sensor camera, thereby substantially eliminating variations of the background lightness across the width of the object from the image data.