Method and apparatus for inspecting lightness on the surface of an object

U.S. Patent Number: 5296942

Abstract: An appratus for inspecting lightness on the surface of an object having at least first and second surface portions different in lightness, wherein an image of the first and second surface portions of the object are taken under appropriate illumination, the taken image is memorized, first and second reference lightness of the first and second surface portions are defined respectively, whether or not each pixel of the taken image belongs to either one of pixel regions defining the first and second surface portions are determined in accordance with values defining preliminarily memorized pixel regions respectively, lightness difference between each pixel of the taken image corresponding to the first surface portion and the first reference lightness is calculated, lightness difference between each pixel of the taken image corresponding to the second surface portion and said second reference lightness are calculated, and quality in lightness on the surface of the object are determined on a basis of the respective lightness difference.

Inventors: Yokoyama; Yoshio (Anjo, JP), Hieda; Takashi (Nagoya, JP), Asai; Toshihiro (Obu, JP)

Assignee: Nippondenso Co., Ltd. (Kariya, JP)

Application Number: 07/817,805

Issued: 1994-03-22

Expired: 2006-03-22

Classes: 358/461 ; 358/463; 358/464

Field of search: 358/463,464,465,466,457,461

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