Cognex Corporation

Feng Qian

John F Filhaber

Michael C Moed

Fariborz Rostami

This invention provides a system and method for detecting and imaging specular surface defects on a specular surface that employs a knife-edge technique in which the camera aperture or an external device is set to form a physical knife-edge structure within the optical path that effectively blocks reflected rays from an illuminated specular surface of a predetermined degree of slope values and allows rays deflected at differing slopes to reach the vision system camera sensor. The light reflected from the flat part of the surface is mostly blocked by the knife-edge. Light reflecting from the sloped parts of the defects is mostly reflected into the entrance aperture. The illumination beam is angled with respect to the optical axis of the camera to provide the appropriate degree of incident angle with respect to the surface under inspection. The surface can be stationary or in relative motion with respect to the camera.

System and method for detecting defects on a specular surface with a vision system

An illumination assembly is provided for use with a light source and an illumination target. A first light collector can be disposed to receive and direct light from the light source. A first diffuser can be disposed at least partly between the first light collector and the illumination target. The first diffuser can be configured to diffuse at least part of the light directed by the first light collector to provide a first illumination pattern on the illumination target.

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Natick, MA, United States of America

Feng Qian