METHOD FOR INSPECTING SURFACE TEXTURE DIRECTION OF WORKPIECES

• US 20080008375A1
• Filed: 07/06/2006
• Published: 01/10/2008
• Est. Priority Date: 07/06/2006
• Status: Abandoned Application

• Current Assignee: Federal-Mogul Worldwide Incorporated (Apollo Global Management, Inc.)
• Original Assignee: Federal-Mogul Worldwide Incorporated (Apollo Global Management, Inc.)
• Inventors: Petersen, Russell H.
• Application Number:
  US11/428,974
• Publication Number:
  US 20080008375A1
• Time in Patent Office: Days
• US Class Current: 382/141
• CPC Class Codes: G01B 11/303 using photoelectric detection means
• CPC Class Codes: G01N 21/952 Inspecting the exterior surface of cylindrical bodies or wires G01N21/956 takes precedence
• CPC Class Codes: G01N 21/95607 using a comparative method
• CPC Class Codes: G06T 2207/30136 Metal
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/0006 using a design-rule based approach
• CPC Class Codes: G06T 7/44 using image operators, e.g. filters, edge density metrics or local histograms

Abstract

A method of detecting defects in a workpiece having a surface with directional surface texture, comprises taking a gray scale photo image of the surface and assigning a brightness value to the pixels of the image. The brightness values of neighboring groups of the pixels are compared to develop brightness slope values of the neighboring groups. The image is then transformed so that the individual brightness values of the pixels are replaced with the associated brightness slope values representing the rotational direction of the brightness slope in degrees. Missing gradient information and/or changes in gradient direction are detected as flaws in the surface.

Claims

1. A method of detecting defects in a workpiece having a surface with directional surface texture, comprising:

taking a gray scale photo image of the surface and assigning a brightness value to the pixels of the image;

comparing the brightness values of neighboring groups of the pixels to develop brightness slope values of the neighboring groups and transforming the image so that the individual brightness values of the pixels are replaced with the associated brightness slope values representing the rotational direction of the brightness slope in degrees; and

detecting any missing gradient information or changes in gradient direction as flaws in the surface.

2. The method of claim 1 wherein the workpiece is advanced along a continuously moving conveyor line relative to at least one stationary camera used for taking the gray scale image.

3. The method of claim 1, wherein the workpieces are fed along the conveyor line with the rotational directions of the textured surfaces randomly presented.