Patent ID: 8284247
Filing Date: 2012-10-09
Classification: G01N,G06T

Abstract:
1. A method for detecting and evaluating defects that completely penetrate through a foil or film, said method comprising the steps of: passing a flat foil or film between at least one optical image capture device and at least one elongated light source comprising an infinite number of point sources that are not in phase and are emitting light independently from one another, wherein said optical image capture device is positioned on one side a first surface of said foil and at a first distance from said first surface and said elongated light source is positioned on a second opposite side of said of said foil or film; periodically capturing automatic computer-controlled image of the foil surface with said image capture device to produce at least a first image; transmitting said at least first image to a control computer; processing the transmitted first image to detect whether a first light spot image associated with a defect is present and, if present, determining the brightness and area of the first light spot of said first light spot image; calculating a first generalized index of said first image by multiplying said brightness and said area of said first light spot image; stopping the movement of a foil or film upon detection of said first light spot image; moving the image capture device to a second distance from the foil or film surface; repositioning said image capture device in the plane parallel to foil or film surface; stopping said image capture device when the light spot of said defect comes into the focus; automatically capturing a second image; transmitting said second image to said computer; processing said second image to form a second light spot image determining the brightness and area of the second light spot of said second light spot image; calculating a second generalized index of said second image by multiplying said brightness and said area of said second light spot image; calculating a third generalized index using said first and second generalized indices; and evaluating the dimensions of said through-penetrating defect in said foil or film by comparing the third generalized index with calibrated generalized indices.