Verfahren und Vorrichtung zur Inspektion von ophthalmischen Linsen

• Main Authors: SITES, PETER, EBEL, JAMES A
• Format: Patent
• Language: German
• Published: 24.08.2006
• Subjects: CONTACT LENSES; MEASURING; OPTICS; PHYSICS; SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURESAS SPECTACLES; TESTING; TESTING STATIC OR DYNAMIC BALANCE OF MACHINES ORSTRUCTURES; TESTING STRUCTURES OR APPARATUS NOT OTHERWISE PROVIDED FOR

Disclosed is an ophthalmic lens inspection method and apparatus comprising a camera to capture an image of an ophthalmic lens which has been illuminated by a light source. Location and intensity at each camera pixel is converted to an electrical quantity which is then transferred and stored in a memory. A computer containing instructions for comparing the intensity and location values of the pixels starts near the center of the receptor field and continues toward the edge of the field until an intensity deviation is encountered. By evaluating the pixels containing intensity variation, an outline of the lens edge is attained. An annulus is generated enclosing the actual lens edge. All the pixels are changed from an absolute intensity value to a gradient value, represented by two transition edges. Feature extraction is performed to locate defective pixels and place them into groups. Once the groups have been determined each is given a score based on the number, type and severity of the defective pixels placed into that group. From that, a weighted score can be given to the entire lens and the lens either passes or fails.