Patent RU-2762130-C2 (RU)
Title: System and related method for measuring optical characteristics of glass sheet on process line
Inventor: VILD MICHAEL J
IPC: B65G49/06
Filed: 2018-02-08
Granted: 2021-12-15
Abstract: FIELD: measuring equipment. 
     SUBSTANCE: invention relates to a method and a device for measuring both the optical distortion of a transmitted image and small defects in glass sheets, embedded in a process line in a system of glass sheet processing. A system installed on a process line for measuring optical characteristics of a glass sheet, installed in a system for the manufacture of glass sheets, is claimed, containing one or more processing stations and one or more conveyors for transporting a glass sheet from station to station during processing, while the system installed on the process line contains: a device for measuring small optical or view-obstructing defects in the first selected area of a glass sheet, containing the first lumen screen containing contrast elements arranged in the form of a given pattern. It also contains the first chamber for obtaining the first image data set containing at least one image of the first lumen screen associated with the first selected area of the glass sheet, when moving the glass sheet to a pre-selected position on the conveyor between the chamber and the first lumen screen, and a computing device containing at least one processor programmed to implement logic for receiving the first image data set, generating an intensity map from the first image data set and identifying and locating small defects from the intensity map. In this case, the logic for generating an intensity map from the first image data set includes logic for generating a Fourier transform of image data, demodulating a Fourier transform, generating an inverse Fourier transform of demodulated data, extracting a two-dimensional complex number associated with each pixel, while the specified complex number has a phase component and a magnitude component, and generating an intensity map of the inverse Fourier transform by determining the square root of the sum of squares of the imaginary part of the two-dimensional complex number and the real part of the two-dimensional complex number for each point of interest in the image. It also contains a device for measuring the transmitted optical distortion in the second selected area of the glass sheet, containing the second lumen screen containing contrast elements arranged in the form of a given pattern, the second chamber for obtaining the second image data set containing an image of the second lumen screen with a glass sheet placed in a pre-selected orientation between the second chamber and the second lumen screen, and a computing device containing at least one processor programmed to implement logic for receiving the second image data set associated with a glass sheet and determining the selected feature of optical distortion associated with points of interest in the second image by generating a phase map from the second image data set and generating the selected feature of optical distortion from the phase map.  
     EFFECT: increase in the accuracy of measuring optical characteristics of a glass sheet. 
     18 cl, 11 dwg