Method for detection of surface defects

Claim 1

A method of continuously and automatically monitoring broad surfaces of a rapidly moving metal material for the detection and analysis of surface variations which exceed established acceptable surface conditions for the purpose of determining the occurrence of surface defects that are considered rejectionable and for providing accurate defect classification of the same, comprising: homogeneously exposing the moving surface to visible and/or invisible specular and diffused electromagnetic radiation in a selected range of wavelengths to enhance surface features and thereby aid detection of surface defects, rendering the rapidly moving surface momentarily motionless, detecting the presence of one or more rejectionable defects with a plurality of sensors located to view the entire width of the material, transmitting an electronic image of the area containing a defect from one or more of the sensors to a device for storing the image for subsequent display and analysis, the image containing grey scale levels that represent varying intensities of electromagnetic energy reflected by the defect, providing a range of grey scale levels that represent the range of intensities of electromagnetic energy reflected from a surface that is free of rejectionable defects, comparing the grey scale levels of the image with the defect with the range of grey scale levels that represent a surface free of rejectionable defects, and viewing and analyzing only those images of the surfaces on a freeze frame monitor that have grey scale levels outside the grey scale range of inten­sities that indicate a surface free from rejectionable defects.

Claim 2

A method of continuously and automatically monitoring broad surfaces of a rapidly moving metal material for the detection and analysis of surface variations which exceed established acceptable surface conditions for the purpose of determining the occurrence of surface defects that are considered rejectionable and for providing accurate defect classification of the same, comprising: homogeneously exposing the moving surface to visible and/or invisible specular and diffused electromagnetic radiation in a selected range of wavelengths to enhance surface features and thereby aid detection of surface defects, rendering the rapidly moving surface momentarily motionless, detecting the presence of one or more rejectionable defects with a plurality of sensors located to view the entire width of the material, transmitting an electronic image of the area containing a defect from one or more of the sensors to a device for storing the image for subsequent display and analysis, the image containing grey scale levels that represent varying intensities of electromagnetic energy reflected by the defect, providing a range of grey scale levels that represent the range of intensities of electromagnetic energy reflected from a surface that is free of rejectionable defects, comparing the grey scale levels of the image with the defect with the range of grey scale levels that represent a surface free of rejectionable defects, and viewing and analyzing only those images of the surfaces on a freeze frame monitor that have grey scale levels outside the grey scale range of inten­sities that indicate a surface free from rejectionable defects.