US Patent 7420671 Defect inspection method and apparatus for transparent plate-like members

A defect inspection method and apparatus for a transparent plate material for detecting a bubble, a scratch, a foreign matter, and another defect existing on or in the transparent plate material including regarding a defect candidate as a defect, when the defect candidate is located in both first and second images, and regarding the defect candidate as a pseudo defect, when the defect candidate is located in only one of the first and second images.