ELECTRONIC FRINGE ANALYSIS FOR DETERMINING SURFACE CONTOURS

摘要

A method for determining the contour of a diffuse surface, including the location of the workpiece (12) on a reference plane (14). A computer (16) is employed to generate a virtual grating of fringe patterns that vary pixel gray scale values sinusoidally in a horizontal image row. The gray scale variation is repeated for all image rows, and said values are supplied to a video projector (18) which projects the values onto the diffuse surface of the workpiece (12) at an angle relative thereto. The diffuse surface and gray scale values are viewed with a video camera (20), which camera acquires and provides electronic images of the diffuse surface and values without the use of a camera grating. The viewing is performed at an angle different from the angle at which the fringe pattern is projected onto the diffuse surface. The video camera then supplies signals to the computer that represent the electronic images acquired by the camera, and the computer is employed to process the signals in a manner that determines the contour of the diffuse surface.