CIRCULAR GRATING MOIRE DEFLECTOMETRY ANALYSIS BY ZEROTH AND FIRST RADIAL FRINGE ORDER ANGLE MEASUREMENT

The previous method of counting integer fringe orders in circular grat ing moire deflectometry yields inaccurate measurements, One way to imp rove the measurement accuracy with this method is by lowering the grat ing pitch. The attendant higher cost and possible encroachment of the diffraction limit, however, restricts the practicality of this approac h. An alternative analysis method, which measures the angle between th e zeroth and first radial fringe order, is presented in this paper to overcome this problem.