GRATING NOISE REMOVAL IN MOIRE TOPOGRAPHY

The averaging process used to remove the grating lines during photographical recording of moire topograms by moving the grating is well known. It is explained why this technique fails to work in modern video based moire setups. A new method for grating line removal from topograms recorded by video camera is proposed. The method is based on the averaging of video frames recorded during the translation of the grating at a specified speed. The mathematical description of the process is formulated and the condition for the translation speed is derived. An experimental demonstration of the new method is given using a shadow moire interferometer.