| 摘要 |
PROBLEM TO BE SOLVED: To provide the focus adjusting method of the moire fringe observation device which can easily and speedily project a projection grating on a subject in a complicated shape and can be put in focus as to a moire fringe observation system. SOLUTION: The moire fringe observation device equipped with an image pickup optical system which projects the grating image on the subject 4 by a grating fringe projection optical system and picks up an image of the projected grating fringes through the grating 6 to obtain a moire topograph image enables a photographer to adjust the focus of the projection lens 3 while observing the projected grating image nearby the subject 4, and further to adjust the focus of a photographic lens 5 according to the photographed moire image. The focus adjustment is made by adjusting the distance between the lens and grating, i.e., by moving the lens to or away from the grating or moving the grating to or away from the lens. |
