THREE-DIMENSIONAL SHAPE MEASUREMENT METHOD AND THREE-DIMENSIONAL SHAPE MEASUREMENT DEVICE
A three-dimensional shape measurement method and a three-dimensional shape measurement device in which holography is used, wherein there is achieved a highly accurate three-dimensional measurement of the shape of a moving object. This measurement method comprises: a projection step for projecting an interference pattern (F) having a single spatial frequency (fi) on the surface of an object
a recording step for recording the projected interference pattern (F) as a digital hologram using a light-receiving element
and a measurement step for generating a plurality of reproduced images in which the focal distance has been changed from that of the recorded digital hologram, and deriving the distance to each point on the surface of the object through the application of a focusing method on the interference pattern (F) on each of the reproduced images. The measurement step comprises an interference pattern extraction step for extracting the component of the single spatial frequency (fi) that corresponds to the interference pattern from each of the reproduced images by spatial frequency filtering when the focusing method is applied. The interference pattern extraction step makes it possible to achieve a highly accurate measurement using the focusing method in which the effect of speckles can be reduced and the advantage of free-focus image reproduction using holography can be utilized.