Patent ID: 7884949

Claim:
A three-dimensional measuring apparatus comprising: a work stage fixing a measuring object; a projection unit comprising a light source, a grating through which light irradiated from the light source is penetrated, and a projection lens imaging a grating image produced by the grating on the measuring object, the projection unit allowing grating image light to be incident onto the measuring object, alternately by N times in a first direction and by N′ times in a second direction, wherein N and N′ are natural numbers greater than or equal to two; an image receiving unit comprising an imaging lens and a camera, the image receiving unit receiving first reflection image light with respect to the first direction and second reflection image light with respect to the second direction reflected by the measuring object; a control unit compensating for a shadow region of the measuring object by using the first reflection image light and the second reflection image light received in the image receiving unit to produce a three-dimensional image of the measuring object, the control unit setting a focus distance of the image receiving unit by using a reference surface that is supported by the work stage; and a reference surface light source irradiating light onto the reference surface, wherein the control unit maintains the focus distance between the measuring object and the image receiving unit to be constant, by receiving the light irradiated from the reference surface light source onto the reference surface and measuring a distance between the measuring object and the image receiving unit.