Patent ID: 8279450

Claim:
An intra-oral measurement device comprising: a light projecting unit for irradiating a measuring object including at least a tooth within an oral cavity with light; a lens system unit for collecting light reflected by the measuring object; a focal position varying mechanism for changing a focal position of the light collected by the lens system unit; an imaging unit for imaging light passed through the lens system unit; a pre-scan light projecting device for emitting guide light focused at a position distant from the light projecting unit by a distance set in advance; and an image processing unit, which without image the light passed through the lens system unit with the imaging unit when a circularity of the guide light emitted from the pre-scan light projecting device and projected onto the measuring object is lower than a threshold value set in advance, and images the light passed through the lens system unit with the imaging unit when the circularity of the guide light is higher than the threshold value set in advance.