Patent ID: 8279448

Claim:
A shape measurement apparatus comprising: a plurality of laser devices which generate beams, emit a beam of a specific frequency from among the generated beams, and output interference signals for detecting wavelengths of the generated beams, respectively, the laser devices including two semiconductor lasers for generating the beam; an optical unit for allowing the emitted beams to be projected on a surface of a target object to be measured, and generating an interference pattern of the target object; a plurality of shutters for allowing the emitted beams to be illuminated on the optical unit or preventing the emitted beams from being illuminated on the optical unit; an image pickup unit for capturing an image of the generated interference pattern; and a controller for detecting the wavelengths of the generated beams from the outputted interference signals, and controlling the laser devices on the basis of the detected wavelengths and the generated interference pattern, wherein the laser device includes an interference signal generator which generates the interference signal for detecting the wavelength of the generated beam, and outputs the generated interference signal, an external reflector which has the specific frequency serving as a resonance frequency, receives the generated beam, and feeds back the received beam to the semiconductor laser when a frequency of the received beam is equal to the resonance frequency, and an optical transmission unit for emitting the generated beam to an external part when the external reflector feeds back the received beam.