A technique using diffractive elements for finding the absolute shape of a large-scale object is proposed. An accurate projected fringe profilometry can be built by applying the holographic technique in this system. The advantages of using the presented technique for projected fringe profilemetry are : (1) a large depth of field ; (2) very low fringe distortion ; (3) a compact design for the measurement system ; (4) high accuracy ; (5) fast measurement speed.

Abstract A projected fringe profilomertry ¡]PFP¡^ using a supercontinuum light illumination for micro-scale measurement is proposed. The supercontinuum light is generated by launching ultra short laser into a highly nonlinear photonic crystal fibers. The supercontinuum light with the following advantage¡G ¡]1¡^ Depth of the field is very large in the projected system. ¡]2¡^No speckle noise in the illumination system. Experiment results has shown that using supercontinuum light is superior to other illumination system This study indicates that the proposed measurement scheme could be applied to 3D shape measurements with large depth variation, especially for semi-conductor devices¡Bmicro electro-mechanical devices and biomedical species.