Holographic phase shifting technique for 3D profilometry

Based on holographic technique,the principle and experimental device for 3D profile measurement are introduced in the papaer.The holographic interference fringe is used instead of projected fringe.Meanwhile,phase shifting technique is used to calculate the phase of the fringe and the wrapped phase distribution of the holographic fringe is produced.Then the unwrapping process will be made by means of the height obtained based on the least square of the projected fringe.Thus,phase measurement can be obtained with higher precision.Finally,the 3D shape data can be produced according to geometric relationship between phase and the object height.