The Research Of Digital Real-time Holography Metrical Method

Digital hologaphy is a new holographic imaging tehnique and a mix of optical holography, computer processing and electronic image recording. The advantages of digital holography include digital processing,quantitative analysis of phase field and real-time concurence. It is becoming a highlight in the field of optical information Proessing.A set of new digital real-time holographic measurement system is developed. In order to overcome the shortcoming of ordinary digital holography and meet the experimental requirement, a kind of equivalent 4f system is proposed, and the formulae used to calculate the transverse magnification and the formulae used to the CCD position in the light path of digital holography are derived in this dissertation. The disposal of the light path can then be adjusted according to the size of specimen. The digital real-time holography can be used to measure an bigger area. In order to advance the quality of digital hologram, the related data process method is also proposed and a method of eliminating the zero-order diffraction but remaining high frequency information of object light is derived theoretically.The reliability of the digital holography measurement system is testified by comparing the digital real-time holograms with classical real-time holograms. Besides, the laws about the derivation and evolution of interference fringes discovered in the digital real-time holographic experiment supply the new means for us to count the interference fringes, and to determine the dangerous position in the simulation specimen of the equipment component especially.