Study On The Mechanism And Applications Of Digital Holographic Interferometry

Digital holography(DH) is a new holographic technique, It uses a camera of Charged-coupledDevice(CCD) to replace the traditional holographic material, and realized a totally digitalizedholographic process of recording, storing and reconstruction. With the rapidly development ofcompute science and high resolution image sensor, the digital holography technology is gaining moreand more attention. Digital holographic interferometry is an important holographic measurementtechnique. In this thesis, we use digital holographic interferometry measure the deformation andvibration.The main research work of this thesis are as follows:1. Based on the theory of computer holography, and with help of the technique of digital holography,holographic recording and reproduction process are simulated by computer under different conditions.The affect of some factors, such as system vibration and background light, are analyzed. It providestheory for experiments which study on digital holographic interferometry.2. Tiny deformation of a metal plate is measured by double-exposure digital holographicinterferometry. In order to obtain a better reconstruction effect, five methods of reconstructionalgorithm are used. Based on the traditional method of light intensity addition, the light intensitysubtraction method, light field addition method, light field subtraction method as well as light fielddivision method are firstly proposed. They provide new ways for obtaining better reproductionimages.3. The vibration amplitude of the piezoelectric ceramics is measured by digital imaging time-averageholography. Due to the low resolution of CCD, only small objects can be measured generally bytime-average digital holography. In this thesis, a imaging lens is introduced into the optical systemto enlarge the area of measured objects. To prove the effectiveness of this optical system, the vibrationof a large object is measured by this time-average digital holographic technique. This technologyprovides a new solution for the digital hologram application in measurement of vibration.