Research On Microscopic Image Enhancement Method And Application Of Lensless Digital Holography

Digital holography is a new method which can record the three-dimensional information of waves field.It uses digital camera instead of holographic film to store and capture object waves in a digital way.In order to reconstruct the object waves,it uses the light source simulated by computer to illuminate the hologram,so as to obtain the original complex amplitude information of the object.Compared with traditional film holography,digital holography can conveniently,quickly and easily reconstruct the object phase information,has a powerful image processing technology which can be used to manipulate the light field.Therefore,it is widely used in information encryption,microscopic observation,medical diagnosis,component detection and other fields.The main research contents include imaging optical path,image processing algorithm and practical application.The knowledge background and recent advances of digital holography are studied.The theory and method of digital holography are analyzed.The method of how to suppress speckle noise and conjugate image in digital holography is studied.Its application in the field of information encryption is realized.The main researching contents and innovative achievements are given as follows:1)The speckle noise in digital holography is studied,and the feature and model of speckle noise are summarized.The digital holographic optical path without lens is realized by computer simulation.The acquired holographic image is prone to the speckle noise which affects the image resolution.By analyzing the existing image enhancement methods,a fusion algorithm is proposed and compared with the experimental results of other algorithms.2)This paper proposes to use the Gaussian process regression to solve the TIE equation algorithm to suppress the conjugate image in the holographic image,and carries on the computer simulation experiment.The experimental results show that the proposed method is better than the traditional GS method.3)A new image encryption method based on multi planar Fresnel digital holography and Arnold transform is studied,and the detailed theory and process of encryption are given.Thesimulation results show that the encryption algorithm is operable,stable and safe.