Research On Digital Holographic Speckle Denoising And Reproduction Technology

Digital holography is a kind of technology developed on the basis of traditional optical holography,combined with optical imaging technology and computer technology.The technology used for recording and reproducing optical holography theory,using a charge coupled device(CCD)or complementary metal oxide semiconductor(CMOS)is used to substitute for recording hologram holographic plate in traditional optical holography,the hologram digital device recorded by digital reconstruction using computer programming.The whole process digitalization of hologram recording,storage and reproduction is realized,which not only greatly reduces the reproduction time of holograms,but also makes it possible for remote synchronous reproduction of holograms.In recent years,digital holography has attracted the attention of researchers at home and abroad.The research is very extensive,mainly focused on holographic imaging theory,reconstruction algorithm,and how to improve the accuracy of reconstructed image and improve the signal-to-noise ratio.This paper summarizes the development results of digital holography at home and abroad so far,and on this basis determines the main research content of this paper.There are six chapters in this paper,which can be divided into three parts.The main contents are as follows:The first & the second chapter is the first part of the paper.In the first chapter,the research background,development process and research status of digital full technology are summarized,and the content and meaning of this paper are also discussed.In the second chapter,the theoretical knowledge of the optical basic theory used in digital holography is given.The mathematical expression of the interference diffraction of light is given in detail,and the recording and reproducing of the hologram are mathematically deduced.The recording and reproducing conditions of digital holography are explained in detail.The second part of the paper contains third,fourth,fifth chapters.This part is the main content of the article.In the third chapter,digital holographic numerical reconstruction algorithm is studied.including two methods of Finel transform and convolution.The fourth chapter mainly focuses on the improvement of digital hologram reconstruction image quality.It mainly includes two parts: software optimization and hardware improvement.In the fifth chapter,a space light modulator,a very important optical device in holographic technology,is introduced.The application of the device in the digital holographic experiment is analyzed in detail.The sixth chapter is the third part of this paper,summarizing the shortcomings of this paper and planning for the follow-up research.The main points of this paper are as follows: three dimensional reconstruction of object image,in the face of the unavoidable digital holographic speckle noise,on the basis of traditional digital image processing,make adjustments on the hardware and light path.The small aperture diaphragm is added to the front of CMOS to adjust the size of the aperture to filter the high frequency noise of the space.In the 3D reconstruction of digital holography,the hardware of the liquid crystal spatial light modulator is quickly reproduced.