Design Of ARM-based Portable Autofocus Digital Holographic Microscopy System

In recent years,with the continuous emergence of microbial intrusion,it has caused huge losses to some countries and regions,which has made people pay more attention to the detection of microorganisms in water.The traditional methods of microbiological detection in water require large and expensive equipment that cannot meet the needs of people.Therefore,this paper proposes a portable autofocus digital holographic microscopic reconstruction system based on ARM platform.Compared with the digital holographic reconstruction system of the traditional PC platform,the system has the characteristics of portability.Meanwhile,aiming at the shortcomings of the traditional digital holographic reconstruction algorithm that requires manual input for the reconstruction distance,this system realizes autofocus function of the digital holographic microscopic reconstruction system,so that the digital holographic microscopic reconstruction is portable and can meet people's needs.First of all,the thesis analyzes the basic knowledge of holographic theory including holographic principle,holographic imaging methods and holographic reproduction methods,and then introduces common image quality evaluation function and embedded correlation related principle technology.Then the hardware platform and reconstruction algorithm of the system are designed.After that,the hardware platform of the system is built,and the digital holographic reconstruction algorithm based on the embedded platform is achieved.At the same time,the autofocus of digital holographic reconstruction is achieved for the deficiency of the traditional algorithm.Finally,the overall function of the system is tested,and the test results are analyzed.The main work and research results of the thesis are as follows:(1)Design of digital holographic micro-reconstruction autofocus hardware system: firstly,the basic process of the whole system operation is explained,and then the overall hardware platform of the system is designed,including: optical path part,calculation processing part and display interaction part.Next the reconstruction algorithm is designed.Finally,the digital holographic reconstruction autofocus method based on the second-generation wavelet algorithm is designed for the deficiency of the traditional reconstruction algorithm.(2)Implementation of digital holographic microscopic reconstruction autofocus system: first,the framework of the system is explained,and the system hardware platform is built.Then the software platform system is built,including: U-Boot porting,Linux system porting,root file system porting and porting of related algorithm libraries.Next the implementation of the digital holographic microscopic reconstruction system software is introduced,including: FFT fast Fourier transform program,transfer function,digital holographic microscopic reconstruction program,image quality evaluation program,autofocus program and so on.Finally,the user graphical interface based on the embedded platform is designed and implemented.(3)System function tests and result analysis: this part mainly tests the reconstruction speed,accuracy and the autofocus accuracy of digital holographic microscopy reconstruction system.Finally,the experimental results are analyzed.