| Human's eyes and existing imaging devices can only detect the amplitude information of light-wave,but the phase information of light-wave is completely lost.But in fact,it is not the amplitude but the phase that carries most of the information in the image.Especially for small objects such as cells,their phases contain more information about the characteristics of cells,which can reflect the growth status of cells.Therefore,it is of great significance to study how to obtain cell phase information for the research of biological cytology and drug-development.As a common phase measurement method,digital holography has been a hot research topic in the field of microscopic imaging.Based on the background,we built a set of transmission live cell digital holographic microscopy imaging system and its supporting software.Based on the principle of digital holography,three main processes of phase recovery from holographic image are introduced: phase extraction,phase unwrapping and phase aberration compensation.In the phase aberration compensation part,several common compensation methods are studied and compared.On this basis,a phase tilt aberration correction compensation method based on sub-pixel spectrum translation is proposed.This method can not only compensate the aberration introduced by spectrum operation in phase extraction,but also compensate and correct the phase aberration caused by the optical path and sample of the system if the method is used to the whole pixel level.In addition,on the basis of Zernike polynomial fitting phase aberration,this paper proposes an iterative fitting method.This method can separate samples from background by binary processing and multiple Zernike fitting,which can improve the fitting aberration accuracy and obtain better phase compensation results.Finally,the phase recovery process of Hela cells under 20-fold and 10-fold mirrors was completed on the transmission digital holographic microscopy imaging system. |
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