Algorithm And Experimental Study Of Digital Holographic Imaging On Marine Plankton

Plankton is an important component of marine power and marine ecosystems.Coastal plankton has a great influence on coastal aquaculture industry and shallow sea ecological pollution prevention.The observation of plankton and its survival and reproduction is an important way to protect the aquaculture and protect the ecological environment.Digital holography has a wide range of applications in the field of spatial multi-level rapid imaging,such as particle field measurement,biological tissue microsurgery,and so on.Digital holography imaging techniques have also been introduced into near-ocean plankton for realtime observations.The existing underwater digital holography is influenced by many factors underwater,and there are many problems in image quality and measurement accuracy,and there is further potential for improvement.Based on the digital holographic in situ detection project of offshore plankton,the coexistence method of coaxial digital holography is used to observe the marine plankton form by charge-coupled device(CCD).In the experiment,we find that the problem of uneven brightness,edge blur and so on,we use the pentagon coin as the experimental object in the algorithm to introduce the adjust function,histeq function better solve this problem.In the experiment,the zero-pole image and the conjugate image produced by the coaxial recording are difficult to separate,which leads to the low image quality of the reconstructed object.We have discussed the off-axis holographic imaging condition in detail.The influence of the recording distance on the reconstructed image,The size of the reference light inclination angle and the calculation method of the tilt reference light angle when the conjugate image,the zero order image is separated.In the off-axis holographic experiment verification process,we introduced a new monitoring optical path in the reference optical path design.The innovative optical path enables a CCD to simultaneously record coaxial holographic information,off-axis holographic information,and reference light tilt angle information.The innovation of this monitoring optical path makes it possible to reproduce digital holography of single interferogram.At the end of this paper,the feasibility of phase-shift digital holography of single interferogram is discussed in detail.This study provides a theoretical basis for in situ recording and reproduction of offshore plankton and contributes to the design of underwater digital holographic systems.