Coaxial Digital Holography System To Measure Underwater Microbes

Water is the source of life.With the improvement of people's living standard and the development of industrialization,the problem of water pollution is becoming more and more serious.The species,quantity and proportion of microorganism in water are important indexes to measure water pollution.The monitoring of water quality and the control of water pollution can be realized by measuring the main parameters of underwater microorganisms.Two-view coaxial digital holography is improved on the structure of classical single-view coaxial digital holography.Its structure is simple and stable,and it can obtain two surface holograms of measured objects simultaneously on the target surface of a camera.It has more advantages in surface area volume measurement,non-destructive testing,holographic microscopy and other aspects.In this paper,coaxial digital holography is used to conduct experimental research on the relevant parameters of microorganisms in water.The main contents are as follows:This paper describes the basic principle of coaxial digital holography recording and reproducing,analyzes the characteristics of three common reproducing algorithms,and determines the use of angular spectrum algorithm to reproduce microbe holograms.The recording characteristics of Two-view holography were analyzed to determine its feasibility in the direction of microbial surface area and volume.A complete hardware system is built and a virtual impactor model is designed for the size classification of microorganisms and the measured microorganisms within a certain volume range are obtained.The single-view coaxial holographic system and the Two-view coaxial holographic system are constructed.The cabin for carrying the experimental system is designed and made.The hologram obtained by the single view holographic system is numerically calculated and processed to realize the automatic identification of microorganisms in water and obtain the information of their shape,quantity and spatial distribution.The surface area and volume information of the measured microorganism were restored by hologram processing obtained from the Two-view holographic system.The accuracy of area and volume of standard 45?m particle measurement system was verified.