Three-Dimensional Shape Reconstruction Of Multi-Medium Phase Objects Based On Double-Channel Optical Phase Imaging

Cells are the basic units of biomass,and their morphological structures often associate with the functional state of the biomass.Therefore,the morphology of a cell is an important research content of life science and is also of great significance to clinical medical diagnosis.As a powerful non-destructive and label-free imaging tool,quantitative phase imaging technology provides various biological and physical properties for quantitative evaluation of cells.Although the phase diagram of the sample provided by this technology carries its internal structure information,the thickness and refractive index of the sample are coupled in the phase data.It is necessary to reconstruct the three-dimensional shape of the sample by decoupling the phase data.At present,many achievements have been made in the research of morphological reconstruction methods.However,most operations are complex,require a large amount of data and take a long time.It is not conducive to real-time monitoring of living cells.It can not meet the needs of the current clinical testing technology to the direction of miniaturization of equipment,simple operation and rapid detection.Based on this,a method to quickly reconstruct the three-dimensional shape of samples with less phase information is explored in this paper.This paper analyzes the advantages and disadvantages of dual-wavelength measurement method in phase decoupling application through experiments.From the perspective of imaging theory,this paper points out the limitations,causes and improvement ways of this technology which is only suitable for single medium samples.A method for reconstructing the three-dimensional shape of multi-medium phase objects based on two orthogonal dual-wavelength phase information is proposed.Taking nucleated biological cells as an example,according to this method,the two wavelength phase maps in the same direction of the sample are divided into regions according to the substructure distribution.The phase values of the reference points in different regions are analyzed correspondingly.And the cytoplasmic refractive index and its thickness distribution along the direction of incident light are extracted,so as to separate the phases caused by the cytoplasm and nucleus respectively.Further,the physical thickness of the reference point in the nucleus in the corresponding direction is obtained by combining the phase diagrams from the orthogonal direction.The average refractive index and the overall thickness distribution of the nucleus at the reference point are calculated successively,so as to reconstruct the three-dimensional shape of the sample from the three phase diagrams from the two orthogonal directions.According to the requirements of double-channel optical information acquisition for morphological reconstruction,a double-channel interference phase imaging device is designed in this paper.On this basis,a method for fast reconstruction of three-dimensional morphology of phase objects from two phase images from non-orthogonal direction is proposed.The designed imaging system adopts the idea of polarization splitting,and the double-channel optical information acquisition is realized by a single image sensor.The symmetrical common optical path design is adopted for the sample arm to reduce the system error and save the cost,which is also conducive to the miniaturization of the device.The corresponding reconstruction algorithm solves the relationship between the plane pixel coordinates projected by the control points along two non-orthogonal directions and their three-dimensional space coordinates by arranging the control points and using mathematical transformation.The three-dimensional coordinates corresponding to each pixel of the non-orthogonal projection plane are calculated and inversed,so as to realize morphological reconstruction.The three-dimensional morphological reconstruction algorithm proposed in this paper is suitable for multi-medium phase objects.It only needs to collect sample phase information from two directions.It has the characteristics of convenient operation,small amount of calculation,good universality and fast speed.It can provide a certain reference for the research of three-dimensional morphological reconstruction algorithm of phase objects and clinical medical examination.