Research On Biomedical Imaging Based On Incoherent Digital Holography

As an effective means of modern medical examination,3D optical imaging technology has an essential application in biological sample diagnosis.As a quantitative,label-free,and three-dimensional imaging technology,digital holography provides a simple and efficient method for analyzing biological samples.In particular,incoherent digital holography overcomes the dependence on high coherence light sources and realizes biomedical imaging under incoherent illumination.As an inherent attribute of the substance itself,the spectrum can detect and identify samples effectively.Using a LCTF to modulate the incident light of the incoherent digital holography system can realize the spectral analysis of biological samples.In addition,as a place where biological cells are prone to significant changes,the edge can accurately describe biological cells’ contour,structure,and other characteristics.Spiral phase modulation technology is introduced into incoherent digital holography to realize edge-enhanced imaging of biological samples.This paper mainly studies the application of incoherent digital holography in biomedicine,including using FINCH to realize the high-precision spectral image of biological tissue and obtain the spectral curve of any point on the sample surface.At the same time,the spiral phase modulation technology is introduced into the conventional Michelson incoherent digital holography system based on the Michelson interferometer to achieve high resolution and high contrast edge enhancement imaging of biological samples.The specific contents mainly include the following four parts:1.Study the imaging principle and characteristics of FINCH technology and incoherent digital holography technology based on the Michelson interferometer.The imaging resolution of the two incoherent digital holography systems is calibrated by the USAF1951 resolution target.Combined with microscopic imaging technology,biological tissue was taken as the test sample to verify further the imaging application of the two incoherent digital holography technologies in the biomedical field.2.Combining FINCH microscopic imaging technology with spectral technology,introducing LCTF into FINCH optical path,deducing the system’s point spread function,and further analyzing the correlation between transverse magnification and wavelength.Using three-dimensional amplitude objects and biological cells as the samples,this technology can extract the spectral curve of any point on the surface of the samples while three-dimensional holographic recording and realize the highprecision acquisition of spectral information.Based on the analysis and calculation of chromaticity theory,the fused image of biological tissue spectrum with threedimensional information is further obtained,which provides a new way for biological spectrum detection.3.The fundamental principle of the spiral phase FINCH system is analyzed.The edge enhancement imaging experiment is carried out with the USAF1951 resolution target and biological tissue as detection samples,and the effective edge detection of biological samples is realized.The incoherent digital holographic technology based on the Michelson interferometer is improved,and the SLM is introduced to realize the vortex modulation of the incident light.The imaging principle of the spiral phase Michelson incoherent digital holographic system is analyzed,and the point spread function is theoretically deduced,numerically simulated,and verified by experiments.Using the USAF1951 resolution target as the measured sample,the effects of threestep phase shift technology and generalized phase shift technology on the imaging resolution of the Michelson incoherent digital holography system are analyzed.Compared with edge imaging results from the spiral phase FINCH system,this system significantly increased the visibility of edge enhancement results.The high-resolution edge enhancement imaging of biological tissue and the scratch glass plate is realized by combining microscopic technology,providing a new way for biomedical sample imaging and industrial detection.