Research Of Coded Aperture Correlation Holography Imaging Through Scattering Medium

When light passing through the scattering medium,such as ground glass,clouds,smoke,and biological tissues,it will be strongly scattered due to inhomogeneous refractive index inside the medium.However,traditional direct imaging techniques mostly rely on ballistic photons that have not been scattered.Traditional imaging methods cannot achieve imaging through scattering medium.Speckle correlation,shower-curtain effect,optical transmission matrix,and wavefront shaping techniques are the common methods used to image through scattering medium.However,the disadvantages such as low resolution,limited field-of-view,and narrow bandwidth were emerged in the imaging process.Coded aperture correlation holography(COACH)is a new incoherent holography technology proposed in 2016.It widely used in the fields of astronomical and biomedical science imaging because of excellent imaging performances,for instance,high resolution,large depth of field and real-time imaging.My objective in this paper is to demonstrate the role of the COACH in the field of scattering imaging,and to research the mechanism of imaging through scattering media using incoherent COACH method.In addition,dynamic target tracking and three-dimensional imaging through scattering media were realized,and expansion for depth of field were achieved.The specific work is as follows:(1)A COACH imaging through scattering medium model was established,which based on existing imaging theories of COACH technology and combining with the characteristics of scattering medium.The constraints of traditional optical principles were broken to achieve the acquisition and interpretation of optical image information for complex target,and the drawback of traditional holographic technology that cannot apply to incoherent imaging through a scattering medium were overcomed,furthermore,the object hidden behind scattering medium was reconstructed with high-resolution.(2)Binary targets,two-dimensional moving targets,and three-dimensional targets rapid reconstruction through a scattering medium were achieved.The COACH combined with a robust non-linear reconstruction algorithm can recover these targets rapidly and efficiently.It is noted that the resolution of the reconstructed target can be comparable to that of tranditional lens imaging,and the reconstruction time is only 1/20 of the traditional deconvolution algorithm.(3)The depth-of-field of the COACH imaging system through a scattering medium was extended.The scattering imaging system based on the COACH technology has a depth-of-field of 21.7mm,which is three times that of traditional scattering imaging technology.Moreover,the depth of field of COACH system based on PSF estimation technology can be extended to 26.3mm,and large depth of field imaging through scattering medium were realized.In summary,a research on imaging through scattering medium based on COACH technology was represented in depth,as well as high-resolution and large depth of field imaging were realized.The proposed imaging method has the advantages of fast speed,high precision and simple setup,which can promote the development of new scattering imaging technology.