Dynamic Scattering Medium Imaging Method Based On Optical Memory Effect

In daily life,visible light is a common carrier for people to obtain image information of objects and an important way to perceive the environment.When there is no obstacle between the observer and the observed object,direct observation can be realized;when there is an obstacle,direct observation cannot be realized,such as the observation of objects on the other side of smoke or clouds,the imaging of organs under biological tissues,etc.The reason is that when photons interact with these media,the original transmission direction becomes random,so the information of incident light field is lost when they are emitted.In order to solve the inconvenience caused by this phenomenon,many methods of imaging through scattering media came into beingIn this paper,the main work is focused on the method of single frame optical speckle correlation imaging,which uses the strong scattering characteristics,statistical characteristics and optical memory effect of random scattering medium.Through the autocorrelation calculation of the speckle field image received by the detector and the phase recovery algorithm,the adverse effects of scattering medium in the imaging process are eliminated,so as to image the target fast with high resolution.Compared with other imaging methods such as adaptive optics technology,ghost imaging technology,wavefront correction technology,time inversion technology and other imaging methods penetrating scattering medium,this method has the advantages of high time resolution,non-invasive,high robustness and low cost,so it has higher practical value and wider development prospect.Based on the full demonstration of the theoretical model of speckle correlation imaging,we have carried out experimental verification of this method,and discussed and verified different methods in the process of filtering processing and phase recovery,in order to develop the best scheme of efficient and perfect reconstruction.On this basis,we expand the application scenario of this method,and discuss and experiment the dynamic target and dynamic scattering medium respectively.First of all,for the moving object,the theoretical model of the static object is modified,and the imaging process is realized through the speckle difference autocorrelation method.At the same time,the real-time positioning of the moving object and the measurement of the moving speed can also be realized.Then,the imaging of the static object is realized in several different moving media,and the appropriate media is selected for quantitative analysis.Although the moving speed of the media is limited by the size of the imaging object and the exposure time of the detector,there is a large local limit,but it also provides a theoretical basis and experimental basis for the imaging through the dynamic medium to a certain extent Based on this,the application range of speckle correlation imaging is widened,which has a high practical value.