Edge enhancement is a fundamental and important topic in imaging and image processing,as perception of edge is one of the keys to identify and comprehend the contents of an image.Edge enhancement can be performed in m...Edge enhancement is a fundamental and important topic in imaging and image processing,as perception of edge is one of the keys to identify and comprehend the contents of an image.Edge enhancement can be performed in many ways,through hardware or computation.Existing methods,however,have been limited in free space or clear media for optical applications;in scattering media such as biological tissue,light is multiple scattered,and information is scrambled to a form of seemingly random speckles.Although desired,it is challenging to accom-plish edge enhancement in the presence of multiple scattering.In this work,we introduce an implementation of optical wavefront shaping to achieve efficient edge enhancement through scattering media by a two-step operation.The first step is to acquire a hologram after the scattering medium,where information of the edge region is accurately encoded,while that of the nonedge region is intentionally encoded with inadequate accuracy.The second step is to decode the edge information by time reversing the scattered light.The capability is demonstrated experimentally,and,further,the performance,as measured by the edge enhancement index(EI)and enhancement-to-noise ratio(ENR),can be controlled easily through tuning the beam ratio.EI and ENR can be reinforced by^8.5 and^263 folds,respectively.To the best of our knowledge,this is the first demonstration that edge information of a spatial pattern can be extracted through strong turbidity,which can potentially enrich the comprehension of actual images obtained from a complex environment.展开更多
基金National Natural Science Foundation of China(81627805,81671726,81671851,81827808,81930048)National Key Research and Development Program of China(2016YFC0103803,2017YFA0700401)+3 种基金Hong Kong Research Grants Council,University Grants Committee(25204416)Hong Kong Innovation and Technology Commission(ITS/022/18)Shenzhen Science:and Technology Innovation Commission(CYJ20170818104421564)CAS Scientific Instrument RD Programs(YjKYYQ20170075).
文摘Edge enhancement is a fundamental and important topic in imaging and image processing,as perception of edge is one of the keys to identify and comprehend the contents of an image.Edge enhancement can be performed in many ways,through hardware or computation.Existing methods,however,have been limited in free space or clear media for optical applications;in scattering media such as biological tissue,light is multiple scattered,and information is scrambled to a form of seemingly random speckles.Although desired,it is challenging to accom-plish edge enhancement in the presence of multiple scattering.In this work,we introduce an implementation of optical wavefront shaping to achieve efficient edge enhancement through scattering media by a two-step operation.The first step is to acquire a hologram after the scattering medium,where information of the edge region is accurately encoded,while that of the nonedge region is intentionally encoded with inadequate accuracy.The second step is to decode the edge information by time reversing the scattered light.The capability is demonstrated experimentally,and,further,the performance,as measured by the edge enhancement index(EI)and enhancement-to-noise ratio(ENR),can be controlled easily through tuning the beam ratio.EI and ENR can be reinforced by^8.5 and^263 folds,respectively.To the best of our knowledge,this is the first demonstration that edge information of a spatial pattern can be extracted through strong turbidity,which can potentially enrich the comprehension of actual images obtained from a complex environment.
