Research On Edge Feature Extraction Technology In Optical Scanning Holography System

The digital holography technology makes it possible to accurately capture the threedimensional image of an object.Optical scanning holography is a special non coherent digital holography based on single pixel recording.The information of the object is obtained by optical scanning.A single pixel photoelectric sensor is used instead of the charge coupled device to convert the optical signal into an electrical signal.The system is not limited to the size and resolution of three-dimensional objects.It can capture macro and micro digital holograms,as well as high-precision fluorescent biological specimens.It can be widely used in optical remote sensing,interferometry,biomedicine,topography detection and other fields.Edge feature is one of the most basic features of image.The realization of edge feature extraction can be effectively applied to image segmentation,image recognition,image matching and other fields.The commonly used edge extraction operators are limited by computers and other devices when they extract edge features of images.It is difficult to realize real-time detection.In optical scanning holography,the edge information of an object is obtained directly by optical means.The edge features of objects can be obtained directly by digital reconstruction without complicated algorithm.It can eliminate the time loss caused by calculation.Based on the above reasons,the edge feature extraction technology of optical scanning holography in incoherent mode is studied in this paper.The function of selective edge extraction for twodimensional and three-dimensional objects is realized.Firstly,this paper discusses the theoretical basis and mathematical model of optical scanning technology in detail.Then the edge feature extraction technology in optical scanning technology is emphasized.Then,the double pupil heterodyne scanning system in optical scanning holography is studied.In order to realize the edge extraction of two-dimensional and threedimensional objects in optical scanning holography.Two pupils in the heterodyne scanning system are improved.A selective edge extraction method based on annular pupil is proposed.The influence of the normalized radius in the annular pupil on the edge feature extraction of two-dimensional objects is analyzed.This paper introduces the methods of edge extraction of "single line type" and "double line type".The paper also analyzes the effect of annular pupil in the edge extraction of 3D objects.Then,on the basis of the annular pupil,the defocusing noise in the threedimensional object tomography is analyzed.An optical scanning holography system combining ring pupil and random phase pupil is proposed.The system can remove the influence of defocusing noise on the reconstruction of fault in the edge feature extraction of 3D object.Finally,the application of optical scanning holography system based on ring pupil and random phase pupil in the field of optical encryption is studied.The parallel encryption and decryption of multilayer image are realized.