Research On Lens-Combined Modulation Wavefront Coding

As is known to all,due to the large depth of field optical imaging system can obtain more information on object space and can reduce the system aberration caused by defocus to some certain,large depth of field has been one of optical designer's goal.On account of the unique advantages,Wavefront coding technique has received attention since put forward by scholars and become one of the forefront of technology in the depth of field continuation method.Wavefront coding technique modulates the system light by using phase mask on pupil.After modulation,the point spread function(PSF)and optical transfer function(OTF)of imaging system is not sensitive to defocus,so as to make the system has similar imaging features in a wide depth of field.However,the OTF becomes lower after modulation so that detector collected a series of coding images with consistent fuzzy in different image planes.Then digital image processing techniques is used to restore clear images of decoded images,ultimately achieve the goal of the depth of field continuation.This technique greatly expanded the depth of field without reducing the luminous flux,having obvious advantages compared with the traditional depth of field continuation techniques and having broad application prospects in various fieldsAt present,the wavefront coding technique research mainly involves the phase mask surface,decoding algorithm,application field,and many other aspects.In the encoding phase,coding role always provided by a single piece of phase mask which has certain limitations.In terms of decoding,a variety of image restoration algorithm has been used for decoding of wavefront coding system.However,with the continuous development of digital image processing technology,the decoding algorithm has the possibility of were increased in decoding quality and decoding speed.This article main research content is as follows:Firstly,the Lens-combined Wavefront coding concept is put forward based on traditional wavefront coding theory,making the coding is not limited to a single piece of mask,and let multiple components of the system involved in coding process.This technique This technique saves focus aberration correction process in the traditional design of optical system,which can gain not only large depth of field,but also offer a new optimal design method for many systems having the difficulty in focus aberration correction.Then,this article analysis the principle of Lens-combined modulation wavefront coding in the geometric Angle of light modulation,and proves the feasibility of this method by using ray tracing.In addition,the article also puts forward three suitable optimization theory and design method for Lens-combined modulation wavefront coding system.Secondly,this article studies the decoding algorithm in detail,which analysis the decoding method based on the PSF and puts forward rapid space decoding algorithm;Compared with common decoding algorithm by simulation experiment,the new decoding algorithm has been confirmed greatly improving the decoding speed in the case of ensuring the quality of decoded images.In addition,in order to integrate a variety of algorithms and reach real-time imaging of wavefront coding system,this article develops a real-time decoding program based on Open Cv.Thirdly,based on Lens-combined modulation wavefront coding technology,developed a large depth of field large aperture optical imaging system.Through the experiment by comparing with the traditional system,it is proved that the Lens-combined modulation wavefront coding technology has obvious advantages than the traditional system in aperture and depth of field.Also it is proved that Lens-combined modulation wavefront coding technique can not only expand the system depth of field,but also simplifies the system design steps and reduce the design difficulty,and also provides a new method for optical system design which has many aberration correction difficult.Fourthly,based on the wavefront coding system imaging quality improvement,two method are proposed based on apodization and imaging quality improvement method of super-resolution,respectively in imaging coding and digital image processing.Experimental results show that the above two methods can effectively improve the image quality of wavefront coding system.