Design And Integration Of The Curved Multi-focusing Compound Eye Imaging System

With the rapid development of electronic surveillance,mobile phone photography,image recognition,and artificial intelligence,different applications have placed higher requirements on imaging systems.Optical imaging systems are developing towards miniaturization,compactness,and integration.Traditional optical imaging systems usually use lenses to capture the image.The more the number of lenses,the larger the volume of the optical system and the more complex the structure,which makes it difficult to integrate with the other miniaturized systems.Inspired by natural compound eyes in nature,people study bionic curved compound eyes on the basis of the development of microlens arrays.The curved compound eye has a large field of view,a large depth of field,and a compact structure.It has high sensitivity in capturing the motion information of high-speed moving objects.In the past,researchers mainly focused on the fabrication process of compound eyes,and proposed a series of manufacture methods,such as laser direct writing,photoresist reflow,wet etching,etc.Based on the development of theses researches,Our laboratory to integrate a complete compound eye imaging system and develop mature applications.The complete curved compound-eye imaging system includes three sub-systems: the curved compound eye lens,opto-mechanical structure,and backend image processing module.The innovative research content and work of this thesis are related to these three subsystems,namely:(1)Design and simulation of curved compound eye camera: The design includes two parts.one part is the structure design of the non-uniform curved compound eye,the compound eye lens parameters are determined by the design,and the defocusing phenomenon is corrected.The other part is the camera packaging structure design,including the lens holder,lens mount,side wall and base.It has to meet size requirements and integration requirements,as well as various assembly and adjustment requirements.The simulation is mainly divided into PDMS negative pressure deformation simulation and optical simulation.PDMS deformation simulation can find the linear relationship between the deformation and the negative pressure value,which determines the theoretical basis of lens design.Optical simulation verifies the feasibility of the design in principle and optimizes it.(2)Fabrication of the curved compound eye: Based on the MEMS(MicroElectro-Mechanical System)technology,this paper proposes two design and rapid fabricating methods for microlenses.One is to use hot press to achieve planar microlens arrays with the same sagittal height and different diameters,and then the planar microlens array is transfered into the curved compound eye.The other is to use two gas-assisted to fabricate the curved compound eye lens with different sag heights and diameters.These two methods combine traditional lithography,soft lithography with hot pressing and gas-assisted process,which can control the radius of the ommatidia precisely,and improve the efficiency of fabricating the curved compound eye.(3)Back-end image processing: One of the basic characteristics of compound eyes is the large field of view,so one of its applications is large field of view imaging.After the compound eye imaging system is calibrated,the images of each ommatidium is stiched and fused.Due to the large amount of data,the long processing time and its high sensitivity to the moving object,the curved compound eye imaging is combined with current hot artificial intelligence to study the rapid recognition of targets.The curved compound eye imaging system is also a multi-eye vision,which can simultaneously feedback three-dimensional information.