Research On Optical System Design Of Wide Area High Resolution Camera

Wide area high resolution imaging system can obtain a wider field of view(FOV)and identify more target details,which has been widely used in security monitoring,aerial reconnaissance,three-dimensional target detection and other fields.However,for traditional single lens imaging systems,the FOV and resolution are restricted by each other.In order to obtain high resolution imaging with wide field of view,wide FOV lens with complex structure and large size image sensors both need to be developed which will increase the design difficulty and manufacturing cost.Combining the monocentric system's wide FOV information collection ability and the aberration correction ability of the microcamera,the monocentric multiscale imaging technology has broken the limitation of the scaling laws for traditional lens system and solved the contradiction between the wide FOV and the high resolution.It is one of the effective ways to achieve wide FOV high resolution imaging nowadays.In this paper,based on the principle of monocentric multiscale,the design method of wide area high resolution camera optical system was studied.The key properties of this system are verified by using the scaled prototype.The main research works are as follows:Firstly,the scaling law for lens system was deduced.It verified that multiscale system can achieve wide FOV with high resolution imaging.The principle of monocentric multiscale design was studied.Based on this principle,the model of monocentric multiscale optical imaging system was established.Then the overlap of the field of view of adjacent microcameras was analyzed.And the corresponding packing strategy of microcameras on the spherical surface was studied.According to the above analysis and studies,the internal relationship between the parameters of monocentric multiscale imaging system was obtained.Those works laid the foundation for the subsequent optical system design.Then,the optical design of the monocentric objective lens and the secondary microcamera lens were completed with corresponding image quality evaluations.Then further optimizations,tolerance analysis and thermal analysis of the entire multiscale optical lens were carried out.In result,a monocentric multiscale optical lens which has good image quality and can be fabricated easily was designed.Fellowingly,the Multi-Configuration was used to arrange the array of microcameras on the spherical surface.It constructed a wide FOV high resolution camera system model which contained a monocentric objective and 17×15 microcameras and had 90??67.5? field of view.After analyzing the imaging quality of the camera system in different sub channels,it was found that the deviations of the image quality and distortion among different sub camera channels in different fields of view were very small.For all imaging sub channels,the MTFs in the spatial frequency of 112lp/mm were higher than 0.4 and the distortions were less than ± 0.4%.This indicated that the multiscale optical lens designed in this paper had good imaging quality in the whole field of view.Finally,a 3×3 scaled prototype was used to form the experimental system.And several key indicators which can affect the imaging capability of this optical system were tested and analyzed.The test results showed that the imaging quality and distortion of this optical system designed in this paper met the design requirements.And the overlapping area of the adjacent image sensors could also satisfy the requirements of image splicing.These test results verified the rationality and correctness of the optical design in this paper for the wide area high resolution camera.In summary,the imaging performance of each sub aperture in the imaging system met the requirements of building wide area high resolution camera.It laid the foundation for the subsequent prototype development.