Aresearch On Design Of High Resolution PAL-based Panoramic Imaging System

Panoramic imaging technology started at US Department of Defenseon1980s, to meet the requirements of the military target detection with widefield and all-weather. Now in addition to the military field, the technology has beenused in vast applications such as panoramic surveillance, machine vision, medicalendoscopic and pipeline detection, etc. In several mainstream panoramic imagingtechnologies, panoramic annular lens (panoramic annular lens, PAL for short)imaging system has great application advantage due to high integration, compactstructure and feature of miniaturization. About this technology most of the studiesare focused on the PAL-based imaging system with short focus, which has a maturedesign and application. In view of the applications with long distance resolution,Telephoto PAL imaging system is needed, which has a difficult structure design,therefore, it become new research hotpot. The following is the main work of thispaper:1. The development history and research status of several mainstream panoramicimaging technologies is introduced. Due to the advantages of panoramic annular lens(PAL) imaging, meanwhile combining the current research hotspot of this technology,the research topic of this paper is proposed, which is the research on design for longfocus, high resolution PAL-based imaging system.2. The optical properties of PAL-based imaging system from these aspects ofimaging method, optical structure, object-image relationship, depth of field, pupilcharacteristics and image plane illumination are analysed,.3. In terms of the system structure design, design method of the telephoto PALand the relay lens group is studied. The modeling and optimization of both the initialstructure is discussed, and the aberration compensation and the optical pathconnection between the two lens group.is analysed.4. A design of high resolution PAL-based imaging system which has a focallength of8mm, F/#of3.2, lateral view of40°-100°is completed. the determination oftechnical parameters, the initial structure modeling, aberration correction and the imaging result analysis these design process is introduced. The final design of thesystem has a high performance, whose whole view MTF at80lp/mm are higher than0.5, like illumination uniformity of image plane and f-θ imaging features is good.5. With the multilayer diffractive optical element (MLDOE) has increasinglyimportant application in the telephoto and complex optical system, so the applicationof MLDOE in telephoto PAL imaging system is introduced here. Firstly the designand relief depth optimization of MLDOE with high diffractive efficiency is studied,and then bring in MLDOE in the relay lens group. Finally PAL-based imaging systemwith the same performance compared with previous design is obtained. whosestructure is greatly simplified and the image quality is close to the diffraction limit.