Infrared Panoramic Imaging System Design

Infrared panoramic imaging system has the advantages in both infrared and panoramic imaging. Considering the characteristics of wavelength, infrared imaging can be applied in all conditions with thermal infrared radiation, which could effectively tackle the challenges for optical imaging instruments made by special complicated scenes. By the effective design of optical instruments, panoramic imaging can achieve a large field of view and 360°panoramic imaging. Infrared panoramic system has been widely used in infrared panoramic surveillance, detection of underground pipes, medical endoscopic and many other fields. It has become a popular research direction in the large field of view. Domestic and foreign investigators have done a lot of researches and explorations on the infrared panoramic imaging, and have achieved some useful results. However, not so many infrared panoramic imaging system can meet the practical needs. Thus, undoubtedly, it is of great significant to invent and design the infrared panoramic imaging system that can be meet the practical needs.Based on both Chinese and foreign references, this paper introduces the background and current investigations of panoramic imaging systems; introduces the development and application of infrared imaging materials; analyzes the universal character of panoramic imaging system and the method of achieving panoramic imaging; and selecting analyzes the catadioptric panoramic imaging. The following are the main work in this paper:1. Using the linear relationship between the tangent angle of incidence and the reflection angle tangent as the condition of eliminating distortion replace the linear relationship between the scene coordinates and the image plane coordinates, a improvements based on the references of [9, 10] has been made to design catadioptric omnidirectional system with undistorted imaging for horizontal scene and cylindrical scene. The designed system can not only meet the distortionless imaging demands of the system horizontal Scene and the cylindrical scene, but also have a certain depth of field for being conductive to get a Panoramic stereo imaging system. Then the theoretical of the design has been verified by a example.2. Based on the reference of [15] and the use of CODE-V as the computer simulation tool, a new compact structure of small infrared panoramic lens which have a wave band 3～5μm was completed. Compare to the design of the original references, the difficulty of processing the lens was reduced by setting the model's two transmission surface and two reflection surface to sphere, and the optimizing of the relative aperture can improve system's sensitivity and resolution, and the system aberrations was effectively balanced by setting asphere and the diffraction surface in relay system. The lens had a wave band 3～5μm, a field of view±55°~±100°, F-number1.3, focus -0.53mm, overall length 64.5mm, and the resolution limit of the lens was only 6.3μm. The analysis of the athermalization indicated that, the optical system canwork steadily with high optical quality in the temperature range of -20℃～60℃.3. Based on the references of [15,16] and the patent US6611282, another infrared panoramic lens was completed. Compare to the design of the original references, the system in this paper has a first convex Reflector and a second concave Reflector, such a structure assemble not only retain the advantages of the original design, but also give a solution of the limit of the field view. The final results indicate that: in the 3～5 micron infrared wave band, the system has the panoramic field of±50°～±100°, and also has a total length of 151mm, a value of the f/number of 1.5, and a back focal length of 26.68mm, all of this meets to the application of the infrared panoramic surveillance and underground pipeline detection and other special fields.