Research And Application Of Panoramic Annular Imaging Optical System

Panoramic Annular Lens (PAL) is a special lens with super large Field of View (FOV). It projects a cylindrically panoramic view of 360°around the optical axis to an annular area on a plane. Because of its miniature and convenience, PAL is applied to many areas, such as military, medical and monitoring.PAL has a super large FOV. Therefore, nearly all existing Panoramic Annular optical systems have short focus. However, PAL with short focus cannot satisfy the need of viewing objects far away. In order to solve this problem, we worked over design, manufacture and application of PAL system with long focus comprehensively.In this dissertation, we firstly research into the imaging principle of PAL According to the analysis, we find the importancy of eliminating chromatic aberration, and we propose a new cemented PAL to replace tradional one-piece PAL. Advantage of new cemented PAL is demonstrated by analysis and calculation. A panoramic annular optical system with new cemented PAL is designed and produced.Secondly, we bring in diffractive structure for the sake of simplifying panoramic annular optical system with long focus. Examples indicate that the diffractive structure helps to reduce the aberration of panoramic annular optical system effectively. And the system can be much more simplified by this structure.However, for a single-piece diffractive suface, it is difficult to concentrated light in a wide spectrum to a certain order. To solve this problem, a new Multi-Diffractive Optical Element (MDOE) is proposed to replace ordinary single-piece Diffractive Optical Element (DOE). It is demonstrated by calculation that, this new structure can concentrate over 99.3% light in visible spectrum into +1 order. Prototype of an optical system with a MDOE structure is designed and manufactured. Testing results an analyzed in detail. Suggestions for the next work are proposed.Finally, a new application of panoramic annular stereo optical system is proposed. This system consists of two pieces of PAL and a CCD detector. Principle of this new system is described.Innovation of the dissertation:optical properties of panoramic annular optial system are analysed thoroughly. A universal method of designing panoramic annular optical system is propoed. A new panoramic annular optical system is designed and manufactured. Focal length of this system is 10 times of the existing systems. New cemented PAL is used to replace traditional one-piece PAL. MDOE is brought in to correct the chromatic aberration and to simplify the optical system effectively. Plenty of manufacture and design experience are described in the dissertation. A new panoramic annular stereo optical system is also proposed in this dissertation as an application of PAL.