Design of a compact dual-channel panoramic annular lens with a large aperture and high resolution

We propose a compact dual-channel panoramic annular lens (PAL) with a large aperture and high resolution to solve three major shortcomings of conventional PAL systems: resolution, imaging quality, and compactness. Using polarization technology, the system integrates two optical channels to eliminate the central blind area. Using our PAL aperture ray-tracing model, the large aperture PAL system with a low F-number of 2.5 and a diameter ratio of 1.5 is realized. The field of view (FoV) of the front channel is 360^∘×(0^∘-45^∘), and the FoV of the side channel is 360^∘×(45^∘-100^∘). Both channels apply Q-type aspheres. The Airy radii of the front channel and the side channel are 1.801 and 1.798 µm, respectively. It indicates that they match the 1.8 µm pixel sensor and can form a great image on the same sensor. The modulation transfer function at 157 lp/mm is greater than 0.4 over the entire FoV. The F-θ distortion is less than 5%, and the relative illuminance is higher than 0.78 in the two channels. The excellent imaging results prove the feasibility of our PAL design method and the advantages of the compact dual-channel PAL system for space-constrained scenes.