A Study Of Moncentric Wide Field Of View And High-resolution Imaging

Today’s high-resolution cameras capture images with pixel counts in the tens of millions, and the recent trend in image sensor resolution seems to suggest that we will soon have cameras with billions of pixels. The resolution of a camera system determines the fidelity of visual features in captured images. Higher resolution implies greater fidelity and, greater accuracy when performing automated vision tasks, such as object detection, recognition and tracking. For a traditional optical imaging system, large field of view and high resolution is a very prominent contradiction. Wide field of view requires the optical imaging system with a small focal length, while high-resolution requires a long focal length. Solving this contradiction has great significance to the development of next generation of optics remote sensing, warning and controlling system. However, the resolution of any camera is fundamentally limited by geometric aberrations. In addition, increase in the field of view will usually lead to the increase in volume and mass of the optical imaging system, therefore, the problem in the camera design process is how to make the structure compact and lightweight simultaneously to ensure a wide field of view and high-resolution imaging.We derive a scaling law that shows that, by using computations to correct for aberrations, we can create cameras with unprecedented resolution that have low lens complexity and compact form factor. In this paper, we present a moncentric camera with wide field of view and high-resolution for gigapixel imaging, which consists of two levels of optical system shared by several small planar sensors. This architecture is spherical symmetry and gets 120°continuous field of view. The major work of this paper is as follows:(1) Based on the mathematical formulas between imaging resolution and scaling factor M of the traditional optical imaging system and the computation imaging system, a scaling law to traditional optical imaging system and an analytic scaling law to computation imaging system are derived severally and compared;(2) Due to the properties of the ball lens, moncentric optical systems are designed by using different materials spherical surfaces, which with rotational symmetry has no off-axis aberration such as longitudinal chromatic aberration, astigmatism, coma. And the modulation transfer functions are optimized to reduce aberration by ZEMAX software;(3) A secondary optical system is designed with several identical relay microlens to correct the residual aberration and divide the wide field of view equally, which can adjust the aberrations of different field of view;(4) Two moncentric cameras with design parameters are presented in this paper, and the two-dimensional images, the diagrams of MTF and spatial frequency and the aberration characteristic curves are also given by using ZEMAX software.