A Method to Increase the Field of View of an Imaging Optical System

The Y field of view of an off-axis optical system is generally less than 1°. Scholars usually use a freeform surface to achieve a rectangular field of view imaging. However, it adds to the difficulty of processing, testing, assembling, and adjusting, and at the same time has the drawbacks of high manufacturing costs and long processing cycles. In view of the above problems, this paper presents a computational imaging design method for expanding the Y field of view of an off-axis optical system. This method analyzes the aberration characteristics of the optical system, creates a point spread function model based on the wavefront aberration theory and Zernike polynomials, and processes images using a spatial variation deconvolution algorithm. In this paper, we used this method to simulate an off-axis three-mirror optical system with a focal length of 260 mm, the f-number of 2.5, and a field of view of 8° × 1° and compare the images before and after processing. The results show that the processed images have a clear outline, the overall image quality is improved, the field of view is improved to 8° × 6°, and the modulation transfer function of the entire field of view is above 0.4. The off-axis optical system rectangular field of view imaging is realized without using a freeform surface.