消除光学渐晕的FPGA实时校正系统

FPGA real-time correction system for eliminating optical vignettingXie Hong-bo1*, Zhang Yan-kun1, Tian Li-feng1, Fei Qiang1, Xie Xin-wang1,

摘要:

本论文从图像处理的层面消除了折反式光学成像系统中存在的光学渐晕效应。文中采用辐射定标的方式获得光学成像系统的辐射校正系数，并得出辐射校正系数满足二次多项式分布。辐射校正前相机的非均匀性误差为13.2%，校正后非均匀性误差降至3.8%，这说明辐射校正方法大大降低了光学渐晕效应。另外在实时校正系统中，采用二次多项式拟合的方式大大降低了校正系数对系统存储资源的要求。相比于原始校正系数数据量，拟合后的存储数据量减少了约三个数量级。本文中采用的二次多项式拟合的方式可有效改善光学渐晕效应，且更容易在基于FPGA系统部署，具有很强的实用价值。

Abstract:

In this paper, we eliminate the optical vignetting effect in refractive and reflective optical systems with image processing. We use the radiometric calibration method to obtain the calibration coefficient, which satisfies the quadratic polynomial distribution。The non-uniformity error before correcting is 13.2%, and it decreases to 3.8% after correcting, which demonstrates that the method of radiation correction could reduce the optical vignetting effect. In addition, in the real-time correction system, the quadratic polynomial fitting method greatly reduces the requirement of the correction coefficient on the storage resources. Compared with the original correction coefficient data size, the amount of stored data after fitting is reduced by about three orders of magnitude. The quadratic polynomial fitting method is able to effectively eliminate the optical vignetting effect, and it is easier to deploy in FPGA system, which is of great significance.