基于波前编码的扩展景深短波红外成像系统

Wavefront Coding-Based Short-Wave Infrared Imaging System for Extended Depth of Field

短波红外波段具备全天时、全天候成像的优良潜力,借助焦平面探测阵列在现代社会发挥着日益重要的作用。为了解决短波红外成像系统的离焦问题以提升平台适用性,将波前编码技术引入短波红外波段。针对无法配置调焦机构的轻小型短波红外成像系统,在光瞳位置放置三次方型相位板扩展景深。将相位板参数转换为径向坐标系数,利用调制传递函数一致性和图像可恢复性优化该系数。利用640 pixel×512 pixel的短波红外图像仿真波前编码成像性能,通过Lucy-Richardson经典算法还原中间模糊图像。光学设计和图像仿真结果表明,波前编码系统至少在±20倍景深范围内能够有效降低系统对离焦的敏感性,复原图像峰值信噪比最高可达38.5038 dB。

Shortwave infrared(SWIR)band has excellent potential for imaging.Owing to the focal plane detection arrays,SWIR plays an increasingly important role in modern society.Aiming to solve the defocus problem of SWIR imaging and improve its applicability,a wavefront coding system is introduced into the SWIR band.For light and small SWIR imaging,a cubic phase mask is placed at the pupil to extend the depth of field.The phase mask parameter is converted into radial coordinate coefficient,which is optimized by the consistency of the modulation transfer function and image recoverability.Leveraging 640 pixel×512 pixel SWIR images to simulate the wavefront coding system,and the blurred images are restored through the classic LucyRichardson algorithm.The optical design and simulation results show that the wavefront coding system effectively reduces the sensitivity of SWIR imaging to defocus within at least±20 times the depth of field,and the peak signaltonoise ratio of the restored image reaches 38.5038 dB.