大气湍流效应是严重影响航空光电侦察系统图像质量的重要因素之一。从大气湍流参数描述出发,研究了大气湍流对光学系统成像质量的影响机理,分析了大气湍流影响光学系统调制传递函数(modulation transfer function,MTF)的影响因素,建立...大气湍流效应是严重影响航空光电侦察系统图像质量的重要因素之一。从大气湍流参数描述出发,研究了大气湍流对光学系统成像质量的影响机理,分析了大气湍流影响光学系统调制传递函数(modulation transfer function,MTF)的影响因素,建立了大气湍流影响光学系统成像MTF的理论模型。仿真结果表明,在大气湍流影响下,光学系统光瞳口径与大气相干直径的比值对光学系统成像MTF影响较大。通过光学系统地面外场实验图像测试对比,验证了实际光学系统受到大气湍流影响后的成像MTF理论模型。研究结果可为大气湍流影响下的航空光电侦察系统设计及提升其成像质量提供理论支持。展开更多
The visibility of the underwater image is reduced due to the backscattering and signal attenuation, especially in highly turbid media. In this paper, we propose a polarization-based underwater image restoration method...The visibility of the underwater image is reduced due to the backscattering and signal attenuation, especially in highly turbid media. In this paper, we propose a polarization-based underwater image restoration method using logarithmic transformation and dark channel. Logarithmic transformation is first performed while maintaining the degree of polarization of the scene to increase the details of the images. Then we calculate the backscatter value through dark channel to estimate the degree of polarization of backscatter. The restored image can be obtained by the polarimetric recovery method. The experimental results illustrate the capabilities of the proposed method.展开更多
文摘大气湍流效应是严重影响航空光电侦察系统图像质量的重要因素之一。从大气湍流参数描述出发,研究了大气湍流对光学系统成像质量的影响机理,分析了大气湍流影响光学系统调制传递函数(modulation transfer function,MTF)的影响因素,建立了大气湍流影响光学系统成像MTF的理论模型。仿真结果表明,在大气湍流影响下,光学系统光瞳口径与大气相干直径的比值对光学系统成像MTF影响较大。通过光学系统地面外场实验图像测试对比,验证了实际光学系统受到大气湍流影响后的成像MTF理论模型。研究结果可为大气湍流影响下的航空光电侦察系统设计及提升其成像质量提供理论支持。
基金This work has been supported by the National Natural Science Foundation of China(No.61805199)the Natural Science Foundation of Shaanxi Province,China(No.2018JQ6065)。
文摘The visibility of the underwater image is reduced due to the backscattering and signal attenuation, especially in highly turbid media. In this paper, we propose a polarization-based underwater image restoration method using logarithmic transformation and dark channel. Logarithmic transformation is first performed while maintaining the degree of polarization of the scene to increase the details of the images. Then we calculate the backscatter value through dark channel to estimate the degree of polarization of backscatter. The restored image can be obtained by the polarimetric recovery method. The experimental results illustrate the capabilities of the proposed method.
