Satellite vibrations during exposure will lead to pixel aliasing of remote sensors, resulting in the deterioration of image quality. In this paper, we expose the problem and discuss the characteristics of satellite vi...Satellite vibrations during exposure will lead to pixel aliasing of remote sensors, resulting in the deterioration of image quality. In this paper, we expose the problem and discuss the characteristics of satellite vibrations, and then present a pixel mixing model. The idea of mean mixing ratio （MMR） is proposed. MMR computations for different frequencies are implemented. In the mixing model, a coefficient matrix is introduced to estimate each mixed pixel. Thus, the simulation of degraded image can be performed when the vibration attitudes are known. The computation of MMR takes into considera- tion the influences of various frequencies and amplitudes. Therefore, the roles of these parameters played in the degradation progress are identified. Computations show that under the same vibration amplitude, the influence of vibrations fluctuates with the variation of frequency. The fluctuation becomes smaller as the frequency rises. Two kinds of vibration imaging experiments are performed： different amplitudes with the same frequency and different frequencies with the same amplitude. Results are found to be in very good agreement with the theoretical results. MMR has a better description of image quality than modulation transfer function （MTF）. The influence of vibrations is determined mainly by the amplitude rather than the frequency. The influence of vibrations on image quality becomes gradually stable with the increase of frequency.展开更多
卫星振动不仅会引起TDI(Time Delay and Integration)CCD相机像元采样的不规则性,还会引起像元弥散斑空间分布的不一致性,导致图像传递函数(Modulation Transfer Function,MTF)产生空间变化,从而制约高分辨率图像振动复原质量。本文从...卫星振动不仅会引起TDI(Time Delay and Integration)CCD相机像元采样的不规则性,还会引起像元弥散斑空间分布的不一致性,导致图像传递函数(Modulation Transfer Function,MTF)产生空间变化,从而制约高分辨率图像振动复原质量。本文从卫星振动对TDICCD相机推扫成像采样过程的作用机理出发,结合理论推导与仿真研究,得到了平台振动引起的图像空间移变降质及表征方法。然后在振动复原模型的基础上,推导得出MTF空间移变降质对复原处理误差的影响,并基于实际卫星图像开展了复原实验。实验结果表明:当振动所致图像MTF空间移变降质小于15%时,复原处理后的图像与理想图像的结构相似度优于0.95,而且处理误差所导致的图像失真不影响判读质量。展开更多
文章以某高分辨率遥感卫星为背景,开展基于微振动对成像质量影响的CMG(controlled moment gyro,控制力矩陀螺)微振动抑制方法研究,首先分析微振动的方向、振幅、频率对成像质量的影响规律,提出微振动抑制不仅应考虑结构的动力学特性,而...文章以某高分辨率遥感卫星为背景,开展基于微振动对成像质量影响的CMG(controlled moment gyro,控制力矩陀螺)微振动抑制方法研究,首先分析微振动的方向、振幅、频率对成像质量的影响规律,提出微振动抑制不仅应考虑结构的动力学特性,而且应该根据微振动对成像质量的影响规律开展针对性设计;然后以某型号CMG为例,建立包括结构有限元模型、扰振源模型、隔振器模型在内的微振动分析模型,得到100 Hz频率下振动响应随隔振器弹性模量的变化规律,并在此基础上,结合隔振系统的频率要求等约束条件对隔振器参数进行优化。仿真结果表明:优化后隔振器三方向的隔振效率都在50%以上,提高了高分辨率遥感卫星的成像质量,可为后续微振动抑制研究提供参考。展开更多
基金supported by the National Basic Research Program of China(Grant No.2013CB329202)the Basic Industrial Technology Project of China(Grant No.J312012B002)
文摘Satellite vibrations during exposure will lead to pixel aliasing of remote sensors, resulting in the deterioration of image quality. In this paper, we expose the problem and discuss the characteristics of satellite vibrations, and then present a pixel mixing model. The idea of mean mixing ratio （MMR） is proposed. MMR computations for different frequencies are implemented. In the mixing model, a coefficient matrix is introduced to estimate each mixed pixel. Thus, the simulation of degraded image can be performed when the vibration attitudes are known. The computation of MMR takes into considera- tion the influences of various frequencies and amplitudes. Therefore, the roles of these parameters played in the degradation progress are identified. Computations show that under the same vibration amplitude, the influence of vibrations fluctuates with the variation of frequency. The fluctuation becomes smaller as the frequency rises. Two kinds of vibration imaging experiments are performed： different amplitudes with the same frequency and different frequencies with the same amplitude. Results are found to be in very good agreement with the theoretical results. MMR has a better description of image quality than modulation transfer function （MTF）. The influence of vibrations is determined mainly by the amplitude rather than the frequency. The influence of vibrations on image quality becomes gradually stable with the increase of frequency.
文摘卫星振动不仅会引起TDI(Time Delay and Integration)CCD相机像元采样的不规则性,还会引起像元弥散斑空间分布的不一致性,导致图像传递函数(Modulation Transfer Function,MTF)产生空间变化,从而制约高分辨率图像振动复原质量。本文从卫星振动对TDICCD相机推扫成像采样过程的作用机理出发,结合理论推导与仿真研究,得到了平台振动引起的图像空间移变降质及表征方法。然后在振动复原模型的基础上,推导得出MTF空间移变降质对复原处理误差的影响,并基于实际卫星图像开展了复原实验。实验结果表明:当振动所致图像MTF空间移变降质小于15%时,复原处理后的图像与理想图像的结构相似度优于0.95,而且处理误差所导致的图像失真不影响判读质量。
文摘文章以某高分辨率遥感卫星为背景,开展基于微振动对成像质量影响的CMG(controlled moment gyro,控制力矩陀螺)微振动抑制方法研究,首先分析微振动的方向、振幅、频率对成像质量的影响规律,提出微振动抑制不仅应考虑结构的动力学特性,而且应该根据微振动对成像质量的影响规律开展针对性设计;然后以某型号CMG为例,建立包括结构有限元模型、扰振源模型、隔振器模型在内的微振动分析模型,得到100 Hz频率下振动响应随隔振器弹性模量的变化规律,并在此基础上,结合隔振系统的频率要求等约束条件对隔振器参数进行优化。仿真结果表明:优化后隔振器三方向的隔振效率都在50%以上,提高了高分辨率遥感卫星的成像质量,可为后续微振动抑制研究提供参考。
