正弦振动对航空相机成像影响的分析与验证

Abstract

The imaging resolution of aerial camera is limited by vibration during exposure. Dynamic modulation transfer function is used to study the impact of the sinusoidal vibration on imaging. Modulation transfer function (MTF) of high-frequency and low-frequency vibrations are analyzed through the calculation method based on spatial domain. When exposure time is not equal to an integer multiples of the vibration cycle, the impact of high-frequency vibrations on image quality is also random, but the randomness is less apparent than low-frequency vibration. The fast steering mirror is used to simulate vibrations, complementary metal oxide semiconductor (CMOS) sensor is used to capture images, wavelet transform is used to extract high frequency information. Exposure time is set to 20 ms, when the vibration frequency is 50 Hz, the fluctuation range of high-frequency information is only 0.0582104, which can be ignored compared with the total number of high-frequency information. When the vibration frequency is 15 Hz, the fluctuation range is 0.6233104 and randomness is obvious. But when the vibration frequency is 65 Hz, the fluctuation range is 0.1245104 and randomness is not obvious. By the correspondence between high-frequency information and MTF, the correctness of theoretical analysis is proved. On the basis of theoretical analysis and experiments, the general conclusion of sinusoidal vibration's effect on imaging is summed. This conclusion can not only be used to analyze the design of the imaging system structure, but also can be applied to image deblurring.