The main effect of atmospheric turbulence on the image
In the atmosphere, the direction and magnitude of the speed of motion at any point change irregularly at any time, resulting in irregular motion of each atmospheric molecular group relative to the overall average motion of the atmosphere. This phenomenon is called atmospheric turbulence.
Atmospheric turbulence can cause random changes in the refractive index at any location in the air, causing the light beam to propagate in the same path of the air but have different refractive indexes, making the received signal flicker. Caused by turbulence
Where R is the transmission path length, D / 2 is the receiving aperture, z is the height from the ground, and Cn2 is the turbulence intensity. From equation (1), it can be seen that when the intensity of turbulence is very small or the transmission path is very short, the influence is negligible. But there is usually strong atmospheric turbulence outdoors. When the transmission path is long, it will cause strong flicker in the received signal. Mainly manifested as random flashing of signal strength and location. 2nC
The analysis of the impact of atmospheric turbulence on the image can be divided into two aspects: time domain and space domain. In the time domain, atmospheric turbulence causes the received signal strength to randomly fluctuate with time, resulting in images with different brightness collected at any time. When the receiving field of view is relatively large, it appears as uneven brightness of various parts of the image itself, similar to lighting Unevenly captured images. The influence of the airspace is mainly manifested by the random drift of the light beam caused by turbulence, which will cause the jitter of the image point and cause the entire image to randomly drift.
Correction of image distortion caused by atmospheric turbulence
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