| Precision optical measurements are made using straight-line propagation of light in the atmosphere,but atmospheric conditions often cause disturbances in optical measurements,causing image point drift in camera imaging.In this paper,the influence characteristics of airflow disturbance on precision optical measurement and the method of disturbance elimination in atmospheric environment are studied.In many fields,the influence of airflow disturbance has been studied,but there is no better solution in the field of photogrammetry.In this paper,the influencing factors of airflow disturbance are firstly explored,and the influence of atmospheric refractive index and turbulence on airflow is determined.Then,the degree of influence of the atmospheric refractive index on the disturbance of the airflow is analyzed in depth.By studying the relationship between the atmospheric state parameters and the atmospheric refractive index,the effects of atmospheric structure,pressure and temperature on the refractive index are obtained.Then a lot of basic experiments were carried out to determine the way the disturbance frequency affects the image point drift.The experiment also verified the influence of airflow disturbance on the target imaging under different conditions and the distribution characteristics of atmospheric disturbance.Then the mechanism of the airflow disturbance in the imaging process of the camera is studied.By analyzing the influence of the airflow disturbance,it is found that the constraints provided by the single camera cannot solve the low frequency disturbance in the atmosphere.In this paper,we first attempt to solve the disturbance error in the atmosphere by constructing the atmospheric layered refractive index model.The atmospheric layered refractive index model with height as a variable is constructed by the relationship between atmospheric refractive index and atmospheric state.This model needs to take the camera measurement data of different heights as the initial value,and construct an accurate atmospheric layered refractive index model by fitting the atmospheric layered refractive index model with the measured initial value.Then the simulation experiment was carried out using the meteorological platform data.The experimental results show that the model and the actual data fit well,but there is a certain degree of deviation in the area near the ground and outside the troposphere.Therefore,the paper also studies the problem of solving the airflow disturbance near the ground.For airflow disturbances near the ground,the disturbance is eliminated by constructing a camera system with constraints.The visual imaging system can effectively solve the disturbance error between the cooperative targets by using the system constraints.The fixed camera-optical imaging experiment results show that the visual imaging system can effectively eliminate the influence of the airflow disturbance in the precision optical measurement between the cooperative target points.For the elimination of non-cooperative target airflow disturbances,ordinary parallel imaging systems are difficult to complete.The large field of view of the warp and weft camera can effectively measure the data of large angle of view in the atmosphere,and proposes to construct an observing system based on the warp and weft camera.The system is easy to measure and can measure multiple sets of data at a time.Taking advantage of the ability of the warp and weft camera to rotate,a method for optimizing the optical measurement imaging of non-cooperative points under atmospheric disturbance based on the latitude and longitude camera vision imaging system is proposed.By constructing a measurement relay point between the target point and the observation point,an illuminating imaging system between the observation point and the relay point is constructed,and the atmospheric disturbance distance from the observation point to the target is effectively reduced.The experimental results show that the attenuation effect of the system on the atmospheric disturbance at the target point is stronger as the distance between the relay point and the non-cooperative target point decreases. |
