Research On Mixed Pixel Model In Remote Sensing Imaging Simulation

The rapid development of remote sensing satellites provides a large number of information for remote sensing data users.Full range simulation of high resolution satellite imaging is the main means to evaluate the effect before satellite being launched,and mixed pixel simulation is the important part of remote sensing imaging simulation.With the improvement of spatial resolution,the degree of surface recognition is higher,so that the mixed pixels caused by heterogeneous exist universally.And in the high resolution remote sensing image,factors such as atmospheric scattering and proximity effects can also lead to the appearance of mixed pixels.In the research of satellite imaging system simulation,the modeling of mixed pixels is one of the focuses.Based on the above background,the paper conducts corresponding research on mixed pixel problem.First of all,the relevant research was carried out to solve the problems of heterogeneous mixed pixel at based on zero stadia image.Considering the effects of three-dimensional target geometric features,shadows during lighting,and background radiation on mixed pixels,the traditional linear model is improved.The experiments have shown that the contribution of each material to mixed pixels is not only related to the area ratio,but also related to the distance of the end element in the field of view.The mixture reflectance of different regions in the field of view is obtained by the design experiment,using the least-squares method to fit the weights of the different regions,and the mixed pixel is modeled.It is proved by experiments that the improved model established by different weight coefficients is more accurate for mixed pixel simulation.Secondly,the theoretical analysis of the mixing problem in the atmospheric transmission process is mainly divided into atmospheric transmission and atmospheric cross radiation effects.The attenuation and path radiation effects in atmospheric transmission can be calculated by the corresponding transmittance and path radiation through the radiation transfer software.The Monte Carlo method can be used to calculate the weight of the cross radiation in the pixel.Finally,six different regions are selected for zero stadia reflectance images of ground resolution decimeter level,a hybrid pixel linear model and an improved model were used to calculate the combined radiance values of the mixed region at 10m resolution.Then,the atmospheric transmission effect was added to obtain the radiance value of the entrance pupil of the satellite,and compared with the satellite real shot map results.The results show that the traditional linear model simulation error is within 15%,and the improved model simulation error is within 10%.The simulation accuracy of the improved model is higher.The improved linear hybrid pixel model proposed in this paper can calculate the integrated radiance of three-dimensional objects and heterogeneous background in the field of view,and discuss the two mixing effects of the pupil in the atmosphere,which provides a basis for the full link simulation technology of high resolution satellite imaging.And the zero horizon reflectivity image obtained by the method proposed in this paper can be used as a zero horizon standard diagram in the range of error and uncertainty,and has a reference value in the high resolution satellite imaging simulation.