Calculation And Image Simulation Of Infrared Radiation Of Cloud Background

Cloud is an important part in sky background. IR system will receive the radiation as a disturbance from the clouds which affects its performance when it detects targets in the sky. For the purpose of deducing the disturbance caused by cloud background and developing IR Imaging System with high efficiency, the radiation properties and image simulation of the cloud background need to be concerned.The paper starts with the theory of physical and optical properties of the cloud, and makes a study of the radiation of the cloud and cloud-radiation feedback. The transmission function in cloud and the formula for calculating the radiation of the cloud are given. The radiation of the cloud background is affected by a number of factors. These factors and the methods for radiation calculation of these factors are all studied in this paper. The calculation of spectral and wave band radiance of the cloud background under typical conditions is carried out on computer. Focused on the results of the calculation, the analysis of the cloud radiative properties is made. As for the simulation of infrared image of the cloud background, we generate a 2-D data field by fractal method and project it to a cloud depth field. Then the radiance field of the cloud background is calculated based on the theory model. At last the radiance field is converted to a grey image and visualized.