Cirrus Image Processing And Scattering Analysis

It is studied in the dissertation that the cirrus scattering radiation effects on detecting of targets from earth to high space. First, cloud maps of sky-background which were shot and collected were processed by using threshold segmentation method. Second, the scattering radiation of cirrus was studied.The work of observing and shooting the clouds in the high altitude from the ground bases need to operate continuously, a number of cirrus maps were collected, and characteristics of scattering radiation of the cirrus were analyzed precisely. A suit of experiment instruments was installed by author of the dissertation and the work group, with which the cloud data including summer, autumn and winter of the Chengdu area were collected from June 2006 to January 2007. A combined method of alternating and average bright threshold has been put forward that was optimized to segment cloud and sky-background. To establish databases of cloud, with the facility experiment methods and to apply combined method of the segment cloud and sky-background have both not been reported. It is also a new ideal that Monte Carlo method was used to model cirrus'multiple scattering in the dissertation.The main achievements in this dissertation were listed as follows.1. Cloud maps of sky-background were provided in the same position and in the same time every day. The cloud data including summer, autumn and winter of the Chengdu area were collected from June 2006 to January 2007.2. It was found that additional brightness of sky was added by analyzing cirrus maps with its scattering radiation. The relation between scattering radiation and wavelength were founded by processing images of cloud in visible light.3. It was given that the difference of the sky radiation luminance between the situations of the cloud and the cloud-free in their gray histograms. The combined method with the alternating and average bright threshold is optimal compared to the methods of background cutting and alternating in the segmentation of the cloud and the sky-background4. The spectra distribution of the cloud (including cumulus, stratus and cirrus) droplets was simulated,the original data of the particles were from LOWTRAN. The relationship between ice water content and cirrus kinds , particles'scales and temperature were analyzed. The calculating of cirrus was simple with the T-matrix theory, which was used to analyze scattering of single particle of ice-crystals.5. Optic traits of the cloud were simulated such as optical thickness and transmissivity. Monte Carlo method was used in modeling cirrus'multiple scattering. The albedos were calculated on single scattering and multiplying scattering of cirrus.