基于模糊纹理光谱的全天空红外图像云分类  

Cloud Classification of the Whole Sky Infrared Image Based on the Fuzzy Uncertainty Texture Spectrum

作　　者：孙学金[1,2] 刘磊[2] 高太长[2] 赵世军[2] 刘剑[2] 毛节泰[1] 

机构地区：[1]北京大学物理学院,北京100871 [2]解放军理工大学气象学院,南京211101

出　　处：《应用气象学报》2009年第2期157-163,共7页Journal of Applied Meteorological Science

摘　　要：为了对全天空红外测云系统获得的红外图像进行云类自动识别,提出了基于模糊纹理光谱结合云物理属性的全天空云类识别方法。首先根据不同滤波窗口的模糊纹理光谱图像特征,确定了滤波窗口大小,然后通过分析不同天空类型下的FUTS谱(fuzzy uncertainty texture spectrum)以及同一种天空类型下的FUTS谱,考察了FUTS进行云类识别的适用性,最后利用最小距离分类法和云基本物理属性对全天空红外图像进行了分类测试。在200个测试样本中,层状云、积云、高积云、卷云和晴空的识别率分别为100%,100%,90%,100%,100%,平均识别率达到98%。基于模糊纹理光谱的云分类算法对单一云空具有很好的分类效果,可进一步应用于全天空红外图像的云分类识别。Clouds play an important role in the earth radiation budget and climate change. Their shape, size, distribution and movement indicate the condition of the atmosphere. Nowadays, cloud amount and cloud height are collected by means of both satellites and ground-based instruments. Satellite cloud images pro- vide global coverage, and these data are used widely in weather forecast. Ground-based cloud images are very local ones which contain more details of clouds. Cloud classification using satellite images has been done for many years, while the study of ground- based cloud classification is still underway. A method using fuzzy uncertainty texture spectrum and essen- tial information in cloud images is proposed to classify five sky conditions （stratus, cumulus, altocumulus, cirrus and clear sky） automatically based on cloud images obtained from the whole sky infrared cloud meas- uring system （WSICMS）. The WSICMS is a ground-based passive sensor that uses an uncooled microbolometer detector array to measure downwelling atmospheric radiance in the 8--14 μm wavelength band of the electromagnetic spec- trum. It provides a way to identify clouds, obtain clouds distributions and calculate clouds amounts contin- uously with no difference in sensitivity during day and night. The primary WSICMS components are opti- cal detector, environmental parameter sensors, controller and power component. The optical detector is an uncooled microbometer array containing 320 × 240 pixels. It obtains nine images at zenith and at each eight orientations under the control of the scan servo system. A whole sky image is accomplished after spelling nine images, water vapor correction and zenith angles correction. The WSICMS locating at Nanjing, China has been working since August 2006. The 200 cloud images according to human observations are selected randomly from these sample sets. Before cloud classification, an appropriate FUTS filter window （7× 7） is chosen. Analyses of FUTS of five different sky conditions and same sky co

关 键 词：云分类 模糊纹理光谱 全天空红外测云系统 

分 类 号：P426.5[天文地球—大气科学及气象学]