DOI: 10.1016/j.atmosenv.2017.12.005
Scopus记录号: 2-s2.0-85037994052
论文题名: Use of cameras for monitoring visibility impairment
作者: Malm W ; , Cismoski S ; , Prenni A ; , Peters M
刊名: Atmospheric Environment
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2018
卷: 175 起始页码: 167
结束页码: 183
语种: 英语
英文关键词: Extinction
; Image indexes
; Visibility
; Webcams
Scopus关键词: Cameras
; Color photography
; Image resolution
; Light extinction
; Lighting
; Visibility
; Atmospheric conditions
; Atmospheric extinction
; Image indexes
; Lighting conditions
; Temporal averaging
; Visibility conditions
; Visibility impairment
; WebCams
; Image enhancement
; cloud cover
; extinction
; federal system
; haze
; image resolution
; national park
; policy making
; visibility
; Article
; cloud
; environmental monitoring
; haze
; illumination
; priority journal
; quantitative analysis
; technology
; visibility
; weather
Scopus学科分类: Environmental Science: Water Science and Technology
; Earth and Planetary Sciences: Earth-Surface Processes
; Environmental Science: Environmental Chemistry
英文摘要: Webcams and automated, color photography cameras have been routinely operated in many U.S. national parks and other federal lands as far back as 1988, with a general goal of meeting interpretive needs within the public lands system and communicating effects of haze on scenic vistas to the general public, policy makers, and scientists. Additionally, it would be desirable to extract quantifiable information from these images to document how visibility conditions change over time and space and to further reflect the effects of haze on a scene, in the form of atmospheric extinction, independent of changing lighting conditions due to time of day, year, or cloud cover. Many studies have demonstrated a link between image indexes and visual range or extinction in urban settings where visibility is significantly degraded and where scenes tend to be gray and devoid of color. In relatively clean, clear atmospheric conditions, clouds and lighting conditions can sometimes affect the image radiance field as much or more than the effects of haze. In addition, over the course of many years, cameras have been replaced many times as technology improved or older systems wore out, and therefore camera image pixel density has changed dramatically. It is shown that gradient operators are very sensitive to image resolution while contrast indexes are not. Furthermore, temporal averaging and time of day restrictions allow for developing quantitative relationships between atmospheric extinction and contrast-type indexes even when image resolution has varied over time. Temporal averaging effectively removes the variability of visibility indexes associated with changing cloud cover and weather conditions, and changes in lighting conditions resulting from sun angle effects are best compensated for by restricting averaging to only certain times of the day. © 2017 Elsevier Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/83089
Appears in Collections: 气候变化事实与影响
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作者单位: Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, CO, United States; Air Resource Specialists, Inc., Fort Collins, CO, United States; National Park Service, Air Resources Division, Lakewood, CO, United States
Recommended Citation:
Malm W,, Cismoski S,, Prenni A,et al. Use of cameras for monitoring visibility impairment[J]. Atmospheric Environment,2018-01-01,175