Open AccessCloud Determination of All-Sky Images under Low-Visibility Conditions
Author(s) -
Juan Huo,
Daren Lü
Publication year - 2009
Publication title -
journal of atmospheric and oceanic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.774
H-Index - 124
eISSN - 1520-0426
pISSN - 0739-0572
DOI - 10.1175/2009jtecha1324.1
Subject(s) - visibility , sky , cloud computing , computer science , remote sensing , key (lock) , environmental science , computer vision , artificial intelligence , meteorology , geology , physics , computer security , operating system
The threshold method is commonly used to determine cloud in a sky image. This paper evaluates the method by numerical simulation and shows that the aerosol optical depth (AOD) is a key factor that influences the accuracy. Particularly when the visibility is low, a single threshold method is inappropriate. To improve the accuracy of cloud determination from low-visibility sky images, an integrated cloud-determination algorithm is presented that is based on the fast Fourier transform, symmetrical image features, and threshold methods. The preliminary comparison tests show that the new integrated method improves the ability to determine cloud under lower-visibility conditions.