کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9619542 158444 2005 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Automatic thresholding for hemispherical canopy-photographs based on edge detection
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علم هواشناسی
پیش نمایش صفحه اول مقاله
Automatic thresholding for hemispherical canopy-photographs based on edge detection
چکیده انگلیسی
The analysis of hemispherical photographs is nowadays an established method for assessing light indirectly and describing canopy structures. In this article, we present an automatic threshold algorithm for separating canopy and sky by edge detection. The algorithm was evaluated under different canopy conditions by comparing its results for canopy openness, fractal dimension and diffuse transmittance with those from multiple manual thresholding and direct measurements of the percent photosynthetic photon flux density (PPFD). We show that the automatic threshold algorithm is appropriate to replace the widely used manual interactive processing. It also improves the accuracy of results, especially in comparison with single manual thresholding. Whereas manual threshold setting has often been criticised as subjective and a major source of error the less time-consuming edge detection approach is objective, reproducible and can be applied to a large number of images.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Agricultural and Forest Meteorology - Volume 128, Issues 3–4, 28 February 2005, Pages 243-250
نویسندگان
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