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Chinese Journal of Applied Ecology ›› 2018, Vol. 29 ›› Issue (10): 3183-3190.doi: 10.13287/j.1001-9332.201810.012

• Research paper • Previous Articles     Next Articles

Measuring the dynamics of leaf area index of vegetation using fisheye camera

NIU Xiao-tao1,2, FAN Jun1,3*, WANG Sheng1,2, WANG Qiu-ming3   

  1. 1State Key Laboratory of Soil Erosion and Dry land Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling 712100, Shaanxi, China;
    2University of Chinese Academy of Sciences, Beijing 100049, China;
    3College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China
  • Received:2018-01-29 Online:2018-10-20 Published:2018-10-20
  • Supported by:
    This work was supported by the Western Young Scholars Project (Class A) of Chinese Academy of Sciences (XAB2015A03) and the National Natural Science Foundation of China (41571224).

Abstract: The rapid and accurate measurement of LAI is of great importance for the research of ecological processes. Photos from typical land use types in the northern Loess Plateau, including Caragana, Salix, alfalfa, wild grass, soybean and maize, were measured by digital hemispherical photography (DHP). Meanwhile, photos were daily taken by video camera with fisheye lens and the pictures were analyzed by image processing software to obtain the dynamics of LAI in soybean, maize and Caragana fields. The results showed that a linear correlation existed between the LAI measured by DHP and LAI-2200. The coefficient of determination (R2) was 0.85 (P<0.05) and root mean square error (RMSE) was 0.256. The key parameters of professional software were affected by the local solar radiation. When the downward lens was used, the green index was the key parameter which increased with the increase of solar radiation. However, the brightness index decreased with the increase of solar radiation when the lens was upward. Through the adjustment of the key parameters, the results of LAI of maize, soybean, and Caragana were consistent with the LAI-2200 results, well reflecting LAI dynamics during the plant growth. The downward lens in Caragana field was better. The fisheye camera could be used for monitoring the dynamic LAI of different vegetations.