Abstract: Canopy gap fraction is one of the important parameters of leaf area index calculation,playing a crucial role in evaluating canopy growth.In this paper,MATLAB is applied to analyze hemispherical photographs to obtain reasonable values of canopy gap fraction.After extracting the single color component,the photographs are segmented to get effective area,then information of every pixel is extracted and calculated to get values of canopy gap fraction through using improved OTSU algorithms.By contrasting values of canopy gap fraction with processing results of Winscanopy,it can draw a conclusion that correlation of both sides is very high.The proposed calculation method opens up new avenues for effectively getting canopy gap fraction.

Key words: Matlab, hemispherical photographs, canopy gap graction, image processing