The Angular Block OTSU for Canopy Porosity of Hemisphere Method

The leaf area index reflects the growth of vegetation. The hemispheric image method is a common method for measuring the leaf area index. However, fisheye lenses, containing a large number of mixed cells, would change the luminosity of images. Traditional threshold methods will increase the error in calculating the key variable of the leaf area index, the canopy porosity. So, they cannot distinguish the sky and the leaves efficiently. This paper proposes the Angular Block Otsu algorithm, an improved algorithm based on Otsu for canopy fisheye images. Compared with previous methods, it can retain or highlight the original detail information of the image better, so that the accuracy of the canopy porosity calculation is greatly improved.