coiR - Analysis of Canopy Openness Index from Fisheye Images

Tools to estimate the Canopy Openness Index (COI) from hemispherical (fisheye) canopy photographs. The package imports canopy images, crops them to the circular area delimited by the fisheye lens, binarizes them to separate sky from vegetation pixels, and computes the index as the proportion of sky pixels in the cropped image. Canopy openness is a measure related to canopy closure, canopy cover and understorey illumination, as discussed in Jennings, Brown and Sheil (1999) "Assessing forest canopies and understorey illumination: canopy closure, canopy cover and other measures" <doi:10.1093/forestry/72.1.59>. Example canopy images are included so users can test the workflow.