| binarize_fisheye | Compute the threshold of a single-channel fisheye image, and return a binary fisheye image of canopy (0) and gap (1) pixels | 
| camera_fisheye | Provide circular mask parameters from known camera+fisheye lens models | 
| canopy_fisheye | Calculate canopy attributes from angular gap fraction data derived from fisheye images | 
| gapfrac_fisheye | Derive angular gap fraction from a classified fisheye image | 
| import_fisheye | Import a fisheye image as a single channel raster, and apply a circular mask | 
| list.cameras | Import a fisheye image as a single channel raster, and apply a circular mask | 
| list.lenses | Derive angular gap fraction from a classified fisheye image | 
| zonal_mask | Divide a raster image into four stacks which are used as masks. |