zenith_image: Build Zenith image

In rcaiman: CAnopy IMage ANalysis

Build Zenith image

Description

Build a single-layer image with zenith angle values, assuming upwards-looking hemispherical photography with the optical axis vertically aligned.

Usage

zenith_image(diameter, lens_coef)

Arguments

diameter	numeric vector of length one. Diameter in pixels expressed as an even integer. This places the zenith point between pixels. Snapping the zenith point between pixels does not affect accuracy because half-pixel is less than the uncertainty in localizing the circle within the picture.
lens_coef	numeric vector. Polynomial coefficients of the lens projection function. See lens().

Value

terra::SpatRaster with zenith angles in degrees, showing a complete hemispherical view with the zenith at the center. The object carries attributes lens_coef.

Examples

z <- zenith_image(600, lens("Nikon_FCE9"))
plot(z)

rcaiman documentation built on Sept. 9, 2025, 5:42 p.m.