rcaiman (version 2.0.1)

fisheye_to_pano: Fisheye to panoramic

Description

Reprojects a fisheye (hemispherical) image into a panoramic view using a cylindrical projection. The output is standardized so that rows correspond to zenith angle bands and columns to azimuthal sectors.

Usage

fisheye_to_pano(r, z, a, fun = mean, angle_width = 1)

Value

terra::SpatRaster with rows representing zenith angle bands and columns representing azimuthal sectors. The number of layers and names matches that of the input r.

Arguments

r

terra::SpatRaster of one or more layers (e.g., RGB channels or binary masks) in fisheye projection.

z

terra::SpatRaster generated with zenith_image().

a

terra::SpatRaster generated with azimuth_image().

fun

function taking a numeric/logical vector and returning a single numeric or logical value (default mean).

angle_width

numeric vector of length one. Angle in deg that must divide both 0–360 and 0–90 into an integer number of segments. Retrieve a set of valid values by running lapply(c(45, 30, 18, 10), function(a) vapply(0:6, function(x) a/2^x, 1)).

Details

This function computes a cylindrical projection by aggregating pixel values according to their zenith and azimuth angles. Internally, it creates a segmentation grid with sky_grid_segmentation() and applies extract_feature() to compute a summary statistic (e.g., mean) of pixel values within each cell.

References

Examples

if (FALSE) {
caim <- read_caim()
z <- zenith_image(ncol(caim), lens())
a <- azimuth_image(z)
pano <- fisheye_to_pano(caim, z, a)
plotRGB(pano %>% normalize_minmax() %>% multiply_by(255))
}