makeRimage: Generate a RelativeRadiusImage.

In GastonMauroDiaz/caiman: Canopy Image Analysis

Description

Helper function to generate a RelativeRadiusImage. Compute relative radius for each pixes needed to represent a circular hemispherical image with a 180 degrees field of view and a given diameter, expressed in pixels. For definition of relative radius see details of lensPolyCoef.

Usage

makeRimage(x, y)

## S4 method for signature 'numeric,missing'
makeRimage(x)

## S4 method for signature 'numeric,LensPolyCoef'
makeRimage(x, y)

Arguments

x	numeric. Diameter of the circle in pixels expressed as one-length even integer.
y	LensPolyCoef.

Details

Most digital cameras take photos with an aspect ratio of 3:4, which means a rectangular frame. If all the circle area is in the picture frame, hundreds of pixels will have no-data. RelativeRadiusImage has 1:1 aspect ratio to minimize no-data pixels, so the circle is inscribed in a square. The size of the square equals the diameter of the circle. To represent the zenith as a point between pixels, the diameter of the circle must be even. In a high resolution image this restriction of snapping the zenith between pixels does not affect accuracy because half-pixel is less than the uncertainty in localizing the circle in the frame.

Value

RelativeRadiusImage.

Methods (by class)

• x = numeric,y = missing: Assuming a polar projection.

• x = numeric,y = LensPolyCoef: Used to specified a projection different from the polar.

See Also

makeZimage.

Examples

x <- makeRimage(480)
plot(x)
x

GastonMauroDiaz/caiman documentation built on Jan. 22, 2022, 4:43 a.m.