spatstat (version 1.48-0)

Math.im: S3 Group Generic methods for images

Description

These are group generic methods for images of class "im", which allows for usual mathematical functions and operators to be applied directly to images. See Details for a list of implemented functions.

Usage

## S3 methods for group generics have prototypes:
Math(x, ...)
Ops(e1, e2)
Complex(z)
Summary(..., na.rm = FALSE)

Arguments

x, z, e1, e2

objects of class "im".

...

further arguments passed to methods.

na.rm

logical: should missing values be removed?

Details

Below is a list of mathematical functions and operators which are defined for images. Not all functions will make sense for all types of images. For example, none of the functions in the "Math" group make sense for character-valued images. Note that the "Ops" group methods are implemented using eval.im, which tries to harmonise images via harmonise.im if they aren't compatible to begin with.

1. Group "Math":
   • abs, sign, sqrt, floor, ceiling, trunc, round, signif

exp, log, expm1, log1p, cos, sin, tan, cospi, sinpi, tanpi, acos, asin, atan

cosh, sinh, tanh, acosh, asinh, atanh

lgamma, gamma, digamma, trigamma

cumsum, cumprod, cummax, cummin

Group "Ops":

• "+", "-", "*", "/", "^", "%%", "%/%"

"&", "|", "!"

"==", "!=", "<"< code="">, "<="< code="">, ">=", ">"

Group "Summary":

• all, any
• sum, prod
• min, max
• range

Group "Complex":

• Arg, Conj, Im, Mod, Re

See Also

eval.im for evaluating expressions involving images.

Examples

  ## Convert gradient values to angle of inclination:
  V <- atan(bei.extra$grad) * 180/pi
  ## Make logical image which is TRUE when heat equals 'Moderate': 
  A <- (gorillas.extra$heat == "Moderate")
  ## Summary:
  any(A)
  ## Complex:
  Z <- exp(1 + V * 1i)
  Z
  Re(Z)