imager: distance_transform – R documentation

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distance_transform

Compute Euclidean distance function to a specified value.

Description

The distance transform implementation has been submitted by A. Meijster, and implements the article 'W.H. Hesselink, A. Meijster, J.B.T.M. Roerdink, "A general algorithm for computing distance transforms in linear time.", In: Mathematical Morphology and its Applications to Image and Signal Processing, J. Goutsias, L. Vincent, and D.S. Bloomberg (eds.), Kluwer, 2000, pp. 331-340.' The submitted code has then been modified to fit CImg coding style and constraints.

Usage

distance_transform(im, value, metric = 2L)

Arguments

`im`	an image
`value`	Reference value.
`metric`	Type of metric. Can be <tt> 0=Chebyshev \| 1=Manhattan \| 2=Euclidean \| 3=Squared-euclidean </tt>.

Examples

imd <- function(x,y) imdirac(c(100,100,1,1),x,y)
#Image is three white dots
im <- imd(20,20)+imd(40,40)+imd(80,80)
plot(im)
#How far are we from the nearest white dot? 
distance_transform(im,1) %>% plot

imager

Image Processing Library Based on 'CImg'

v0.42.10

LGPL-3

Authors

Simon Barthelme [aut], David Tschumperle [ctb], Jan Wijffels [ctb], Haz Edine Assemlal [ctb], Shota Ochi [cre]

Initial release