distmap {EBImage} | R Documentation

## Distance map transform

### Description

Computes the distance map transform of a binary image. The distance map is a matrix which contains for each pixel the distance to its nearest background pixel.

### Usage

    distmap(x, metric=c('euclidean', 'manhattan'))

### Arguments

`x` | An `Image` object or an array. `x` is considered as a binary image, whose pixels of value 0 are considered as background ones and other pixels as foreground ones.
`metric` | A character indicating which metric to use, L1 distance (`manhattan`) or L2 distance (`euclidean`). Default is `euclidean`.

### Details

A fast algorithm of complexity O(M*N*log(max(M,N))), where (M,N) are the dimensions of `x`, is used to compute the distance map.

### Value

An `Image` object or an array, with pixels containing the distances to the nearest background points.

### Author(s)

Gregoire Pau, gpau@ebi.ac.uk, 2008

### References

M. N. Kolountzakis, K. N. Kutulakos. Fast Computation of the Euclidean Distance Map for Binary Images, Infor. Proc. Letters 43 (1992).

### Examples

      x = readImage(system.file("images", "shapes.png", package="EBImage"))
      display(x)
      dx = distmap(x)
      display(dx/10, title='Distance map of x')

[Package EBImage version 4.20.1 Index]