9.3. Distance Map

9.3.1. Généralités

Each pixel in the image is replaced with a gray value dependent on the distance to the nearest obstacle pixel, generally a boundary pixel. Different methods can be used to calculate the distance.

9.3.2. Ouverture du filtre

This filter is found in the image window menu under FiltersGenericDistance Map….

9.3.3. Options

Figure 17.167. « Distance Map » options

Distance Map options

Presets, Preview, Split view
[Note] Note

These options are described in Section 2, « Options communes ».

Metric

« Metric » is a topology term. Three methods are available:

  • Euclidean default: the distance is a line.

  • Manhattan

  • Chebyshev

Threshold low

Default is 0. Increasing this value selects higher lightness pixels

Original image for examples. Threshold low will be progressively increased. Lightness: dark red = 0.070; bright red = 0.223; green = 0.133

Figure 17.168. « Threshold low » example

Threshold low example

Threshold low = 0: only border distances are visible.

Threshold low example

Threshold low = 0.070: « dark red » circle appears.

Threshold low example

Threshold low = 0.133: « green » circle appears.

Threshold low example

Threshold low = 0.223: « bright red » circle appears.


Threshold high

Default is 100. Decreasing this value makes result lighter.

Grayscale Averaging

Number of computations for grayscale averaging.

Normalize

This option is checked by default. If you uncheck it, no blur is created.

Figure 17.169. « Normalize » example

Normalize example

Normalize option checked.

Normalize example

Normalize option unchecked.


9.3.4. Using Distance Map filter

Searching for an example using Distance map filter in image processing...