9.3. Distance Map

9.3.1. Overview

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. Activating the filter

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

9.3.3. Options

Figura 17.167. «Distance Map» options

«Distance Map» options

Presets, Preview, Split view
[Nota] Nota

These options are described in Secció 2, «Característiques comunes».

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

Figura 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.

Figura 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...