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

图 17.167. Distance Map options

Distance Map options

Presets, Preview, Split view
[注意] 注意

These options are described in 第 2 节 “Common Features”.

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

图 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.

图 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...