A distance transform, also known as distance map or distance field, is a derived representation of a digital image. The choice of the term depends on the point of view on the object in question: whether the initial image is transformed into another representation, or it is simply endowed with an additional map or field.
The map labels each pixel of the image with the distance to the nearest obstacle pixel. A most common type of obstacle pixel is a boundary pixel in a binary image. See the image for an example of a chessboard distance transform on a binary image.
- Euclidean distance
- Taxicab geometry, also known as City block distance or Manhattan distance.
- Chessboard distance
- Fast distance transform in C++ by Felzenszwalb and Huttenlocher
- Distance Transform tutorials in CVonline
- Survey of fast exact Euclidean distance transform algorithms
- Lecture notes on Euclidean distance transform
- Using distance mapping for AI
- Distance Transforms by Henry Kwong and Dynamic Step Distance Transforms by Richard Scott, The Wolfram Demonstrations Project.
- Morphological DistanceTransform function in Mathematica
- Morphological InverseDistanceTransform function in Mathematica