Pruning (morphology)
Encyclopedia
The pruning algorithm is a technique used in digital image processing
based on mathematical morphology
. It is used as a complement to the skeleton
and thinning algorithms to remove unwanted parasitic components. In this case 'parasitic' components refer to branches of a line which are not key to the overall shape of the line and should be removed. These components can often be created by edge detection
algorithms or digitisation
.
The standard pruning algorithm will remove all branches shorter than a given number of points. The algorithm starts at the end points and recursively removes a given number (n) of points from each branch. After this step it will apply dilatation on the new end points with a (2N+1)(2N+1) structuring element of 1’s and will intersect the result with the original image. If a parasitic branch is shorter than four points and we run the algorithm with n = 4 the branch will be removed. The second step ensures that the main trunks of each line are not shortened by the procedure.
Digital image processing
Digital image processing is the use of computer algorithms to perform image processing on digital images. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing...
based on mathematical morphology
Mathematical morphology
Mathematical morphology is a theory and technique for the analysis and processing of geometrical structures, based on set theory, lattice theory, topology, and random functions...
. It is used as a complement to the skeleton
Topological skeleton
In shape analysis, skeleton of a shape is a thin version of that shape that is equidistant to its boundaries. The skeleton usually emphasizes geometrical and topological properties of the shape, such as its connectivity, topology, length, direction, and width...
and thinning algorithms to remove unwanted parasitic components. In this case 'parasitic' components refer to branches of a line which are not key to the overall shape of the line and should be removed. These components can often be created by edge detection
Edge detection
Edge detection is a fundamental tool in image processing and computer vision, particularly in the areas of feature detection and feature extraction, which aim at identifying points in a digital image at which the image brightness changes sharply or, more formally, has discontinuities...
algorithms or digitisation
Digitizing
Digitizing or digitization is the representation of an object, image, sound, document or a signal by a discrete set of its points or samples. The result is called digital representation or, more specifically, a digital image, for the object, and digital form, for the signal...
.
The standard pruning algorithm will remove all branches shorter than a given number of points. The algorithm starts at the end points and recursively removes a given number (n) of points from each branch. After this step it will apply dilatation on the new end points with a (2N+1)(2N+1) structuring element of 1’s and will intersect the result with the original image. If a parasitic branch is shorter than four points and we run the algorithm with n = 4 the branch will be removed. The second step ensures that the main trunks of each line are not shortened by the procedure.
External Links
- Morphological Pruning function in MathematicaMathematicaMathematica is a computational software program used in scientific, engineering, and mathematical fields and other areas of technical computing...