Sequential region labelling, also known as connected components is a standard image segmentation problem that joins contiguous foreground pixels into blobs. Despite its long development history and widespread use across diverse domains such bone biology, materials science geology, labelling can still form bottleneck in processing pipelines. Here, I describe multithreaded implementation of class...

We present faster algorithms for computing the 2-edge and 2-vertex strongly connected components of a directed graph, which are straightforward generalizations of strongly connected components. While in undirected graphs the 2-edge and 2-vertex connected components can be found in linear time, in directed graphs only rather simple O(mn)-time algorithms were known. We use a hierarchical sparsifi...

Article history: Received 8 August 2008 Received in revised form 21 January 2012 Accepted 8 March 2014 Available online 19 March 2014

Labeling of connected components in an image or a raster of non-imagery data is a fundamental operation in fields of pattern recognition and machine intelligence. The bulk of effort devoted to designing efficient connected components labeling (CCL) algorithms concentrated on the domain of binary images where labeling is required for a computer to recognize objects. In contrast, in the Geographi...

We consider high-order connectivity in k-uniform hypergraphs defined as follows: Two j-sets are j-connected if there is a walk of edges between them such that two consecutive edges intersect in at least j vertices. We describe the evolution of jconnected components in the k-uniform binomial random hypergraph H(n, p). In particular, we determine the asymptotic size of the giant component shortly...

Improved parallel, external and parallel-external algorithms for list-ranking and computing the connected components of a graph are presented. These algorithms are implemented and tested on a cluster of workstations using the C programming language and mpich, a portable implementation of the MPI (Message-Passing Interface) standard.