RORPO : Ranking the Orientation Responses of Path Operators

The analysis of thin curvilinear objects in 3D images is a complex and challenging task.
We introduced a new, non-linear operator, called RORPO (Ranking the Orientation Responses of Path Operators)  built upon the notion of path operator from mathematical morphology.
This operator, unlike most operators commonly used for 3D curvilinear structure analysis, is discrete, non-linear and non-local.
From this new operator, two main curvilinear structure characteristics can be estimated:

  • An intensity feature, that can be assimilated to a quantitative measure of curvilinearity
  • A directional feature, providing a quantitative measure of the structure’s orientation.
Illustration of RORPO in 2D

Initial image


RORPO intensity feature


RORPO directional feature

To see more:

  • PhD thesis
  • Code (C++):
    • 2D version available on IPOL (online demo + sources)
    • 3D version only for the intensity feature on github