Welcome to libRORPO, a mathematical morphology library for Path Operators. RORPO is a morphological vesselness operator, meant to detect vessels and other tubular structures in medical images.

This library comes with the following optional bindings :

• A python interface using pybind11.
• A 3DSlicer interface to use RORPO in the interactive 3D environment of Slicer.

WARNING : All images are expected to have an isotropic image resolution (cubic voxels). The software will produce a result if this not the case but the interpretation of this result will be questionable.

PO_3D: Compute the Path Opening operator in one orientation. The 7 orientations are defined in the function RPO.

template<typename T, typename MaskType>
void PO_3D(const Image3D<T> &image, int L, std::vector<IndexType> &index_image, std::vector<int> &orientations, Image3D<T> &Output, std::vector<bool> b)

• image : Input image
• L : Path length
• index_image : sorted index of the image. Result of the sort_image_value function of sorting.hpp
• orientations : defined the orientation used. Choices are [0,0,1] ; [1,0,0] ; [0,1,0] ; [1,1,1] ; [-1,1,1] ; [1,1,-1] ; [-1,1,-1]
• Output : Result of the Path Opening

RPO : Compute the 7 orientations of the Robust Path Opening and return them.

template<typename T, typename MaskType>
std::array<std::vector<int>, 7> RPO(const Image3D<T> &image, int L, Image3D<T> &RPO1, Image3D<T> &RPO2, Image3D<T> &RPO3, Image3D<T> &RPO4,
                                    Image3D<T> &RPO5, Image3D<T> &RPO6, Image3D<T> &RPO7, int nb_core, int dilationSize, Image3D<MaskType> &Mask) {

• image : input image
• L : Path length
• RPO1 : resulting Robust Path Opening in the first orientation.
• RPO2 : resulting Robust Path Opening in the second orientation
• RPO3 : resulting Robust Path Opening in the third orientation
• RPO4 : resulting Robust Path Opening in the fourth orientation
• RPO5 : resulting Robust Path Opening in the fifth orientation
• RPO6 : resulting Robust Path Opening in the sixth orientation
• RPO7 : resulting Robust Path Opening in the seventh orientation
• nb_core : number of cores used to compute the Path Opening (choose between 1 and 7)

RORPO: Compute the Ranking Orientations Responses of Path Operators

template<typename T, typename MaskType>
Image3D<T> RORPO(const Image3D<T> &image, int L, int nbCores, int dilationSize, Image3D<MaskType> &mask) {

• image: input image
• L: Path length
• nb_core: number of cores used to compute the Path Opening (choose between 1 and 7)
• dilationSize: Size of the dilation for the noise robustness step.
• mask: optional mask image

RORPO_multiscale: Compute the multiscale RORPO

template<typename PixelType, typename MaskType>
Image3D<PixelType> RORPO_multiscale(const Image3D<PixelType> &I, const std::vector<int>& S_list, int nb_core, int dilationSize, int debug_flag, Image3D<MaskType> &Mask)

• I: input image
• S_list : vector containing the different path length (scales)
• nb_core : number of cores used to compute the Path Opening (choose between 1 and 7)
• debug_flag : 1 (activated) or 0 (desactivated)
• Mask : optional mask image