Thin objects in 3D volumes, for instance vascular networks in medical imaging or various kinds of fibres in materials science, have been of interest for some time to computer vision. Particularly, tubular objects are everywhere elongated in one principal direction – which varies spatially – and are thin in the other two perpendicular directions. Filters for detecting such structures use for instance an analysis of the three principal directions of the Hessian, which is a local feature. RORPO is a low-level tubular structure detection filter. This filter relies on paths, which are semi-global features that avoid any blurring effect induced by scale-space convolution. More precisely, our filter is based on recently developed morphological path operators.
We provide the libRORPO library containing:
- A function computing the Path Opening with one orientation (PO_3D)
- A function computing the Robust Path Opening in all orientations (Get_RPO_Orientations)
- A function computing the Ranking Orientations Responses of Path Operators (RORPO)
- A function computing the multiscale Ranking Orientations Responses of Path Operators (RORPO_multiscale)
In the RORPO_multiscale_Usage directory, you can find the full RORPO_multiscale function used in the ECCV paper.
- Compile the libRORPO
- Compile the function with the CMakeLists in the RORPO_multiscale_Usage directory. You need to change the path of FIND_LIBRARY to the one where you compiled libRORPO and include_directories to the one where the header libRORPO are.
- VTK version 6 or greater is needed
- Niftilib (provided) is needed
- Accepted type : int8, uint8, int16, uint16, int32, uint32, float
- An isotropic image resolution is required (cubic voxels).
: path to .nii image (string). : path to write the resulting image (string). : Minimum path length (int) : factor for the geometric sequence of scales; scale_(n+1) = factor * scale_(n) (float) : Number of scales (int) Options: --window: Intensity range from the input image (2 int: window_min, window_max) Convert input image to uint8. Intensities inferior to window_min become 0, intensities superior to window_max become 255; Linear transformation between window_min and window_max --core: Number of CPUs used for RPO computation (int) --mask or : Path to a mask image (0 for the background and 1 for the foreground). RORPO will only be computed in this mask. The mask image type must be uint8. --verbose: Activation of a verbose mode. Usage Example : ./RORPO_multiscale_usage input.nii output.nii 40 1.32 4 Usage Example : ./RORPO_multiscale_usage input.nii output.nii 40 1.32 4 --window 0,255 --verbose --core 4
The synthetic image of the article (
plan_spiral_blob_short_5_5_0.9.nii) is also
provided to quickly test the filtering. Moreover, we provide the RORPO filtering result using the same set of parameters as in the article.
Odyssée Merveille (@odyssee-merveille), Hugues Talbot (@hugues-talbot), Laurent Najman (@lnajman), and Nicolas Passat.
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