The SPHORB (Spherical ORB) package is an implementation in OpenCV of the algorithm introduced in "SPHORB: A Fast and Robust Binary Feature on the Sphere" by Zhao et al. This algorithm is designed to detect and describe the features for spherical panoramic images, which are more and more easily obtained for common users. Based on a nearly regular hexagonal grid parametrization of the sphere - geodesic grid, we can adopt the planar ORB features to the spherical domain and achieve satisfactory performance.

SPHORB is distributed under the GNU General Public License. For information on commercial licensing, please contact the authors at the contact address below.

If you use this package in published work, please cite our work as

@article{zhao-SPHORB,
    author   = {Qiang Zhao and Wei Feng and Liang Wan and Jiawan Zhang},
    title    = {SPHORB: A Fast and Robust Binary Feature on the Sphere},
    journal  = {International Journal of Computer Vision},
    doi      = {10.1007/s11263-014-0787-4},
    year     = {2015},
    volume   = {113},
    number   = {2},
    pages    = {143-159},
}

Before using SPHORB, you need to install the OpenCV library. OpenCV 2.4.2 is used in our implementation.

In the repository, there are some folders and files.

-- Data folder
                the data used to accelerate or simplify the algorithm

-- Image folder
                the first image pair is for camera rotation with the source image from SUN360 database[1], 
        the second pair is for camera movement with the two images from Google Street View (C).

-- pfm.h pfm.cpp
                reader for PFM(Portable Float Map) file

-- utility.h utility.cpp
                the utility functions for ratio matching strategy and drawing matches
        (different with the "drawMatches" function of OpenCV)

-- detector.h detector.cpp nonmax.cpp
                spherical FAST detector trained using the scheme of Rosten and Drummond[2], 
        and the non-maximal suppression using FAST score

-- SPHORB.h SPHORB.cpp
                the SPHORB algorithm

-- example1.cpp example2.cpp
                two test cases

[1] J. Xiao, K. Ehinger, A. Oliva, and A. Torralba. Recognizing scene viewpoint using panoramic place representation. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 2695¨C2702, 2012.

[2] E. Rosten and T. Drummond. Machine learning for highspeed corner detection. In Proceedings of the European Conference on Computer Vision (ECCV), 2006.

$ mkdir build
$ cd build
$ cmake ..
$ make

Run Example (from root directory)
Example 1: $ ./build/example1 Image/1_1.jpg Image/1_2.jpg
Example 2: $ ./build/example2 Image/2_1.jpg Image/2_2.jpg

For any questions, comments, bug reports or suggestions, please send email to Qiang Zhao at [email protected].