Robust local binary descriptor in rotation change using polar location

Rotation change is widespread in many computer vision applications. Robustness in the rotation is an important capability in evaluating local descriptors. We proposed a fast and rotation-robust local binary descriptor using polar location, called rotation-robust local difference binary descriptor (RLDB). The code of RLDB is generated by a binary test of average intensity, radial gradient, and tangent gradient of grid cells on multiple log-polar grids, which will save the presented local descriptors from spending extra time dealing with rotation changes. To speed up the computation, two tricks are proposed in the construction of the descriptor: one is using a lookup table mapping discrete polar coordinates with image pixel locations; the other is rebuilding the integral image in polar coordinates. Experimental results demonstrate that the presented descriptor is shown to be more robust in large rotation changes and viewpoint changes than some state-of-the-art local descriptors. At the same time, they also have comparable distinctive performance and construction speed.