Rotational Invariant Object Recognition for Robotic Vision

Depth cameras have enhanced the environment perception for robotic applications significantly. They allow to measure true distances and thus enable a 3D measurement of the robot surroundings. In order to enable robust robot vision, the objects recognition has to handle rotated data because object can be viewed from different dynamic perspectives when the robot is moving. Therefore, the 3D descriptors used of object recognition for robotic applications have to be rotation invariant and implementable on the embedded system, with limited memory and computing resources. With the popularization of the depth cameras, the Histogram of Gradients (HOG) descriptor has been extended to recognize also 3D volumetric objects (3DVHOG). Unfortunately, both version are not rotation invariant. There are different methods to achieve rotation invariance for 3DVHOG, but they increase significantly the computational cost of the overall data processing. Hence, they are unfeasible to be implemented in a low cost processor for real-time operation. In this paper, we propose an object pose normalization method to achieve 3DVHOG rotation invariance while reducing the number of processing operations as much as possible. Our method is based on Principal Component Analysis (PCA) normalization. We tested our method using the Princeton Modelnet10 dataset.