3D-Object Recognition Based on LLC Using Depth Spatial Pyramid

Recently introduced high-accuracy RGB-D cameras are capable of providing high quality three-dimension information (color and depth information) easily. The overall shape of the object can be understood by acquiring depth information. However, conventional methods adopted this camera use depth information only to extract the local feature. To improve the object recognition accuracy, in our approach, the overall object shape is expressed by the depth spatial pyramid based on depth information. In more detail, multiple features within each sub-region of the depth spatial pyramid are pooled. As a result, the feature representation including the depth topological information is constructed. We use histogram of oriented normal vectors (HONV) designed to capture local geometric characteristics as 3D local features and locality-constrained linear coding (LLC) to project each descriptor into its local-coordinate system. As a result of image recognition, the proposed method has improved the recognition rate compared with conventional methods.