Self-supervised category-level 6D pose estimation stands as a fundamental task in computer vision. However, current self-supervised methods face two major challenges. Firstly, existing networks struggle to reconstruct precise object models due to significant part-level shape variations among specific categories. Secondly, they are impacted by the many-to-one ambiguity in the correspondences between pixels and point clouds. To address these challenges, we propose a novel approach that includes a Part-level Shape Reconstruction (PSR) module and a Coarse-to-Fine Correspondence Optimization (CFCO) module. In the (PSR) module, we introduce a part-level discrete shape memory to capture more fine-grained shape variations of different objects and use it to perform precise reconstruction. In the (CFCO) module, we utilize Hungarian matching to generate one-to-one pseudo labels at both region and pixel levels, which provides explicit supervision for the corresponding similarity matrices. We evaluate our method on the REAL275 and WILD6D datasets. Our extensive experiments show that our self-supervised approach outperforms existing methods and achieves new state-of-the-art results within the self-supervised framework.

As a more energy-efficient WPT technology, directional WPT is applied to supply energy for wireless rechargeable sensor networks (WRSNs). Conventional methods that ignore anisotropic energy receiving property of rechargeable sensors cause a waste of energy. To address this issue, in this paper, we focus on minimizing the charging delay with a directional charging scheme. At first, we introduce linear constraints to improve an energy transfer model, which is verified to be practical by experiments. Then, we concern a Minimal chArging Delay with Single charger (S-MAD) problem to promote efficiency, followed by an Optimal Direction Charge with Single charger (S-ODC) solution. Through discretizing charging power and angle, we bound the performance gap of the solution to the optimal one with$\text{a}^{^{^{^{}}}}\,\,\frac {1}{1-\epsilon ^{2}}$approximation ratio, where$\epsilon $is the error threshold of discretization. After that, we extend the original S-MAD problem into the large scale WRSN with multiple chargers (i.e., M-MAD) and solve it by proposing M-ODC (i.e., Optimal Direction Charge with Multiple chargers (M-ODC)). Theoretical analyses are presented to exploit the feature of the proposed schemes. Finally, we demonstrate that our methods outperform the baseline methods by an average of 34.2% through simulations and test-bed experiments.