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To eliminate the problems of large dimensional differences, big semantic gap, and mutual interference caused by hybrid features, in this paper, we propose a novel Multi-Features Guidance Network for partial-to-partial point cloud registration(MFG). The proposed network mainly includes four parts: keypoints' feature extraction, correspondences searching, correspondences credibility computation, and SVD, among which correspondences searching and correspondence credibility computation are the cores of the network. Unlike the previous work, we utilize the shape features and the spatial coordinates to guide correspondences search independently and fusing the matching results to obtain the final matching matrix. In the correspondences credibility computation module, based on the conflicted relationship between the features matching matrix and the coordinates matching matrix, we score the reliability for each correspondence, which can reduce the impact of mismatched or non-matched points. Experimental results show that our network outperforms the current state-of-the-art while maintaining computational efficiency., Comment: preprint version, the final version is accepted by Neural Computing and Applications and is available online at https://doi.org/10.1007/s00521-021-06464-y

Unobscured reflective optical systems with a wide field of view (FOV) have significant application values. However, the aberration increases with the increase of the system FOV, so a wide FOV system is difficult to design. In this paper, a design method that is effective in achieving off-axis three-mirror systems with ultrawide FOV is proposed. In this method, the system FOV is expanded stepwise in the design process, and the surface optical freeform polynomial terms are extended based on the judgment of image quality and some constraint conditions, and to obtain a prospective ultrawide FOV system. A freeform off-axis three-mirror imaging system with a focal length of 1000 mm, an F-number of 10, and an ultrawide FOV of 80°×4° is designed as an example. This design result shows that the system has a high imaging quality of RMS wavefront error value of 0.040λ(λ=0.633 μm), and it demonstrates that the method is effective in achieving off-axis three-mirror systems with an ultrawide FOV.

Energy is the main driving force of economic development and social progress, and the relationship between its production and supply directly determines the destiny of the country. As to the new urban Energy Internet demonstration project, the characteristics and elements of the new urban Energy Internet are analyzed in this paper, and then the overall framework and information integration framework of the new urban Energy Internet demonstration project is proposed. Finally the overall framework and functional requirements of Energy Internet comprehensive management and service platform and the perception layer equipment are proposed, which can provide technical support and framework guidance for the development of new urban Energy Internet business.

As an important light absorbing material, space extinction black paint has been widely used for space stray light suppression structures. This is usually not compatible with the Lambert diffusion law. Therefore, in order to describe the light scattering characteristics of a stray light suppressed structure surface accurately, bidirectional reflection distribution data at different angles and wavelengths are obtained by experimental measurements. Then a multivariate and multiparameter spectral bidirectional reflection distribution function model is established according to the characteristics of experimental data, and the parameters of the model are fitted accurately based on the Newton descent method. The quantitative evaluation of model error is completed by comparatively analyzing the measured data and the model data. The calculated model error is 3.07%, which proves the accuracy of the proposed parametric model. This model can provide important technical support for the design and evaluation of a space stray light suppression system.