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At present, the traditional ICP (Iterative Closest Point) algorithm used by TOF (Time-Of-Flight) cameras has the problem of high time-consuming in nearest point search process, resulting in low data update rate. Therefore, based on the characteristics of the data structure of the ICP algorithm, a multi-stage pipeline acceleration system is proposed, and the point cloud registration algorithm used in this system is studied. Firstly, design multiple units to store point cloud data and serve as the main search module. Secondly, make each group of units perform parallel operations, input the stored point clouds into their respective calculation modules, select a model point, traverse all query points, and perform subtraction. Then replace the model point and repeat the process until all model points are calculated. Finally, the query point corresponding to the minimum value in each model point difference data is selected and the model point is output as a point pair to the CPU to complete the final algorithm iteration. The experimental results show that at 30000 points, a single closest point search takes 25.65ms; at 20000 points, a single closest point search takes 11.65ms; at 10000 points, a single closest point search takes 2.88ms. It basically meets the requirements of TOF camera on-orbit measurement for the stability and reliability of point cloud registration and high data update rate.

Cooperative vehicle-infrastructure is one of the most import developing direction of future intelligent transportation system, while digital twin system can record, reproduce, and even deduce the physical system, which could be helpful for the development of cooperative vehicle-infrastructure. In this study, we proposed a 3D digital twin platform of intelligent transportation system based on road-side sensing, a core component of cooperative vehicle-infrastructure system. This platform consists of real road-side sensing unit,3D virtual environment, and the ROS bridge between them, by receiving the sensing results of physical world in real-time, the virtual world can reproduce the compatible road traffic information, such as the type,3D position and orientation of traffic participants.

To ensure the safety of power cables, temperature monitoring of power cables is critical. In view of the shortcomings of some optical fibre measurement products, a long-distance distributed optical fibre sensor is proposed, which has the advantages of high measurement sensitivity, fast response speed, low false alarm rate, large measurement length, and stable operation. The distributed optical fibre vibration sensing measurement equipment is used to monitor the vibration signals along the cable in real time, and the signal changes before and after the breakdown fault are visually displayed by the patio-temporal spectrum diagram, and the vibration signal of the breakdown point is analysed in time and frequency. The performance of the system was tested, and the experiment verified that the temperature measurement accuracy error range of the temperature measurement system is about ± 5 °C, and it has good stability. At the same time, the positioning accuracy is very high, and the fault point can be accurately located. This can avoid the occurrence of cable accidents.

A technique and system of measuring screw thread parameter based on the theory of laser measurement is presented in this paper, which can be carried out the automated measurement of screw thread parameter. An inspection instrument was designed and produced, which included exterior imaging system of optical path, transverse displacement measurement system, axial displacement measurement system, and a module to deal with, control and assess the data in the upper system. The inspection and estimate of the screw thread contour curve were completed by using position sensitive device (PSD) as photoelectric detector to measure the coordinate data of the screw thread contour curve in the transverse section, and using precise raster to measure the axial displacement of the precision worktable under the screw thread test criterion., computer can gives a measured result according to coordinate data of the screw thread obtained by PSD. The relation between measured spot and image is established, and optimum design of the system organization are introduced, including the image length of receiving lens focal length optical system and the choice of PSD , and some main factor affected measuring precision are analyzed. The experimental results show that the measurement uncertainty of screw thread minor diameter can reach 0. 5μm, which can meet most requests for the measurement of screw thread parameter.

When laser-beam passes through non-isothermal and non-isoconcentration gas, measurement result is influenced by different refractive index in gas flow layer. This paper analyses the regularities of index of refraction distribution in gas flow field, presents the factors that effect on the measurement errors, estimates the position errors of the indicating light-spot and modifies the measurement result in laser-beam measure.

As a core component of the proton exchange water electrolyzer system, membrane electrode assemblies degrade due to the corrosion of the material. This creates a loss of interfacial contact necessary for the electron transports and electrochemical reactions, thus decreasing the performance. X-ray diffraction has been demonstrated to be an effective method that readily provides quantitative information about the phase-composition of solid materials. In this study, a group of materials have been selected and tested in the standard conditions for investigating the corrosion mechanisms with X-ray diffraction. The material lattice parameter and the crystal size were examined by X-ray diffraction spectrum.