An Assessment of a Low-Cost Visual Tracking System (VTS) to Detect and Compensate for Patient Motion During SPECT

This article presents an approach for determining suitable camera view poses for inspection of surface tolerances based on visual tracking of the tool movements performed by a skilled worker. Automated surface inspection of a workpiece adjusted by manual operations depends on manual programming of the inspecting robot, or a timeconsuming exhaustive search over the entire surface. The proposed approach is based on the assumption that the tool movements of the skilled worker coincide with the most relevant regions of the underlying surface of the workpiece, namely the parts where a manual process has been performed. The affected region is detected with a visual tracking system, which measures the motion of the tool using a low-cost RGBD-camera, a particle filter, and a CAD model of the tool. The main contribution is a scheme for selecting relevant camera view poses for inspecting the affected region using a robot equipped with a high-accuracy RGBDcamera. A principal component analysis of the tracked tool paths allows for evaluating the view poses by the Hotelling’s T-squared distribution test in order to sort and select suitable camera view poses. The approach is implemented and tested for the case where a large ship propeller blade cast in NiAl bronze is to be inspected by a robot after manual adjustments of its surface.

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Optimal design of the solar tracking system of parabolic trough concentrating collectors

International Journal of Low-Carbon Technologies ◽

10.1093/ijlct/ctaa065 ◽

2020 ◽

Vol 15 (4) ◽

pp. 613-619

Author(s):

Li Kong ◽

Yunpeng Zhang ◽

Zhijian Lin ◽

Zhongzhu Qiu ◽

Chunying Li ◽

...

Keyword(s):

Numerical Simulation ◽

Solar Radiation ◽

Tracking System ◽

Low Cost ◽

Parabolic Trough ◽

The North ◽

Tracking Mode ◽

Solar Tracking ◽

East West

Abstract The present work aimed to select the optimum solar tracking mode for parabolic trough concentrating collectors using numerical simulation. The current work involved: (1) the calculation of daily solar radiation on the Earth’s surface, (2) the comparison of annual direct solar radiation received under different tracking modes and (3) the determination of optimum tilt angle for the north-south tilt tracking mode. It was found that the order of solar radiation received in Shanghai under the available tracking modes was: dual-axis tracking > north-south Earth’s axis tracking > north-south tilt tracking (β = 15°) > north-south tilt tracking (β = 45) > north-south horizontal tracking > east-west horizontal tracking. Single-axis solar tracking modes feature simple structures and low cost. This study also found that the solar radiation received under the north-south tilt tracking mode was higher than that of the north-south Earth’s axis tracking mode in 7 out of 12 months. Therefore, the north-south tilt tracking mode was studied separately to determine the corresponding optimum tilt angles in Haikou, Lhasa, Shanghai, Beijing and Hohhot, respectively, which were shown as follows: 18.81°, 27.29°, 28.67°, 36.21° and 37.97°.

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