Numerical study and experimental characterization of a two-section polarization-mode dispersion (PMD) compensator suggest a simple feedback algorithm to obtain PMD compensation. The experimental results of compensated...
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Numerical study and experimental characterization of a two-section polarization-mode dispersion (PMD) compensator suggest a simple feedback algorithm to obtain PMD compensation. The experimental results of compensated optical pulses are reported.
With the rapid development of wearable devices, this paper improves the main step counting algorithm, and adds the functions of computing and displaying the data such as velocity, mileage and calorie consumption. The ...
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ISBN:
(纸本)9781538635735
With the rapid development of wearable devices, this paper improves the main step counting algorithm, and adds the functions of computing and displaying the data such as velocity, mileage and calorie consumption. The algorithm mainly includes the step algorithm of human motion data acquisition and gesture analysis, the filter algorithm based on Fourier decomposition, the filter algorithm based on mean value algorithm and the energy consumption algorithm for calories. These algorithms are written through the core processor. And single chip microcomputer will collect the calculated movement steps, mileage, current calories consumption and other motion data through Bluetooth components to the mobile phone, to achieve the monitoring of human movement. It has the characteristics of high precision, low redundancy and rich function.
Terrestrial laser scanners provide accurate and detailed point clouds of forest plots, which can be used as an alternative to destructive measurements during forest inventories. Various specialized algorithms have bee...
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Terrestrial laser scanners provide accurate and detailed point clouds of forest plots, which can be used as an alternative to destructive measurements during forest inventories. Various specialized algorithms have been developed to provide automatic and objective estimates of forest attributes from point clouds. The step (Snakes for Tuboid Extraction from Point cloud) algorithm was developed to estimate both stem diameter at breast height and stem diameters along the bole length. Here, we evaluate the accuracy of this algorithm and compare its performance with two other state-of-the-art algorithms that were designed for the same purpose (i. e., the CompuTree and SimpleTree algorithms). We tested each algorithm against point clouds that incorporated various degrees of noise and occlusion. We applied these algorithms to three contrasting test sites: (1) simulated scenes of coniferous stands in Newfoundland (Canada), (2) test sites of deciduous stands in Phalsbourg (France), and (3) coniferous plantations in Quebec, Canada. In most cases, the step algorithm predicted diameter at breast height with higher R2 and lower RMSE than the other two algorithms. The step algorithm also achieved greater accuracy when estimating stem diameter in occluded and noisy point clouds, with mean errors in the range of 1.1 cm to 2.28 cm. The CompuTree and SimpleTree algorithms respectively produced errors in the range of 2.62 cm to 6.1 cm and 1.03 cm to 3.34 cm, respectively. Unlike CompuTree or SimpleTree, the step algorithm was not able to estimate trunk diameter in the uppermost portions of the trees. Our results show that the step algorithm is more adapted to extract DBH and stem diameter automatically from occluded and noisy point clouds. Our study also highlights that SimpleTree and CompuTree require data filtering and results corrections. Conversely, none of these procedures were applied for the implementation of the step algorithm.
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