Current Issue : July - September Volume : 2019 Issue Number : 3 Articles : 5 Articles
Video summarization aims to provide a compact video representation while preserving the essential activities of the\noriginal video. Most existing video summarization approaches relay on identifying important frames and optimizing\ntarget energy by a global optimum solution. But global optimum may fail to express continuous action or realistically\nvalidate how human beings perceive a story. In this paper, we present a bottom-up approach named clip growing for\nvideo summarization, which allows users to customize the quality of the video summaries. The proposed approach\nfirstly uses clustering to oversegment video frames into video clips based on their similarity and proximity.\nSimultaneously, the importance of frames and clips is evaluated from their corresponding dissimilarity and\nrepresentativeness. Then, video clips and frames are gradually selected according to their energy rank, until reaching\nthe target length. Experimental results on SumMe dataset show that our algorithm can produce promising results\ncompared to existing algorithms. Several video summarizations results are presented in supplementary material....
In this paper, we propose an optical transmission system of 128 quadrature amplitude\nmodulation for dense wavelength division multiplexing. In such a system, Gaussian optical\nfiltering is used to get an appropriate photonic carrier. Theoretical analysis and simulation\ncomputation show that the modulated multi-carrier photonic signals with the wavelength spacing\nof 0.7 nm can transmit for over 80 km with the standard single mode fiber. Using digital signal\nprocessing algorithms to compensate the transmission impairments, the transmission rate of the\nsingle-carrier photonic signal can reach up to 904 Gbps and the spectral efficiency of the\ntransmission can reach up to 10.33 bps/Hz. When this technology is applied to a dense wavelength\ndivision multiplexing system with N channels, the huge message capacity of N Ã? 904 Gbps can be\nrealized. Furthermore, we find that the bit error rate and the error vector magnitude are similarly\ninfluenced by the optical signal-to-noise ratio and the bandwidth of the Gaussian optical filter. The\ninfluence presents mostly a synchronization trend with the change of the optical signal-to-noise\nratio and the bandwidth of Gaussian optical filter....
As one of the important scientific instruments of lunar exploration, the Lunar Penetrating\nRadar (LPR) onboard Chinaâ??s Changâ??E-3 (CE-3) provides a unique opportunity to image the lunar\nsubsurface structure. Due to the low-frequency and high-frequency noises of the data, only a few\ngeological structures are visible. In order to better improve the resolution of the data, band-pass\nfiltering and empirical mode decomposition filtering (EMD) methods are usually used, but in\nthis paper, we present a mathematical morphological filtering (MMF) method to reduce the noise.\nThe MMF method uses two structural elements with different scales to extract certain scale-range\ninformation from the original signal, at the same time, the noise beyond the scale range of the two\ndifferent structural elements is suppressed. The application on synthetic signals demonstrates that\nthe morphological filtering method has a better performance in noise suppression compared with\nband-pass filtering and EMD methods. Then, we apply band-pass filtering, EMD, and MMF methods\nto the LPR data, and the MMF method also achieves a better result. Furthermore, according to the\nresult by MMF method, three stratigraphic zones are revealed along the roverâ??s route....
In array signal processing, the direction of arrivals (DOAs) of the received signals are estimated\nby measuring the relative phases among antennas; hence, the estimation performance is reduced\nby the inconsistency among antennas. In this paper, the DOA estimation problem of the uniform\nlinear array (ULA) is investigated in the scenario with phase errors among the antennas, and a\ndiagonal matrix composed of phase errors is used to formulate the system model. Then, by using the\ncompressed sensing (CS) theory, we convert the DOA estimation problem into a sparse reconstruction\nproblem. A novel reconstruction method is proposed to estimate both the DOA and the unknown\nphase errors, iteratively. The phase errors are calculated by a gradient descent method with the\ntheoretical expressions. Simulation results show that the proposed method is cost-efficient and\noutperforms state-of-the-art methods regarding the DOA estimation with unknown phase errors....
The goal of this study was to develop an impact-echo device that can conduct automatic\noscillation tests, process signals rapidly, and apply it to concrete object anomaly analysis. The system\npresented in this study comprises three parts, namely the impact device, the oscillator circuit,\nand signal processing software. The design concept of the impact-echo device was inspired by\na pendulum clock, and its implementation used a nondestructive wooden hammer instead of a\nconventional manual steel hammer. In this study, we used a pulse generator in the adjustable\noscillator circuit to produce delayed changes. The delayed changes would activate the wooden\nhammer that struck the surface of the object. To process the signal, our lab used a built-in sound card\nin the computer to transfer the reflection soundwave from striking the wall to MATLAB software to\nanalyze the energy of the frequency spectrum. This was conducted to evaluate whether the object\ncontained anomalies and, if so, to determine the location of the anomalies to serve as a reference for\nreal-life implementation....
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