Hybrid Video Stabilization for Mobile Vehicle Detection on SURF in Aerial Surveillance

Detection of moving vehicles in aerial video sequences is of great importance with many promising applications in surveillance, intelligence transportation, or public service applications such as emergency evacuation and policy security. However, vehicle detection is a challenging task due to global camera motion, low resolution of vehicles, and low contrast between vehicles and background. In this paper, we present a hybrid method to efficiently detect moving vehicle in aerial videos. Firstly, local feature extraction and matching were performed to estimate the global motion. It was demonstrated that the Speeded Up Robust Feature (SURF) key points were more suitable for the stabilization task. Then, a list of dynamic pixels was obtained and grouped for different moving vehicles by comparing the different optical flow normal. To enhance the precision of detection, some preprocessing methods were applied to the surveillance system, such as road extraction and other features. A quantitative evaluation on real video sequences indicated that the proposed method improved the detection performance significantly

Passive Localization for Mixed-Field Moving Sources

Due to the mobility of underwater equipment, high-precision underwater positioning technology will face two technical challenges: dealing with mixed-field signals composed of near-field signals and far-field signals; adapting to variable component of mixed-field signals considering the mobility of equipment. Under this condition, an effective method based on MUSIC is addressed in this paper. After distinguishing far-field signal subspace from mixed-field signal subspace, estimations of DOAs and powers of far-field sources are carried out. Then the corresponding far-field and noise signal components can be eliminated from the signal subspace. After that, based on path-following algorithm, modified 2D-MUSIC is performed for DOA and range estimations of near-field sources. The performance of the proposed method is verified and compared with the other methods through computer simulations. Reasonable classification of source types and accurate localization estimation can be achieved by using the proposed method

Research on Multi-AUVs Data Acquisition System of Underwater Acoustic Communication Network

In order to meet the needs of large-scale underwater operations, the underwater acoustic communication network emerged, marking a historic moment. At the same time, the development of artificial intelligence has promoted the application of intelligent underwater robots in large-scale underwater operations, and the research on related algorithms has been gradually promoted. Due to the complexity of underwater operations and the difficulty of replacing batteries, the energy efficiency of intelligent underwater robots is particularly important in multi-AUVs data acquisition systems. In view of the energy consumption of multi-AUVs data acquisition systems in water acoustic cluster networks, this paper proposed the AE (A*-Energy) algorithm for multi-AUVs task assignment and path planning. Through the simulation experiment, it was proved that the AE algorithm proposed in this paper can effectively reduce the energy consumption of multi-AUVs data acquisition systems and has good energy efficiency

Symmetrical triangular LFM for underwater acoustic communications

Synchronous detection acts as a key role in underwater acoustic communications. It is discovered that the Symmetrical Triangular Linear Frequency Modulation (STLFM) signal has double energy peaks in their fractional Fourier transform domain and these two peaks have symmetry in their amplitude if the STLFM signal is captured in the accurate time windows for the synchronization. In this paper, we propose a synchronization detection method based on the STLFM. To verify the effectiveness of the proposed method, we apply simulations based on the Bellhop program and sea trial data collected at Wuyuan Bay, Xiamen, China. The results show that the proposed STLFM method outperforms the LFM method

Diving helmet noise spectral estimation based on pitch tracking

Conference Name:2012 International Conference on Systems and Informatics, ICSAI 2012. Conference Address: Yantai, China. Time:May 19, 2012 - May 20, 2012.This paper describes an algorithm for estimating breath noise in deep water diving helmet, which is the primary factor responsible for speech degradation. The algorithm consists of two parts: speech front-end detection based on pitch tracking, and noise estimation combined with energy criterion. Experimental results are reported and confirm the algorithm in efficiency and robustness. 漏 2012 IEEE

The Source Areas and Migratory Pathways of the Fall Armyworm Spodoptera frugiperda (Smith) in Sichuan Province, China

The Sichuan Province, located in Southwest China, is one of China’s main maize-producing areas, and is also an important node along the north-south migratory pathways that pests follow within China. After its invasion, the fall armyworm (FAW), Spodoptera frugiperda (Smith), was found in 70.81% of all counties in Sichuan. However, FAW source areas and their migratory pathways into Sichuan remain unclear. This study simulated FAW sources and their migratory pathways into Sichuan during 2020 and 2021 using the trajectory simulation platform HYSPLIT with flight behavior parameters. Additionally, the seasonal horizontal wind field was also analyzed with the meteorological graphics processing software GrADS. The results showed that sporadic FAW migration into Sichuan began in April. By May, FAWs were found in much of the Sichuan Basin and moved further north and west in June. Except for year-round breeding areas, FAW sources varied monthly and expanded northward and eastward. The source areas were concentrated in Yunnan, Guizhou, Chongqing, and Myanmar on the western pathway of national migration and also in Vietnam, Guangxi, and Hunan of the eastern pathway. At various times, parts of Sichuan have also served as sources for other parts of Sichuan. FAWs migrated to Sichuan from the source areas via 6 potential pathways, 1 pathway into southwest Sichuan and 5 pathways into the Sichuan basin. The southwestern airflow from the Bay of Bengal, the southeastern airflow controlled by the western Pacific subtropical high, and the local topographically influenced airflow could provide the airflow needed for FAW migration. This work provides new information that can assist the monitoring and warning of the presence of FAW and support integrated management strategies for this pest in Sichuan and throughout China

SNR estimation of LFM signal for the underwater acoustic channel based on improved M2M4

For channel estimation of the communication system, SNR (Signal to Noise Ratio) estimation is a very important parameter. In this paper, we combine the classical Rayleigh and Rician channel with additive white Gaussian noise to simulate the underwater acoustic channel statistical models. Then we apply the SNR estimation method M2M4 (Second order and Fourth order Moment method) for LFM system in underwater acoustic channel. Furthermore, according to the characteristics of both LFM system and channel models, we put forward the improvement of M2M4 based on FRFT (Fractional Fourier Transform) to increase the algorithm performance for underwater acoustic Rayleigh Gaussian channel, Rician Gaussian channel and Ray Tracking channel. ? 2013 by Binary Information Press

A core–shell copper oxides-cobalt oxides heterostructure nanowire arrays for nitrate reduction to ammonia with high yield rate

Electrochemical nitrate reduction to ammonia (NRA) can realize the green synthesis of ammonia (NH3) at ambient conditions, and also remove nitrate contamination in water. However, the current catalysts for NRA still face relatively low NH3 yield rate and poor stability. We present here a core–shell heterostructure comprising cobalt oxide anchored on copper oxide nanowire arrays (CuO NWAs@Co3O4) for efficient NRA. The CuO NWAs@Co3O4 demonstrates significantly enhanced NRA performance in alkaline media in comparison with plain CuO NWAs and Co3O4 flocs. Especially, at −0.23 V vs. RHE, NH3 yield rate of the CuO NWAs@Co3O4 reaches 1.915 mmol h−1 cm−2, much higher than those of CuO NWAs (1.472 mmol h−1 cm−2), Co3O4 flocs (1.222 mmol h−1 cm−2) and recent reported Cu-based catalysts. It is proposed that the synergetic effects of the heterostructure combing atom hydrogen adsorption and nitrate reduction lead to the enhanced NRA performance

Moving target detection using C_SURF registration

Due to the high mobility, rapid deployment and a wide range of monitoring, vehicle detection and tracking system based on low-level mobile platform attract more and more attention. Cameral self-motion, outside interference and other reasons caused by low altitude mobile platforms impact the performance of traditional vehicle detection algorithms. To resolve the above problems, a new method on improved SURF color image stabilization is presented in this paper. From the experimental results, we can see, firstly, compared to other methods, the method proposed by the paper can achieve vehicle detection performance; secondly even in a complex background environment, the method in this paper can effectively detect moving vehicles

Rational design of a pre-lithiated ionogel membrane with enhanced safety and electrochemical performances

Hard carbon is hard to be commercialized due to its low initial efficiency. The irreversible capacity loss usually consumes numerous lithium ions from the electrolyte, leading to an unexpected energy density attenuation. Therefore, effective pre-lithiation methods are extremely desired. Herein, a striking and simple pre-lithiated method was proposed through introducing lithium metal passivation powder into ionogel electrolyte as lithium source. Safety features and electrochemical performances of as prepared ionogel electrolyte were studied systemically. Notably, our work found that the incorporation of lithium metal powder could effectively improve the ionic conductivity, reduce the reactive activation energy, and supplement the lithium-ion loss of electrolyte. The pre-lithiated electrolyte could stand an ultra-high operating potential window of 4.2 V in lithium-ion capacitors. Moreover, our study reveals that the dissociation of the ionic clusters within the ionogel electrolyte favors the electrochemical performances at high temperature. Our optimized device delivered a maximum energy density of 138 Wh kg-1 and a maximum power density of 19339.4 W kg-1 at 60 degrees C. This simple prelithiation method will significantly benefit the rational fabrication of lithium-ion capacitors with high energy density and reasonable safety