Urban video surveillance from airborne and ground-based platforms

Feng

2022

Sensors

Inspired by the Ormia Ochracea hearing mechanism, a new direction of arrival estimation using multiple antenna arrays has been considered in spatially colored noise fields. This parasitoid insect can locate s cricket’s position accurately using the small distance between its ears, far beyond the standard array with the same aperture. This phenomenon can be understood as a mechanical coupled structure existing between the Ormia ears. The amplitude and phase differences between the received signals are amplified by the mechanical coupling, which is functionally equivalent to a longer baseline. In this paper, we regard this coupled structure as a multi-input multi-output filter, where coupling exists between each pair of array elements. Then, an iterative direction-finding algorithm based on fourth-order cumulants with fully coupled array is presented. In this manner, the orientation of the mainlobe can direct at the incident angle. Hence, the direction-finding accuracy can be improved in all possible incident angles. We derive the Cramér-Rao lower bound for our proposed algorithm and validate its performance based on simulations. Our proposed DOA estimation algorithm is superior to the existing biologically inspired direction-finding and fourth-order cumulants-based estimation algorithms.

Section: Introductionmentioning

confidence: 99%

A High-Precision Algorithm for DOA Estimation Using a Long-Baseline Array Based on the Hearing Mechanism of the Ormia Ochracea

Feng

2022

Sensors

“…In recent years, direction-finding has been used widely in many civil areas, such as spectrum monitoring, navigation and disaster relief [1][2][3][4][5][6]. The basic principle is to estimate the phase difference between two arrival signals and compute the direction of arrival (DOA) with the baseline length and signal frequency [7].…”

Section: Introductionmentioning

confidence: 99%

Biologically inspired direction‐finding for short baseline

Feng

2021

IET Radar Sonar & Navi

The optimal implementation for a biologically inspired coupling structure to overcome the limitation of short baseline direction-finding is determined. This approach is inspired by the Ormia ochracea, a parasitoid insect living in North America. It can locate the crickets' call accurately with the very small distance between its ears far beyond the accuracy of an interferometer with the same baseline. This outstanding performance depends on the mechanical coupling in its auditory system. The first research focus is on the mechanism of the coupling structure, considering not only the amplification on phase difference but also the effect on output power, which leads to the performance improvement in comparison with the traditional method. Then, the biologically inspired coupling structure is optimised to achieve the best direction-finding performance in crickets' sound frequency, reducing the estimation error by 75% when the signal incident at boresight. To implement the actual coupling structure with optimal direction-finding performance, both the analogue circuit and the digital filter implementation are discussed, and the latter attains the theoretical optimal performance. Finally, a directionfinding system prototype is carried out to verify the advantage of digitally implemented coupling structure, and the measurement result approximates the corresponding Cram� er-Rao lower bound.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

“…From the 1990s, researchers had explored a new and improved road traffic surveillance technology -an airborne traffic surveillance system (ATSS) (Angel et al, 2002a(Angel et al, , 2003Cohen and Medioni, 1998;Coifman et al, 1999;Kumar et al, 2001;Parameswaran et al, 1997;Redding et al, 2005;Srinivasan et al, 2004). As noted in Coifman et al (2006), airborne platforms, also called unmanned aerial vehicles (UAVs), can cover a large area and focus resources.…”

Section: Introductionmentioning

confidence: 99%

Vehicle flow detection in real-time airborne traffic surveillance system

Luo

Transactions of the Institute of Measurement and Control

et al. 2011

Compared with the ground-based traffic surveillance systems, the airborne platform takes advantage of convenience and low cost. In most of the existing aerial-based systems, the airborne platform is only responsible for data collection and the ground station is in charge of all data processing for vehicle detection. However, such architecture has a low real-time performance unless with the support of specifically constructed wireless networks. This paper proposed an airborne traffic surveillance system, which can detect vehicles in real time with only a general narrowband wireless network support. In our system, the airborne platform not only gathers video information but also carries out data pre-processing, and only the useful data is transferred to the ground via a GPRS/EDGE network. Moreover, more accurate vehicle flow detection with a false-alarm reduction module is performed on the ground station. Experimental results preliminarily show that the system can achieve real-time vehicle flow detection with a high detection rate and a low false-alarm rate.