Traffic Monitoring

TRAFFIC MONITORING: Optical sensing system improves trafficflow evaluation By SHRUTHI KOMAL GUDIPATI

Why Optical Systems? • Traffic-data measurement systems often used today are induction loops embedded in the pavement and the so-called floatingcar-data technique • Optical systems can overcome these limitations 2

Continued. . . • The variety of optical sensors offers greater flexibility in system development and application • several cameras can be installed at multiple locations to compensate for occlusions

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Continued. . . • able to observe and analyze local and wide-area traffic and automatically generate traffic data • image sequences acquired by these systems can be used to track all the objects that take part in the traffic flow

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The Institute of Computer Science at the Humboldt-Universität zu Berlin (Germany) • testing an integrated optical system for image analysis in traffic monitoring in conjunction with the German Aerospace Center

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Their Goal • develop algorithms for characterizing traffic patterns that can be implemented in programmable logic arrays or in digital signal processors in the camera system itself to support real-time signal processing

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System Requirements • be able to acquire and evaluate traffic image sequences at intersections and along lanes or roads • has to work continuously and reliably • sensor-data fusion 7

Hardware and software components • mechanical and optical components, an image-acquisition system, a hardwarebased image-processing unit, and imageprocessing software implemented in a standard microprocessor

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An integrated optical system

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Components of the system • mechanical and optical components • an image-acquisition system • a hardware-based image-processing unit • an image-processing software implemented in a standard microprocessor 10

FPGA • a high degree of parallelism • a flexible structure • low clock frequency • low power loss 11

Sensor-data fusion • Need to know the spatial relationship between the camera sensors • One kind of fusion -- RANSAC or Random Sample Consensus • Another approach involves augmenting the VIS spectral range of observation by adding a thermal-infrared (TIR) sensor to the system 12

Using epipolar geometry. . .

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Another Problem • the issue of calculating amounts for characterizing traffic flow--the so-called "traffic active area." • invisible routes that are the optimal connections between their points of interest, subconsciously chosen in the same way by most individuals 15

Movement of pedestrians

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REFERENCES •

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1. R.D. Kühne, R.-P. Schäfer, J. Mikat, K.-U. Thiessenhusen, U. Böttger, and S. Lorkowski, Proc. 10th IFAC (Int'l. Fed. of Automatic Control) Symp. on Control in Transportation Systems, Tokyo, Japan (2003). 2. S. Lorkowski, P. Mieth, R.-P. Schäfer, CTRI Young Researcher Seminar, Den Haag (NL), Nov. 11-13, 2005. 3. Xilinx Corp. www.xilinx.com/publications/xcellonline/partners/xc_pdf/xc_nuvation43.pdf. 2005 4. Z. Zhang, Int'l. J. Computer Vision 27, 2, 161, Kluwer Academic Publishers, Boston (1998). BEATE MEFFERT is head of the signal-processing and pattern-recognition group at the Institute of Computer Science, Humboldt-Universitaet zu Berlin; ROMAN BLASCHEK and UWE KNAUER are graduate students at Humboldt-Universitaet zu Berlin, Unter den Linden 6, 10099 Berlin, Germany; e-mail [email protected].

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