In this paper, we address the problem privacy in video surveillance. We propose an efficient solution based on transformdomain scrambling of regions of interest in a video sequence. More specifically, the sign of selected transform coefficients is flipped during encoding. We address more specifically the case of Motion JPEG 2000. Simulation results show that the technique can be successfully applied to conceal information in regions of interest in the scene while providing with a good level of security. Furthermore, the scrambling is flexible and allows adjusting the amount of distortion introduced. This is achieved with a small impact on coding performance and negligible computational complexity increase. In the proposed video surveillance system, heterogeneous clients can remotely access the system through the Internet or 2G/3G mobile phone network. Thanks to the inherently scalable Motion JPEG 2000 codestream, the server is able to adapt the resolution and bandwidth of the delivered video depending on the usage environment of the client.
International audienceThis paper presents a leak isolation methodology using a fitting loss coefficient calibration. Two stages are considered for this purpose: First, the equivalent straight length (ESL) is fixed by an model-base observer designed as an extended Kalman filter. Once the leak is detected, the previous observer is stopped and the second system, based on an algebraic observer, is started with the ESL value fixed by the previous observer. Finally, the estimated leak position is recovered in original coordinates since the observer deal with ESL coordinates. In order to tackle the friction variations problem, the so-called Swamee-Jain equation is embedded explicitly, instead of a constant parameter as in other studies. The approach assumes only flow and pressure sensors at the ends of the duct. Experimental results with data obtained from a plastic pipeline prototype are presented to assess the method efficiency
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