Henri Nicolas

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This paper presents a simple and fast method for unsupervised trajectory estimation of multiple moving objects within a video scene. It is entirely based on the motion vectors that are present in compressed H.264/AVC or SVC video streams. We extract these motion vectors, perform robust frame-wise global motion estimation and use these estimates to form(More)
We present in this article a new video watermarking which resists collusion, MPEG4 compression and frame dropping attacks. This scheme is based on video mosaicing. For that, we are going to start by describing the mosaicing technique in order to illustrate the contribution of this technique in video watermarking. In fact, mosaicing allows to select an(More)
This paper presents a new method to estimate in natural video sequences the position of the projection of the light source in the image plane and a shadow segmentation of previously segmented video objects. The proposed method is based on simple geometric constraints between the object, its shadow and the light source location. It requires the segmentation(More)
We present a novel system to perform efficient, compressed domain aided video analysis in the context of traffic surveillance applications. After camera installation, the system initializes by performing two short and fully automatic learning stages to gather information about the background and the principal moving directions in the scene. This knowledge(More)