MD-Shots software of shot change detection

The software MD-shots , for "Motion-based Detection of shots" performs the temporal segmentation of a video into shots. It is developed in languages C-ANSI and C++. Prior to any content-based video indexing, it is necessary to build a structured temporal representation of a video into elementary shots. This implies to detect "cuts" and progressive transitions corresponding to shot changes. By progressive transitions, we mean special effects, such as fade-in, fade-out, dissolve, wipe, ...

The proposed method to achieve the video partitioning in elementary shots [1] exploits the temporal coherence, within a same shot, of an appropriate information related to the global dominant motion between two successive images (Fig. 1). The later, represented by a 2D parametric model, is estimated using the Motion-2D [2] software. We consider in fact the temporal evolution of the normalized size of the support associated to the estimated dominant motion. At the time of a "cut", no motion model can correctly describe the transformation between the two succesive images, which leads to a sudden fall of the support size value. At the time of progressive transitions, this fall is less prononced but occurs over a time interval This detection of jumps is carried out by a statistical Hinkley test, whose implementation is simple and efficient. An original asset of the method is to handle the detection of the various kinds of transitions involving only one parameter to be set by the user. Moreover, a same value of this parameter is used for the two types of treated transitions.

To act on the processing rate used, it is possible to specify the first and the last levels considered in the image pyramids. It is also possible to retain a temporal under sampling of the sequence to be processed. According to options selected, we can currently reaches processing rates ranging from 0,6 Hz to 2,6 Hz on a SUN Ultra-Creator station at 300 MHz. This software was transferred to Alcatel-CRC and to Ina. In addition, a licence agreement of commercial exploitation was concluded with the company Arts Video Interactive (insertion in the commercial product marketed MOVIDEO-2 STUDIO).

Example of shot change detection
Figure 1: Partitioning into shots of the "Ajax" video (provided by Ina) : (a) The plot shows the temporal evolution of the normalized size of the support associated to the estimated dominant motion. Comparison of the obtained results with a manually-derived ground-truth is provided. (b) Each detected  shot is represented by a thumbnail image.

[1] P. Bouthemy, M. Gelgon, F. Ganansia. A unified approach to shot change detection and camera motion characterization.   Research Report no 1148, Irisa, november 1997,, Revised version to appear in IEEE Trans. on Circuits and Systems for Video Technology, décembre 1999.

[2] J.-M. Odobez, P. Bouthemy. Robust multiresolution estimation of parametric motion models.  Journal of Visual Communication and Image Representation, 6(4):348-365, December 1995.

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