Chapter5 -Motion Detection, Segmentation and Wavelets

DIGITAL IMAGE PROCESSING TMM24 43 CHAPTER5 - MOTION DETECTION, D ETECTION, SEGMENTATION AND WAVELETS

Motion Detection •

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Motion detection is the process of detecting a change in position of an object relative to its surroundings or the change in the surroundings relative to an object. Motion detection Often from a static camera. Common in surveillance systems. Often performed on the pixel level only (due to speed constraints).

Motion Detection •

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Motion detection is the process of detecting a change in position of an object relative to its surroundings or the change in the surroundings relative to an object. Motion detection Often from a static camera. Common in surveillance systems. Often performed on the pixel level only (due to speed constraints).

Motion Detection •

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Motion detection plays a fundamental role in any object tracking or video surveillance algorithm, to the extent that nearly all such algorithms start ith motion detection. !ctually, the reliability ith hich potential p otential foreground foreground objects in movement can be identi"ed, directly impacts on the e#ciency and performance level achievable by subse$uent processing stages of tracking and%or recognition. &oever, detecting regions of change in images of the same scene is not a straightforard task since it does not only depend on the features of the foreground elements, but also on the characteristics of the background such as, for instance, the presence of vacillating elements. 'rom this starting point, any detected changed pixel ill be considered as part of a foreground foreground object.

Motion Detection

Motion Detection !SAD" •

! is an algorithm for measuring the similarity beteen to video frames.

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*t "nds the motion by "rstly subtracting the to frames.

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econdly, the absolute value of the latter result is obtained.

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 +hirdly, these dierences are summed to create a simple metric of image motion. -ets take an example, se$uences of frames are employed, the current frame and the next frame are taken into consideration at every computation. +hen, the frames are changed (the next frame becomes present frame and the frame that comes after it becomes the next frame).  +he ! algorithm is reliable because/ its fast, takes less memory, time, and number of steps to achieve the calculation.

Motion Detection !SAD"