So far, the only time we had to handle inter-frame processing was for the filtering methods for de-interlacing and smoothing of videos demonstrated in the previous chapter. These methods were not very sophisticated, as they did not aim at extracting useful information, for example, detecting and estimating motion from the video frame sequences.
Motion detection can be loosely defined as the process of detecting changes in the relative position of an object to its background (however, this background is defined) in the consecutive frames of a video. Intuitively, this process could be based on a simple subtraction of these consecutive frames, so that the values of the pixels that change appear brighter than those that remain constant. For various reasons, this simplistic approach is not always successful. In this chapter, we will discuss why.
On the other hand, motion estimation is a more challenging problem; it aims at estimating a set of vectors that...