The result of a histogram backprojection is a probability map that expresses the probability that a given image's content is found at a specific image location. Suppose we now know the approximate location of an object in an image; the probability map can be used to find the exact location of the object. The most probable will be the one that maximizes this probability inside a given window. Therefore, if we start from an initial location and move around iteratively, it should be possible to find the exact object location. This is what is accomplished by the mean shift algorithm.
Using the mean shift algorithm to find an object
How to do it...
The steps for this recipe are as follows:
- Suppose we have identified an object...