Using the mean shift algorithm to find an object
The result of a histogram backprojection is a probability map that expresses the probability that a given piece of image 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 location will be the one that maximizes this probability inside a given window. Therefore, if we start from an initial location and iteratively move around in an attempt to increase the local probability measure, it should be possible to find the exact object location. This is what is accomplished by the mean shift algorithm.
How to do it...
Suppose we have identified an object of interest here, a baboon's face, as shown in the following image:

This time, we will describe this object by using the hue channel of the HSV color space. This means that we need to convert the image into an HSV one and then extract the hue...