Segmenting an image with the GrabCut algorithm

The previous recipe showed how color information can be useful to segment an image into an area corresponding to specific elements of a scene. Objects often have distinctive colors, and these ones can often be extracted by identifying areas of similar colors. OpenCV proposes an implementation of a popular algorithm for image segmentation—the GrabCut algorithm. GrabCut is a complex and computationally expensive algorithm, but it generally produces very accurate results. It is the best algorithm to use when you want to extract a foreground object in a still image (for example, to cut and paste an object from one picture to another).