In this chapter, we have seen how to detect features in an image and match them to features in other images. To perform this task, we looked at various algorithms, such as SIFT, SURF, ORB, BRISK, and FREAK, and their pros and cons. We also saw how we can use these to localize specific objects in a scene. There is one restriction to these methods in that the exact object must be present in the scene image to be detected correctly. In the next chapter, we will take a step forward to detect more general classes of objects, such as human beings, faces, hands, and so on.