1. Implement the Harris Corner Detector with sub-pixel accuracy with cv2.
2. Play with a few different pre-trained Haar Cascade classifiers with cv2 and try to detect multiple faces from images.
3. Use the FLANN-based approximate nearest-neighborhood matcher instead of BFMatcher to match the images with books with cv2.
4. Compute the SURF keypoints and use them for image matching with cv2.