Abstract: Methods and devices for processing captured video frames to detect specific changes observable in video using three consecutive video frames. The images in the first video frame are compared with the second frame and the images of the second frame are compared with the third frame to produce two intermediate images which show the first order change observable in video. These interim images are then analyzed. A geometric transformation is found such that when the transformation is applied to one of these intermediate images, the number of pixels which match between the interim is maximized. This geometric transformation, which may include a linear as well as a rotational component, is then applied to one of the intermediate images to result in a transformed image. The transformed image is then subtracted from the other intermediate image to arrive at an end image which shows the second order change or the change in a change observable in video.

Abstract: A method for tracking the location of the tip of the nose with a video camera, and a hands-free computer input device based thereon have been described. According to this invention, a convex shape such as the shape of the tip of the nose, is a robust object suitable for precise and smooth location tracking purposes. The disclosed method and apparatus are substantially invariant to changes in head pose, user preferred seating distances and brightness of the lighting conditions. The location of the nose can be tracked with pixel and sub-pixel accuracy.

Abstract: A method for tracking the location of the tip of the nose with a video camera, and a hands-free computer input device based thereon have been described. According to this invention, a convex shape such as the shape of the tip of the nose, is a robust object suitable for precise and smooth location tracking purposes. The disclosed method and apparatus are substantially invariant to changes in head pose, user preferred seating distances and brightness of the lighting conditions. The location of the nose can be tracked with pixel and sub-pixel accuracy.