On a possibility of pen-tip camera for the reconstruction of handwritings

Toward realization of "writing-life-log," a camera-based handwriting pattern acquisition system is proposed. The camera is attached around the tip of a popular pen and captures frame images around the pen tip continuously. Our problem is the reconstruction of the entire handwriting pattern by video-mosaicing of those frame images with perspective registration of consecutive frames. A key idea is to use microscopic structure of paper surface, called paper fingerprint, for the registration. Specifically, perspective transformation is estimated by using correspondence of SURF keypoints extracted on paper surface. Since the precise structure can be captured stably as the SURF keypoints from the pen-tip camera, thus it is possible to expect accurate registration of video frames.