WNCG Ph.D. student Chao Jia and his advisor Prof. Brian L. Evans received a Top 10% Paper Award at the 14th IEEE Multimedia Signal Processing Workshop held in September. Their paper was entitled Probabilistic 3D Motion Estimation for Rolling Shutter Video Rectification from Visual and Inertial Measurements. This paper addressed the long-standing problem of warping artifacts that appear during video recording on smart phones and many other handheld digital cameras. In these handheld products, the camera does not have a hardware shutter in order to save cost and reduce weight and physical volume. During video acquisition, light continually impinges on the camera's image sensor array. The sensor array is read one row at a time, which causes the sensor row to be reset. This arrangement is called a rolling shutter. The amount of time that elapses from reading the first row to reading the last row can lead to significant warping artifacts in the video frame, especially when there is fast motion in the scene relative to the camera. In this paper, the authors fuse two sources of information to reduce rolling shutter artifacts. The first source is the gyroscope readings, which indicate camera rotation. These readings have to be synchronized with the video camera and interpolated to match the much higher rate at which rows in the image sensor array are read. The second source is finding and tracking feature points in the video frames. By developing a framework based on extended Kalman filtering, the authors were able to correct warping artifacts in several test video sequences taken on a smart phone. View the award here (http://www.mmsp2012.org/top10p_paper_award.html) and the paper here (http://users.ece.utexas.edu/~bevans/papers/2012/rolling/index.html).
