Abstract: We present a three degree-of-freedom control designed for viewing large documents and images on a mobile device equipped with a camera. Tracking natural features detected in the camera's field of view, we can roughly estimate the motion of the device, using the results to scroll and zoom the current document. Central to our implementation is the manner by which we amplify the motion, allowing the user to scroll through large portions of the document with minimal hand movement. Then, using a Hidden Markov Model, we determine when the user is scrolling, zooming, or some combination of the two, thus providing smoother, more fluid control. We demonstrate a prototype of our 3DOF control that can easily navigate documents that are many times larger than the display area, and show how it might be incorporated into a larger document retrieval application.