An in-vehicle information system includes a camera and a controller that accept gesture input. A controller receives frames of video data and generates trajectory data for a movement of a hand in the video data. The controller uses a first hidden Markov model (HMM) to decode a sequence of strokes from the trajectory data, removes a starting and ending stroke to form an edited stroke sequence, and re-normalizes the strokes in the edited stroke sequence. The controller uses a second HMM corresponding to a predetermined set of characters to identify a character corresponding to the re-normalized edited stroke sequence.