An optical flow sensor is presented that directly measures the
translational component of the optical flow experienced by the sensor
while it is on a moving platform. The translational optical flow is
measured by using a gyro to measure the platform's angular rates and then
incorporating these angular rates in the optical flow computations in a
manner that bypasses lags in the optical flow sensor measurement. In one
embodiment, individual "velocity report" optical flow measurements have
their rotational component removed before these velocity reports are
utilized in the remainder of the optical flow algorithm. In another
embodiment, a movable window and shifting techniques are used to form a
windowed image that has no rotational optical flow components. In another
embodiment, an optical flow sensor is mounted on a gimbal and held to
point in one direction even as the platform on which the optical flow
sensor is mounted moves.