The situation on the road is given on the left side (traffic sign rotated 90° around a horizontal axis orthogonal to the road). Right part: The black solid line is the time history of the gaze angle in yaw (azimuth); it is zero at the beginning and at the end. The traffic sign is picked up at ~ 17°; it moves to larger angles. After five frames the trajectory of the sign in the image is considered recognized, and a saccade to tracking the center of the sign with the center of the image is commanded. After two cycles (80 ms) with completely blurred images the commanded trajectory is reached, and a new search is started. Six cycles later the traffic sign is recovered (green curve 1 around 0.5 and 0.6 seconds). The fifth image of this sequence (in the tele-camera, not shown) is stored for interpretation, and the saccade back to 0 is started. The whole saccade (forth and back) needs about ¾ of a second.
The video, with the saccade also in slow motion, gives a good impression of the maneuver based on edge extraction with no prior knowledge of the relative position.
Reference
Schiehlen J. 1995: Kameraplattformen für aktiv sehende Fahrzeuge. Kurzfassung