A hybrid-type bi-optical bar code symbol reading system has a vertical housing section with a vertical scanning window and a horizontal housing section with a horizontal scanning window from which laser scanning planes are projected and intersect within a 3D scanning volume defined between the vertical and horizontal scanning windows. An automatic object edge-motion detection subsystem is provided for detecting the entry and exit of objects at the edge of the 3D scanning volume and generating control signals in response thereto. A digital imaging subsystem is supported within the system housing and automatically projects a field of view (FOV) within the 3D scanning volume in response to control signals generated by the automatic object edge-motion detection subsystem and timer settings managed by a system controller.