Patent ID: 7969586

Claim:
An electronic leveling apparatus for optically measuring a height difference relative to a leveling staff, said apparatus comprising: a telescope including a first optical detector and a first optical system for generating an image on the first optical detector; a camera including a second optical detector and a second optical system for generating an image on the second optical detector, wherein an orientation of the camera is fixed relative to the telescope; a first actuator for rotating both said telescope and said camera in a horizontal plane about a fixed vertical axis of the apparatus; and a controller; wherein the controller is configured to receive a first output signal from said first optical detector and to output a leveling signal representing a detected height difference based on the first output signal from the first optical detector; wherein the second optical system has a depth of focus that is at least twice a depth of focus of the first optical system; and wherein the controller is further configured to receive a second output signal from said second optical detector, to identify a representation of the leveling staff in the second output signal received from the second optical detector, and to control said first actuator based on the identified representation of the leveling staff.