In most circumstances, the operator of a vehicle such as an automobile, truck, and the like has adequate visibility for the safe operation of the vehicle. Furthermore, the operator's visibility is enhanced through the well known use of rearview and sideview mirrors. Despite this, however, there are situations when a driver's visibility is limited or eliminated entirely. For example, when a driver is maneuvering a vehicle into a parking space on the side of the road between two other vehicles, the driver is often required to perform one or more iterations of backing up and pulling forward between the two vehicles without contacting either vehicle. The driver, however, generally cannot see that portion of the driver's vehicle that might make such contact. In addition, difficulty is often encountered when the operator of a vehicle is pulling forward towards an obstacle such as when driving into a garage, and the driver has no line of sight to that region of the vehicle that will make contact with the obstacle. This is especially true when, for example, a truck is backing up to a loading dock for the purpose of unloading the truck's contents.
In an attempt to solve problems of this nature, vehicular collision avoidance systems have been developed and are now relatively common. Such systems may include an apparatus for determining the distance between a vehicle and an obstacle in the vehicle's path and apparatus for displaying that distance or at least alerting the operator of an impending collision. For example, U.S. Pat. No. 4,903,004 issued Feb. 20, 1990, and entitled “All-Weather Digital Distance Measuring and Signaling System” describes a distance measuring and signaling system for a vehicle specifically intended for accurately measuring distances from obstructions, such as those behind a truck as it is being backed up. An array of transducer devices having independent sending and receiving capabilities are mounted on a support frame, such as a rear bumper. A pulsed signal emanating from a transistor amplifier circuit is timed as it is converted to an ultrasonic wave signal by each transducer device, is simultaneously emitted and received by the transducer devices, and is returned as a pulsed signal. This signal is returned after bouncing back from an obstruction, and the time of the return is converted into a distance value by digital converter circuitry. The digital converter circuitry in turn sends the signal to a digital display device. U.S. Pat. No. 4,674,073 issued Jun. 16, 1987, and entitled “Reflective Object Detecting Apparatus” describes an apparatus wherein a plurality of ultrasonic transmitting elements and ultrasonic receiving elements are provided and are electrically switched in a sequential manner to allow the existence of an obstacle to be detected. The distance to the object and a particular region at which it is detected is displayed. The ultrasonic transmitting elements and the ultrasonic receiving elements are alternately disposed in a linear array.
Unfortunately, known systems of the type described above generally require the operator to divert his attention from performing functions critical to the safe operation of the vehicle in order to look at the display.
In view of the above, it would be desirable to provide a distance detection and display system which avoids the above described disadvantage by providing a distance display that is easily viewed by an operator of a vehicle so as not to distract the driver from more important driving operations.