OBJECT DETECTION APPARATUS

• US 3,681,750 A
• Filed: 07/02/1970
• Issued: 08/01/1972
• Est. Priority Date: 07/02/1970
• Status: Expired due to Term

• Current Assignee: Vincent E. Larka
• Original Assignee: Vincent E. Larka
• Inventors: Larka, Vincent E.
• Primary Examiner(s): Farley, Richard A.
• Application Number:
  US05/051,758
• Time in Patent Office: 761 Days
• Field of Search: 340/1R,1T,6R,16R,15,34,31R,258D,261
• US Class Current: 367/135
• CPC Class Codes: G08B 1/08 using electric transmission ; transformation of alarm signals to electrical signals from a different medium, e.g. transmission of an electric alarm signal upon detection of an audible alarm signal
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes
• CPC Class Codes: G08G 1/167 Driving aids for lane monitoring, lane changing, e.g. blind spot detection

Abstract

A passive ultrasonic vehicle detection apparatus for use with a vehicle such as an automobile, truck, or bus for detecting and indicating the presence of other vehicles in predetermined regions rearward of the subject vehicle, for example, in travel lanes adjacent to the travel lane of the subject vehicle or in so-called '"'"''"'"''"'"''"'"'blind'"'"''"'"''"'"''"'"' zones of the subject vehicle. When a vehicle is present in one of the adjacent lanes or in a blind zone, signals including ultrasonic signals which are generated inherently by the vehicle, for example, due to a combination of factors such as engine and body vibrations, and engine and tire noises, are received by a frusto-conical signal-receiving horn mounted in a rearward location of the subject vehicle and applied to a piezoelectric crystal transducer. The piezoelectric transducer has a predetermined resonant frequency equal to the frequency of particular ultrasonic signals generated inherently by all existing engine-driven road vehicles. The piezoelectric transducer operates in response to the various signals received from the frusto-conical signal-receiving horn to produce an electrical output voltage which is greatest for ultrasonic signals of the predetermined resonant frequency. The output voltage produced by the piezoelectric transducer is then applied to a resonant circuit tuned to the predetermined resonant frequency to achieve the desired system bandwidth. The output signal produced by the resonant circuit is amplified and applied to an astable multivibrator which operates to produce a train of output pulses for periodically applying the vehicle battery voltage to an integrator circuit. The integrator circuit operates to integrate the voltage pulses received thereby and to operate a driver circuit when a predetermined threshold voltage level is achieved. The driver circuit operates a lamp or other indicator to indicate the presence of the vehicle in the adjacent lane or blind zone.

Claims

1. A passive ultrasonic object detection apparatus associated with a first object for detecting and indicating the presence of another object in a region of surveillance adjacent to the first object, said another object inherently generating signals including ultrasonic signals, said apparatus comprising signalreceiving means for receiving the signals inherently generated by said another object when said another object is present in the predetermined region of surveillance adjacent to said first object, said signal-receiving means receiving said signals only when said another object is present in said predetermined region of surveillance, said predetermined region of surveillance having a geometrical configuration determined by said signal-receiving means;

and processing means coupled to the signal-receiving means for processing the ultrasonic signals received by the signalreceiving means to provide an indication of the presence of said another object in the predetermined region of surveillance, said processing means comprising an ultrasonic transducer having a predetermined resonant frequency and arranged to receive the signals received by the signal-receiving means, said ultrasonic transducer being operable in response to the ultrasonic signals received from the signal-receiving means to produce an output voltage which is greatest for ultrasonic signals of the predetermined resonant frequency; and

circuit means connected to the ultrasonic transducer and operable in response to the output voltage produced by the ultrasonic transducer to produce an output signal having a predetermined amplitude and duration indicative of the presence of said another object in the predetermined region of surveillance, said circuit means comprising tuned resonant circuit means connecTed to the ultrasonic transducer and having a tuned resonant frequency equal to the resonant frequency of the ultrasonic transducer, said tuned resonant circuit means being operable in response to the output voltage produced by the ultrasonic transducer to produce an output signal of a predetermined bandwidth;

amplifier means connected to the tuned resonant circuit means and operable to amplify the output signal produced by the tuned resonant circuit means to produce an amplified output signal having a predetermined voltage gain;

pulse circuit means connected to the amplifier means and operative in response to the amplified output signal produced by the amplifier means to produce a series of output pulses of a predetermined frequency;

dc voltage supply means adapted to produce a dc voltage of a predetermined amplitude;

switching circuit means connected to the pulse circuit means and to the dc voltage supply means and operative in response to the series of output pulses produced by the pulse circuit means to switch the dc voltage produced by the dc voltage circuit means on and off at the predetermined frequency of the series of output pulses produced by the pulse circuit means thereby to produce a series of output pulses of the same frequency as the series of output pulses produced by the pulse circuit means and having an amplitude equal to the amplitude of the dc voltage produced by the dc voltage supply means; and

integrator circuit means connected to the switching circuit means and operable in response to the series of output pulses produced by the switching circuit means to integrate said pulses and to produce an output signal having a predetermined amplitude and duration indicative of the presence of said another object in the predetermined region of surveillance.

2. A passive ultrasonic object detection apparatus in accordance with claim 1, further comprising:

output means connected to the integrator circuit means and operable in response to the output signal produced by the integrator circuit means to provide a sensible indication of the presence of said another object in the predetermined region of surveillance.

3. A passive ultrasonic object detection apparatus in accordance with claim 1 wherein said ultrasonic transducer is a piezoelectric crystal transducer.

4. A passive ultrasonic object detection apparatus in accordance with claim 3 wherein said pulse circuit includes an astable multivibrator circuit.

5. A passive ultrasonic object detection apparatus in accordance with claim 4 wherein:

said signal-receiving means includes a horn member having a frustum configuration; and

said predetermined region of surveillance has essentially a frustum configuration.

6. A passive ultrasonic object detection apparatus in accordance with claim 5, further comprising:

output means connected to the integrator circuit means and operable in response to the output signal produced by the integrator circuit means to provide a sensible indication of the presence of said another object in the predetermined region of surveillance.

7. A passive ultrasonic object detection apparatus in accordance with claim 6 wherein said another object is an engine-driven vehicle.

8. A passive ultrasonic object detection apparatus in accordance with claim 6 wherein said first object and said another object are both engine-driven vehicles and wherein said dc voltage supply means includes a storage battery carried by said first engine-driven vehicle.