Ultrasonic detection system for safety of vehicle passengers

• US 5,764,136 A
• Filed: 06/23/1997
• Issued: 06/09/1998
• Est. Priority Date: 03/27/1996
• Status: Expired due to Fees

• Current Assignee: Her Majesty The Queen In Right of Canada As Represented By The Minister of Industry (The Republic of Canada)
• Original Assignee: Her Majesty The Queen In Right of Canada As Represented By The Minister of Industry (The Republic of Canada)
• Inventors: Harron, Brian
• Primary Examiner(s): Hofsass, Jeffery A.
• Assistant Examiner(s): TWEEL JR, JOHN ALEXANDER
• Application Number:
  US08/880,398
• Time in Patent Office: 351 Days
• Field of Search: 340/435, 340/433, 340/436, 340/904, 367/909, 367/140, 367/112
• US Class Current: 340/435
• CPC Class Codes: B60Q 1/52 for indicating emergencies
• CPC Class Codes: G01S 15/04 Systems determining presence of a target
• CPC Class Codes: G01S 15/87 Combinations of sonar systems
• CPC Class Codes: G01S 7/52004 Means for monitoring or calibrating short-range imaging G01S7/5205

Abstract

This invention relates to a new and useful system and method of ultrasonic detection for use on in the monitoring of the danger zone of a vehicle. The system comprises at least one sensor, an analog and digital integrated circuit, a power driver and a microprocessor. The microprocessor is programmed to control the sensors, to receive a plurality of signals from the sensors, establish and store an initial reference image, monitor a second plurality of signals received from a continuous scan of the sensors, establish a data set for the second plurality of signals, compare the data set with the initial reference image and return an alarm output if a variation is detected.

Claims

1. An ultrasonic system for use in monitoring a danger zone of a vehicle, said system comprising:

one or more transducers;

circuit means for analog to digital signal conversion of acoustic echoes of signals from said transducers and to provide digital information corresponding to said acoustic echoes; and

a processor programmed for controlling said transducers, said processor programmed to, upon receiving said digital information corresponding to a sequence of digitized acoustic echoes from said circuit means for analog to digital conversion;

a) generate from said information, an initial reference data set representing a pattern of distances, the pattern of distances corresponding to echoes received as reflections from objects at plurality of locations in the danger zone from said one or more transducers;

(b) establish and store said initial reference data set representing objects detected in said danger zone when said vehicle becomes stationary,

(c) monitor a subsequent sequence of digitized acoustic echoes received from said transducers,

(d) generate from said subsequent sequence of digitized acoustic echoes a second data set representing a pattern of distances, the pattern of distances corresponding to echoes receieved as reflections from objects at plurality of locations from said one or more transducers;

(e) compare said second data set with said initial reference data set and,

(f) return an alarm output if a variation greater than a predetermined value between said initial reference data set and said second data set is detected.

2. The system of claim 1 wherein said one ore more transducers operate at a beam width in the range of 60 degrees to 100 degrees conical.

3. The system of claim 1, including two transducers arranged to overlap their respective areas of coverage to provide signal redundancy, a broad coverage area and fault detection.

4. The system according to claim 1 including a test and set-up board for calibration and set-up of the system.

5. The system according to claim 1 including power means to operate the system.

12. The system according to claim 1 wherein said transducer comprises a piezoelectric ultrasonic transducer.

14. An ultrasonic system for use in the monitoring of a danger zone of a vehicle, as defined in claim 1, wherein the generation of the initial reference data set representing a pattern of distances includes the steps of:

a) sending a first signal from said microsequencer to said transducer, said transducer in response to said first signal emitting a first burst of pulsed energy towards said danger zone;

b) after a first predetermined time t₁, receiving echoes reflected from an object in a path of travel of said pulsed energy;

c) said transducers generating corresponding electrical signals;

d) routing said signals to said circuit means for analog to digital conversion;

e) after a second predetermined time t₂, receiving echoes reflected from a different object in a path of travel of said pulsed energy;

f) said transducers generating corresponding electrical signals; and

,

g) routing said signals to said circuit for analog to digital conversion.

6. An ultrasonic system for use in the monitoring of a danger zone of a vehicle when stationary, to detect persons or objects within said danger zone, said system comprising:

two ultrasonic transducers operating at a beam width in the range of 60 degrees to 100 degrees conical, said transducers arranged on said vehicle to overlap in their respective areas of coverage to provide signal redundancy and fault detection;

circuit means for analog to digital signal conversion of acoustic echoes of signals from said transducers;

power means to operate the system;

a test and set-up board for calibration and set-up of the system; and

a microsequencer programmed for controlling said transducers, said microsequencer is programmed to, upon receiving a sequence of digitized acoustic echoes from said transducers;

a) generate from said digitized acoustic echoes an initial reference data set representing a a pattern of distances,

(b) establish and store said initial reference data set defining objects in said danger zone when the vehicle is stationary,

(c) monitor a subsequent sequence of digitized acoustic echoes of signals from said transducers,

(d) generate from said subsequent sequence of digitized acoustic echoes a second data set representing a pattern of distances,

(e) establish said second data set and compare said second data set with said initial reference data set and,

(f) return an alarm output if a variation greater than a predetermined value between said initial reference data set and said second data set is detected.

8. The method of claim 6 including provision of an initialization process each time a door of said vehicle is opened, said initialization process comprising the steps of:

performing a self-test operation on said system to ensure said transducers are functional;

clearing said stored initial reference data set; and

initiating said method.

9. The method of claim 6 wherein said initial reference data set is obtained by the steps of:

sending a signal from said microsequencer to said transducer;

said transducer emitting a plurality of cycles of pulsed energy towards said danger zone;

said transducers receiving echoes reflected from objects in a path of travel of said pulsed energy;

said transducers generating corresponding electrical signals; and

routing said signals to said circuit for analog to digital conversion.

10. The method of claim 6 wherein said second data set is obtained by the steps of:

sending a signal from said microsequencer to said transducer;

said transducer emitting 16 cycles of pulsed energy towards said danger zone;

said transducers receiving echoes reflected from objects in a path of travel of said pulsed energy;

said transducers generating corresponding electrical signals;

routing said signals to said circuit for analog and digital conversion; and

repeating the steps until a stop signal is received.

11. The method of claim 6 wherein said comparing comprises the steps of:

establishing and updating said corresponding second data set as a weighted arithmetic alarm probability data set;

storing said weighted arithmetic probability data set;

using statistical analysis algorithms to enable said microsequencer to analyze and apportion a suitable increment or decrement rate to a set of temporary storage alarm probability registers before alarm activation;

comparing current accumulated alarm probability data with said reference image and;

setting an alarm condition if significant variations are detected.

7. A method of ultrasonic monitoring of a danger zone of a vehicle when stationary, using a system comprised of one or more transducers, circuit means for analog to digital conversion and a microsequencer programmed to control said transducers, said method comprising the steps of:

initiating an area scan to obtain and generate an initial digital reference data set representing a pattern of distances of objects present in said zone when said vehicle is stationary, by

a) sending a first signal from said microsequencer to said transducer, said transducer in response to said signal emitting a first burst of pulsed energy towards said danger zone;

b) after a first predetermined time t₁, receiving echoes reflected from an object in a path of travel of said pulsed energy;

c) said transducers generating corresponding electrical signals;

d) routing said signals to said circuit for analog to digital conversion;

e) after a second predetermined time t₂, receiving echoes reflected from a different object in a path of travel of said pulsed energy;

f) said transducers generating corresponding electrical signals; and

,

g) routing said signals to said circuit for analog to digital conversion;

storing said reference data set;

scanning said danger zone;

establishing and updating a corresponding second data set;

comparing said second data set with said reference data set before said vehicle moves; and

setting an alarm condition in dependence upon significant variations above a predetermined level between said second data set and said initial reference data set being detected.

13. An ultrasonic system for monitoring a danger zone of a vehicle, said system comprising:

transducer means for generating ultrasonic acoustic energy and for receiving reflected echoes;

circuit means for analog to digital signal conversion of acoustic echoes from said transducer means; and

a microsequencer programmed for controlling said transducer means, said microsequencer is programmed to, upon receiving a sequence of digitized acoustic echoes from said circuit means;

a) generate from said sequence of digitized acoustic echoes an initial reference data set relating to objects in said danger zone at the time said vehicle becomes stationary, wherein the initial data set is derived from signals reflected from a plurality objects at different distances from said transducer means;

(b) store said initial data set;

(c) generate a subsequent sequence of acoustic signals;

(d) monitor a subsequent sequence of digitized acoustic echoes of the acoustic signal;

(e) generate from said subsequent sequence of digitized acoustic echoes, a second data set wherein the second data set is derived from objects at a plurality of different locations, and,

(f) compare said second data set with said initial reference data set and,

(g) signal an alarm if a variation between said initial reference data set and said second data set is greater than a predetermined value.

15. A method of ultrasonic monitoring of a danger zone of a vehicle when stationary, using a system comprised of one or more transducers, circuit means for analog to digital conversion and a microsequencer programmed to control said transducers, said method comprising the steps of:

initiating an area scan to obtain and generate an initial digital reference data set representing a pattern of distances of objects present in said zone when said vehicle is stationary, said initatiating step including the steps of;

a) providing a plurality of times t_n, where n is an integer;

b) sending a first signal from said microsequencer to said transducer, said transducer in response to said signal emitting a first burst of pulsed energy towards said danger zone;

c) after a first predetermined time t₁, receiving echoes reflected from an object in a path of travel of said pulsed energy;

d) said transducers generating corresponding electrical signals;

e) routing said signals to said circuit for analog to digital conversion;

f) after an predetermined time t_n, receiving echoes reflected from a different object in a path of travel of said pulsed energy,

g) said transducers generating corresponding electrical signals;

h) routing said signals to said circuit for analog to digital conversion;

i) performing the steps of (e) to (g) for different values of n a predetermined number of times, each corresponding to a different value of n;

storing said reference data set;

scanning said danger zone;

establishing and updating a corresponding second data set;

comparing said second data set with said reference data set before said vehicle moves; and

setting an alarm condition in dependence upon significant variations above a predetermined level between said second data set and said initial reference data set being detected.

16. A method as defined in claim 15, where n is a value from 2 to 8.