Device and method for adaptive ultrasound sensing

• US 7,130,244 B2
• Filed: 12/24/2003
• Issued: 10/31/2006
• Est. Priority Date: 12/27/2002
• Status: Active Grant

• Current Assignee: Eli Gal, Uri Agam
• Original Assignee: Eli Gal, Uri Agam
• Inventors: Gal, Eli, Agam, Uri
• Primary Examiner(s): Lobo, Ian J.
• Application Number:
  US10/744,047
• Publication Number:
  US 20040136270A1
• Time in Patent Office: 1,042 Days
• Field of Search: 367/98, 367/99, 367/909
• US Class Current: 367/98
• CPC Class Codes: E05F 15/73 responsive to movement or presence of persons or objects
• CPC Class Codes: E05F 2015/763 using acoustical sensors
• CPC Class Codes: G01S 15/04 Systems determining presence of a target
• CPC Class Codes: G01S 7/52004 Means for monitoring or calibrating short-range imaging G01S7/5205
• CPC Class Codes: Y10S 367/909 Collision avoidance

Abstract

The adaptive system and method for ultrasound sensing comprises re-evaluating over time the detection threshold for predetermined sensing positions along the scanning direction to cope for the static target and environment changes at the sensing positions. The method includes comparing the measured echo value at each sensing position to a reference echo value corresponding to the same sensing position, and to iteratively determine a new reference value whenever the echo value is greater than the reference echo value and that the difference between the measured echo value and the reference echo value is lower than a detection assurance factor. The use of the adaptive ultrasound sensing system and method allows locating the sensor at different location without requiring a new calibration thereof, since the sensor learns the clutter dynamically and the detection thresholds are being built accordingly without being dependent on the environment in which the sensor is located.

Claims

1. An adaptive ultrasound detecting method comprising:

emitting an ultrasound beam along a scanning direction and receiving an echo value e(i) from a number I of sensing positions p(i) along said scanning direction;

comparing each said echo value e(i) to a detection threshold dt(i) corresponding to said sensing position p(i);

whereby a detection occurs when said echo value e(i) is greater than said detection threshold dt(i);

the improvement wherein at least one of said detection thresholds dt(i) is revaluated over time to cope for environment changes at sensing position p(i) corresponding to said at least one of said detection thresholds dt(i), wherein at least one detection assurance factor is provided, at least one of said detection thresholds dt(i) being revaluated over time including;

a) emitting an ultrasound sensing beam along the scanning direction and receiving an echo value e(i) from said sensing position p(i) corresponding to said at least one of said detection thresholds dt(i);

b) comparing said echo value e(i) obtained at sensing position p(i) to a reference echo value r(i) corresponding to said sensing position p(i);

c) if said echo value e(i) is lower than or equal to said reference echo value r(i) then the method stops;

d) if said echo value e(i) is greater than said reference echo value r(i) then verifying whether a difference between said echo value e(i) and said reference echo value r(i) is greater than said detection safety factor;

e) if said difference between said echo value e(i) and said reference echo value r(i) is lower than said detection assurance factor then ee1) storing said echo value e(i) as said reference echo value r(i) for sensing position p(i), and, ee2) repeating steps a) to e); and

f) if said difference between said echo value e(i) and said reference echo value r(i) is greater than or equal to said detection safety factor then a detection occurs and the method stops.

2. A method as recited in claim 1, wherein said echo value e(i) and said reference echo value r(i) are in the form of voltage values.

3. A method as recited in claim 1, wherein all of said detection thresholds dt(i) are revaluated over time.

4. A method as recited in claim 1, wherein a plurality of assurance factors is provided;

one of said plurality of assurance factors corresponding to each said sensing position p(i).

5. The use of a method as recited in claim 1, in one of a door control apparatus for automatic doors, a proximity detection system for automation, a self check-out system, and robotics and machinery security devices.

6. A method for determining ultrasound detection thresholds along a scanning direction, the method comprising:

a) providing a reference echo r(i) for each of a number I of sensing position p(i) along a scanning direction;

b) providing at least one detection assurance factor;

for each sensing position p(i) along the scanning direction;

c) emitting an ultrasound sensing beam along the scanning direction and receiving an echo value e(i) from said sensing positions p(i);

d) comparing the echo value e(i) obtained at sensing position p(i) to said reference echo value r(i) corresponding to said sensing position p(i);

e) if said echo value e(i) is lower than or equal to said reference echo value r(i) then the method stops, a target detection threshold for sensing position p(i) being equal to the sum of the reference echo value r(i) and said at least one assurance factor;

f) if said echo value e(i) is greater than said reference echo value r(i) then verifying whether a difference between said echo value e(i) and said reference echo value r(i) is lower than said detection assurance factor;

g) if said difference between said echo value e(i) and said reference echo value r(i) is lower than said detection assurance factor then gg1) storing said echo value e(i) as said reference echo value r(i) for sensing position p(i) and, gg2) repeating steps c) to g); and

h) if said difference between said echo value e(i) and said reference echo value r(i) is greater than or equal to said detection assurance factor then a detection occurs and the method stops.

7. A method as recited in claim 6, wherein said sensing positions are equally distanced from one another.

8. A method as recited in claim 6, wherein said echo value e(i) and said reference echo value r(i) are in the form of voltage values.

9. A method as recited in claim 6, wherein a plurality of assurance factors are provided, one of said plurality of assurance factors corresponding to each said sensing position p(i).