Target detector with size detection and method thereof

• US 8,829,439 B2
• Filed: 10/16/2012
• Issued: 09/09/2014
• Est. Priority Date: 10/16/2012
• Status: Active Grant

• Current Assignee: The United States Government As Represented By The Secretary Of The Army
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Damarla, Thyagaraju
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Malkowski, Kenneth J
• Application Number:
  US13/652,570
• Publication Number:
  US 20140103212A1
• Time in Patent Office: 693 Days
• Field of Search: 250/338.3, 250/345
• US Class Current: 250/338.3
• CPC Class Codes: G08B 13/193 using focusing means

Abstract

A method and system for detecting targets comprising at least one first receiver for receiving radiation, the radiation comprises beams of radiation spaced horizontally; at least one second receiver for receiving radiation, the radiation comprises beams of radiation spaced horizontally and vertically such that the beams of radiation received by the second receiver travel through different predetermined heights from the horizontal plane; at least one processor for receiving data from the first and second receivers, the at least one receiver operating to locate a target passing in the vicinity of the first and second receivers and determine the height of the target based upon the recordation of certain of the beams at a predetermined heights relative to the horizontal plane and the width of a target based upon the horizontal spacing of the beams.

Claims

1. A system for detecting targets comprising:

at least one first receiver for receiving radiation emitted by a passing animal or human, the radiation received by the at least one first receiver comprising-beams of radiation spaced horizontally;

at least one second receiver for receiving radiation emitted by a passing animal or human, the radiation received by the at least one second receiver comprising beams of radiation spaced horizontally and vertically such that the beams of radiation received by the at least one second receiver travel at different predetermined heights relative to the horizontal plane, wherein the radiation is received by each of the at least one first and second receivers through a Fresnel array having a plurality of channels;

the Fresnel array of the at least one second receiver being inclined at an angle to the horizontal plane resulting in channels at different vertical and horizontal locations; and

at least one processor for receiving data from the at least one first and second receivers, the at least one processor operating to locate a target passing in the vicinity of the at least one first and second receivers and approximating the height and width of a target based upon radiation entering the plurality of channels at differing vertical and horizontal locations;

the height of the target being based upon the recordation of certain of the beams at a predetermined heights relative to the horizontal plane and the width of a target based upon the horizontal spacing of the beams.

2. The system of claim 1 wherein the beams of radiation entering the at least one first and second receivers through Fresnel arrays comprise positive and negative sub-beams, wherein based upon the polarity of the signal received by the at least one first and second receivers, the distance from the at least one first and second receivers to the target is determined.

3. The system of claim 1 wherein the at least one of the at least one first and second receivers comprises at least three receivers positioned at predetermined different heights relative to the ground.

4. A system for detecting targets comprising:

at least one first receiver for receiving infrared radiation, the infrared radiation received by the at least one first receiver comprising-beams of radiation spaced horizontally;

at least one second receiver for receiving infrared radiation, the infrared radiation received by the at least one second receiver comprising beams of radiation spaced horizontally and vertically such that the beams of radiation received by the at least one second receiver travel at different predetermined heights relative to the horizontal plane;

the at least one first and second receivers comprising first and second Fresnel lenses operatively associated with the at least one first and second receivers, the beams of radiation received by the Fresnel lenses being received into a plurality of channels within the at least one first and second receivers, the beams of radiation received into channels of the at least one second receiver originating at varying heights relative to the ground, such that as determined by the intersection of the beams with a plane perpendicular to the ground level and perpendicular to the direction of travel, the cross sections of the channels are at an angle in the range of approximately 5 to 30°

to the horizontal plane, so that based upon the detection of radiation within the channels, the height and width of the target may be determined; and

at least one processor for receiving data from the at least one first and second receivers, the at least one processor operating to locate a target passing in the vicinity of the at least one first and second receivers and determine the height of the target based upon the recordation of certain of the beams at a predetermined heights relative to the horizontal plane and the width of a target based upon the horizontal spacing of the beams.

5. A system for detecting targets comprising:

at least one first receiver for receiving radiation, the radiation received by the at least one first receiver comprising-beams of radiation spaced horizontally;

at least one second receiver for receiving radiation, the radiation received by the at least one second receiver comprising beams of radiation spaced horizontally and vertically such that the beams of radiation received by the at least one second receiver travel at different predetermined heights relative to the horizontal plane, wherein the at least one second receiver receives beams spread horizontally and vertically at different heights, such that as determined by the intersection of the beams with a plane perpendicular to the ground level and perpendicular to the direction of travel, the beams form an angle in the range of approximately 5 to 30°

to the horizontal plane; and

at least one processor for receiving data from the at least one first and second receivers, the at least one processor operating to locate a target passing in the vicinity of the at least one first and second receivers and determine the height of the target based upon the recordation of certain of the beams at a predetermined heights relative to the horizontal plane and the width of a target based upon the horizontal spacing of the beams.

6. The system of claim 5 wherein the beams of radiation received by the at least one first and second receivers comprise sub-beams having positive and negative polarity, the positive and negative polarity of the sub-beams resulting in voltages generated by the at least one first and second receivers that are proportional to the distance to the target and whereupon based on the voltages in conjunction with predetermined set of calibration values;

the distance to the target is estimated by the at least one processor and based upon data received from the at least one first and second receivers, the approximate height and width of the target is computed.

7. A system for detecting and discriminating targets comprising:

at least one first receiver for receiving infrared radiation above ground level spread in a horizontal and vertical direction;

at least one second receiver for receiving infrared radiation above ground level spread in a horizontal and vertical direction substantially at different heights than the at least one first receiver such that the radiation received by the at least one second receiver travels through a plane perpendicular to the ground level at heights differing from the radiation received by at least one first receiver;

the first and second receivers comprising first and second Fresnel lenses operatively associated with the at least one first and second receivers, radiation received by the Fresnel lens being received into a plurality of channels within the first and second receivers, the radiation received into channels of the second receiver originating at predetermined varying heights relative to the ground, such that as determined by the intersection of the beams with a plane perpendicular to the ground level and perpendicular to the direction of travel, the cross sections of the channels are at an angle in the range of approximately 5 to 30°

to the horizontal plane; and

at least one processor for receiving data from the at least one first and second receivers, the at least one processor operating to locate a target passing in the vicinity of the at least one first and second receivers, and based upon the detection of radiation within the channels, the height and width of the target may be determined, the height of the target being based upon the passage of the radiation at a calculated height relative to a perpendicular plane in which the target is determined to be located and the width of a target based upon the width of the passage of radiation relative to a perpendicular plane in which the target is determined to be located.

8. A system for detecting and discriminating targets comprising:

at least one first receiver for receiving radiation above ground level spread in a horizontal and vertical direction;

at least one second receiver for receiving radiation above ground level spread in a horizontal and vertical direction substantially at different heights than the at least one first receiver such that the radiation received by the at least one second receiver travels through a plane perpendicular to the ground level at heights differing from the radiation received by at least one first receiver such that, as determined by the intersection of the beams with a plane perpendicular to the ground level and perpendicular to the direction of travel, the different heights form an angle in the range of approximately 5 to 30°

to the horizontal plane; and

at least one processor for receiving data from the at least one first and second receivers, the at least one processor operating to locate a target passing in the vicinity of the at least one first and second receivers and determine the height of the target based upon the passage of the radiation at a calculated height relative to a perpendicular plane in which the target is determined to be located and the width of a target based upon the width of the passage of radiation relative to a perpendicular plane in which the target is determined to be located.

9. The system of claim 8 wherein each Fresnel array is positioned such that radiation entering each of at least one first and second receivers passes through the Fresnel arrays.

10. The system of claim 8 wherein data is inputted from the at least one first and second receivers into the at least one processor and based upon the inputted data the system determines whether the target is a human or an animal and wherein a direction of motion of the target is determined based upon whether whichever of the first and second receivers is positioned leftmost or rightmost and whether the first or second receiver generates a signal first.

11. The system of claim 8 wherein the at least one second receiver comprises a series of second receivers positioned at predetermined heights, and the system has the capability of determining height and width of targets, the system using the information obtained by the second receivers positioned at different heights for motor vehicle detection.

12. A system for detecting and discriminating targets comprising:

at least one first receiver for receiving radiation above ground level spread in a horizontal and vertical direction;

at least one second receiver for receiving radiation above ground level spread in a horizontal and vertical direction substantially at different heights than the at least one first receiver such that the radiation received by the at least one second receiver travels through a plane perpendicular to the ground level at heights differing from the radiation received by at least one first receiver;

each of the at least one first and second receivers being operatively associated with a Fresnel array such that one Fresnel array is positioned to receive radiation in the form of beam patterns substantially parallel to the horizontal plane and the other Fresnel array is positioned so as to receive radiation in the form of beam patterns at a angle, as determined by the intersection of the beams with a plane perpendicular to the ground level and perpendicular to the direction of travel, in the range of approximately 5°

to 30°

relative to the horizontal plane; and

at least one processor for receiving data from the at least one first and second receivers, the at least one processor operating to locate a target passing in the vicinity of the at least one first and second receivers and determine the height of the target based upon the passage of the radiation at a calculated height relative to a perpendicular plane in which the target is determined to be located and the width of a target based upon the width of the passage of radiation relative to a perpendicular plane in which the target is determined to be located.

13. The system of claim 12 wherein the radiation received by the at least one first and second receivers comprises a plurality of beams comprising sub-beams with positive and negative polarity, the positive and negative polarity of the sub-beams resulting in voltages generated by the at least one first and second receivers that are proportional to the distance to the target and whereupon based on the voltages in conjunction with predetermined set of calibration values, the range of the target is estimated by the at least one processor and based upon data received from the at least one first and second receivers, the approximate height and width of the target is computed.

14. A method of target detection comprising:

obtaining data from at least one upper and lower receivers;

at least one horizontally spaced upper or lower receiver adapted to receive a light beam that is spaced horizontally from the beam received by another of the at least one upper or lower receivers;

estimating the voltage difference between the at least one upper and lower receivers for each beam of radiation received using at least one processor operatively connected to and receiving signals from the at least one upper and lower receivers;

based on the voltage difference, estimating a range using a set of predetermined calibration values;

the range being short range if the distance is less than a predetermined distance and long range if equal to or greater than the predetermined distance;

determining a direction of motion of the target depending on which one of the horizontally spaced at least one lower receiver or at least one upper receiver generates the signal first;

such that if the at least one receiver that is adapted to receive a light beam further to the left generates a signal first, the target is moving from left to right; and

if the at least one receiver that is adapted to receive a light beam further to the right generates a signal first, the target is moving from right to left;

using the at least one processor, estimating the height of the target depending on the highest beam pattern of the upper receiver that is effected by the target;

estimating the range of the target by determining the number of beams the target occupies depending on how many times the slope of the signal to the processor is changed mid stream, in the case of a short range target and, if the range is long, determining the times t₁ and t₂ when a signal crosses an average of the amplitude of the signal for both the at least one upper and lower receivers, where t₁ represents when the time the target is initially detected and t₂ represents the time the signal peaks;

estimating the velocity v of the target based on the time difference between times t₁ and t₂ and the distance between the two beams using equation

15. The method of claim 14 wherein the predetermined distance is determined as an indicator to differentiate between short or long ranges based upon the Fresnel lens array and number of beam patterns.

16. A system for detecting and discriminating targets comprising:

at least one first receiver for receiving radiation above ground level spread in a horizontal and vertical direction;

at least one second receiver for receiving radiation above ground level spread in a horizontal and vertical direction substantially at different heights than the at least one first receiver such that the radiation received by the at least one second receiver travels through a plane perpendicular to the ground level at heights differing from the radiation received by at least one first receiver;

each of the at least one first and second receivers being operatively associated with a Fresnel array such that one Fresnel array is positioned to receive radiation in the form of beam patterns substantially parallel to the horizontal plane and the other Fresnel array is positioned at an angle to the horizontal plane so as to receive radiation in the form of beam patterns at a angle, as determined by the intersection of the beams with a plane perpendicular to the ground level and perpendicular to the direction of travel, in the range of approximately 5°

to 30°

relative to the horizontal plane; and

at least one processor for receiving data from the at least one first and second receivers, the at least one processor operating to locate a target passing in the vicinity of the at least one first and second receivers and determine the height of the target based upon the passage of the radiation at a calculated height relative to a perpendicular plane in which the target is determined to be located and the width of a target based upon the width of the passage of radiation relative to a perpendicular plane in which the target is determined to be located.