Passenger screening system and method

Abstract

A method and scanner configured to determine whether a person's feet are positioned at a predetermined location of a predetermined scanning area and configured to scan the feet to detect a presence of a metal, an explosive, or other type of target substance.

1 . A method, comprising:
 sensing when a person's feet are placed within a predetermined screening area of a scanner; and   verifying that the feet are at respective predetermined locations within the predetermined screening area.   
   
   
       2 . The method of  claim 1 , further comprising:
 scanning the feet with a magnetic field to detect a presence of metal.   
   
   
       3 . The method of  claim 2 , wherein the scanner is a metal detector. 
   
   
       4 . The method of  claim 1 , further comprising:
 scanning the feet using radio frequency spectroscopy to detect a target substance.   
   
   
       5 . The method of  claim 4 , wherein the scanner is a quadrupole resonance scanner. 
   
   
       6 . The method of  claim 4 , wherein the target substance is an explosive. 
   
   
       7 . The method of  claim 1 , further comprising:
 generating a distance profile of the feet when the feet are proximate a sensor array based on a signal output by the sensor array; and   utilizing the distance profile to determine at least one of:
 a length of a foot, 
 a distance from a foot to the sensor array, 
 a position of a foot along the sensor array, and 
 an angle of a foot with respect to the sensor array. 
   
   
   
       8 . The method of  claim 7 , wherein verifying that the feet are at respective predetermined locations within the predetermined screening area further comprises:
 utilizing the distance profile to calculate a region of the predetermined area that is covered by the foot; and   comparing the calculated region with a predetermined acceptable foot placement region.   
   
   
       9 . The method of  claim 1 , further comprising:
 outputting a prompt to reposition the feet, if the feet are determined not to be at the respective predetermined locations.   
   
   
       10 . The method of  claim 9  wherein the prompt is an audio indicator generated by a computer processor. 
   
   
       11 . The method of  claim 9 , wherein the prompt is a visual indicator generated by a computer processor. 
   
   
       13 . The method of  claim 1 , wherein the scanner further comprises an inductive sensor, the method further comprising:
 outputting a prompt to reposition the feet symmetrically over the inductive sensor, if the feet are determined not to be at the respective predetermined locations.   
   
   
       14 . The method of  claim 1 , wherein the scanner further comprises two metal detection coils, the method further comprising:
 outputting a prompt to reposition the feet symmetrically between the two metal detection coils, if the feet are determined not to be at the respective predetermined locations.   
   
   
       15 . The method of  claim 7 , wherein the sensor array is an infrared sensor array that comprises an infrared transmitter and an infrared transceiver. 
   
   
       16 . The method of  claim 1 , wherein the scanner further comprises a first camera and a second camera, the method further comprising:
 operating the first camera to generate a first image of the feet;   operating the second camera to generate a second image of the feet;   combining the first image and the second image; and   determining a position of the feet using the combined first image and the second image.   
   
   
       17 . The method of  claim 1 , wherein the scanner further comprises a pressure sensor, the method further comprising:
 outputting a prompt to reposition the feet to activate the pressure sensor, if the feet are determined not to be within the respective predetermined locations.   
   
   
       18 . The method of  claim 1 , wherein the scanner further comprises an ultrasonic ranging system having an ultrasonic transmitter and an ultrasonic receiver, the method further comprising:
 activating the ultrasonic transmitter to emit a plurality of pulsed electronic signals into at least a portion of the person;   activating the ultrasonic receiver to receive echoes from the person; and   processing the received echoes to determine whether the feet are positioned at the respective predetermined locations.   
   
   
       19 . The method of  claim 1 , wherein the scanner further comprises a laser ranging device having a light emitting device and a light receiving device, the method further comprising:
 activating the light emitting device to emit a light pulse for reflection from the person;   activating the light receiving device to receive the reflected light pulse;   measuring a round trip time interval of the light pulse; and   utilizing the measured round trip time interval to determine whether the feet are positioned at the respective predetermined locations.   
   
   
       20 . The method of  claim 1 , wherein verifying that the feet are positioned at respective predetermined locations further comprises:
 verifying that a first foot is positioned at a first predetermined location; and   verifying that a second foot is positioned at second predetermined location.   
   
   
       21 . A scanner, comprising:
 a metal detector having two metal detection coils that are spaced apart relative to each other;   an inductive sensor configured to detect a target substance;   a position sensor configured to sense when a person's feet are placed within a predetermined screening area of the scanner; and   a computer coupled with the metal detector, the inductive sensor, and the position sensor, the computer configured to:
 operate the metal detector to scan the feet for a presence of metal; 
 operate the inductive sensor to scan the feet for a presence of the target substance; and 
 operate the position sensor to verify that the feet are positioned at respective predetermined locations within the predetermined screening area. 
   
   
   
       22 . The scanner of  claim 22 , wherein the target substance is an explosive. 
   
   
       23 . The scanner of  claim 21 , wherein the computer is further configured to:
 output a prompt to reposition the feet symmetrically over the inductive sensor, if the feet are determined not to be positioned at the respective predetermined locations.   
   
   
       24 . The scanner of  claim 21 , wherein the computer is further configured to:
 output a prompt to reposition the feet symmetrically between the two metal detection coils, if the feet are determined not to be positioned at the respective predetermined locations.   
   
   
       25 . The scanner of  claim 21 , wherein the position sensor is an infrared sensor array having an infrared transmitter and having an infrared receiver positioned to receive an infrared signal emitted from the infrared transmitter. 
   
   
       26 . The scanner of  claim 21 , wherein the position sensor comprises:
 a first camera configured to generate a first image of the feet;   a second camera configured to generate a second image of the feet; and   wherein the computer is further configured to combine the first image and the second image and to determine from the combined image whether the feet are positioned at the respective predetermined locations.   
   
   
       27 . The scanner of  claim 26 , wherein the computer is further configured to:
 outputting a prompt to reposition the feet, if the feet are determined not to be positioned at the respective predetermined locations.   
   
   
       28 . The scanner of  claim 21 , wherein the position sensor is a pressure sensor configured to activate when depressed by at least one of the feet. 
   
   
       29 . The scanner of  claim 28 , wherein the computer is further configured to:
 output a prompt to reposition the feet to activate the pressure sensor, if the feet are determined not to be positioned at the respective predetermined locations.   
   
   
       30 . The scanner of  claim 21 , wherein the position sensor comprises:
 an ultrasonic transmitter; and   an ultrasonic receiver positioned and configured to receive an ultrasonic signal emitted by the ultrasonic transmitter.   
   
   
       31 . The scanner of  claim 30 , wherein the computer is further configured to:
 activate the ultrasonic transmitter to emit a plurality of pulsed ultrasonic signals into at least a portion of the person;   activate the ultrasonic receiver to receive echoes from the person; and   determine from the received echoes whether the feet are positioned at the respective predetermined locations.   
   
   
       32 . The system of  claim 21 , wherein the position sensor comprises a laser ranging device having a light emitting device and a light receiving device, wherein the computer is further configured to:
 activate the light emitting device to emit a light pulse for reflection from the person;   activate the light receiving device to receive the reflected light pulse;   measure a round trip time interval of the light pulse; and   utilize the measured round trip time interval to determine whether the feet are positioned at the respective predetermined locations.   
   
   
       33 . The method of  claim 21 , wherein the computer is further configured to operate the position sensor to:
 verify that a first foot is positioned at a first predetermined location; and   verify that a second foot is positioned at second predetermined location.