SUNNERGREN, Per (Videgårdsvägen 51, Surte, S-445 57, SE)
HARALD, Kjell (Illervägen 6, Sävedalen, S-433 70, SE)
LARSSON, Sverker (Trumpetvägen 2, Mölnlycke, S-435 41, SE)
HAGLUND, Leif (Rängevägen 16, Brokind, S-590 45, SE)
KARLSSON, Gunnar (Malörtsvägen 17, Skövde, S-541 39, SE)
SUNNERGREN, Per (Videgårdsvägen 51, Surte, S-445 57, SE)
HARALD, Kjell (Illervägen 6, Sävedalen, S-433 70, SE)
LARSSON, Sverker (Trumpetvägen 2, Mölnlycke, S-435 41, SE)
HAGLUND, Leif (Rängevägen 16, Brokind, S-590 45, SE)
| CLAIMS 1 . A system for Concurrent Multi-Person Security Screening CMPSS, arranged for security screening of persons passing a detection area (105), the screening being arranged to be performed by means of at least a cloth penetrating type of sensor (111 , 402) or sensors, said sensor type or sensor types arranged for producing sensor information to a processing arrangement (401 ), the processing arrangement comprising algorithms for threat analysis arranged to use the sensor information as input data and to produce o utpu t i nform atio n to o pe rator panels (409, 410), c h a r a c t e r i z e d in that : • said sensors (109-111 , 303, 402-406) are arranged to be positioned at defined positions within the detection area and to have a defined working area, whereas the positions and working area for each sensor are arranged to be stored in the processing arrangement (401 ), • the CMPSS comprises a person tracking subsystem arranged to assign an identification number to each person passing the detection area and to continuously and automatically track each person during the passage through the detection area and to define the position of each person within the detection area (105) at all times, whereas the positions are arranged to be transferred to the processing arrangement (401 ), and • the working area of each sensor and the position of persons are arranged to be continuously compared in an association subsystem and when a person or persons is/are within the working area of one or several sensors, sensor information at that time is arranged to be associated to the person or the persons being within the working area and • when the sensor information associated to a certain person or persons meets predetermined criteria, stored in the processing arrangement (401), an alert is arranged to be generated and presented at the operator panels (409, 410). 2. A system according to claim 1, characterized in that the person tracking subsystem is a video tracking system. 3. A system according to claim 2, characterized in that the video tracking system comprises a number of image registration means (112, 408) arranged to repeatedly record data pertaining to multiple simultaneous representations of events occurring within the area and wherein at least one of the image registration means (112, 408) are arranged to repeatedly record image data based upon which a data processing unit repeatedly is arranged to determine a respective position for each of the objects. 4. A system according to claim 1, characterized in that the person tracking subsystem is an RFID system (407). 5. A system according to claim 4, characterized in that multiple sensors are arranged at fixed locations in order to accurately measure the position of RFID tags within the detection area (105) in three dimensions, the measurements from all sensors being arranged to be collected to a processing device for calculating positional tracking data for the objects to which the RFID tags are attached. 6. A system according to any one of claims 1-5, characterized in that when sensor information is associated to more than one person this ambiguity is resolved by sensor fusion or by manual means. 7. A system according to any one of claims 1-6, characterized in that the detection area (105) is arranged in one separate lane or several separate lanes (201 , 202, 203) each lane having a width arranged to allow one person abreast passing the detection area walking. 8. A system according to any one of claims 1-6, characterized in that the detection area (105) is arranged over a wide, moving conveyor belt arranged to allow persons under scrutiny to pass the detection area walking, still-standing or still-sitting on the wide, moving conveyor belt, the speed of the wide moving conveyor belt being arranged to be variable in the direction of the flow through the CMPSS. 9. A system according to any one of claims 1-6, characterized in that the detection area (105) is arranged over one moving conveyor belt or at least two parallel moving conveyor belts, each conveyor belt corresponding to a lane (201, 202, 203) having a width allowing one person abreast, and persons under scrutiny to pass the detection area walking, still-standing or still-sitting on said conveyor belts, each conveyor belt may be arranged to move independently of each other and the speed of the conveyor belts being arranged to be variable in the direction of the flow through the CMPSS. 10. A system according to any one of claims 1-9, characterized in that luggage tracking is included in the system and being arranged so that the system keeps track of which person each piece of hand luggage belongs to by assigning the person and the piece or pieces of luggage belonging to that person one identification number each and keeping these identification numbers linked to each other. 11. A system according to claim 10, characterized in that the tracking of the luggage is performed by video cameras (112), RFID equipment (407) or position detectors or a combination of these three alternatives. 12. A system according to any one of claims 1-11, characterized in that image processing is included in the CMPSS , the image processing being arranged to allow the creation of one or several of the following features : • an image, compiled of images of the same person from several cloth penetrating sensors (111, 402) in different directions, including in the image also indications from other, non-imaging sensors, such as a sniffer (109, 403), for the same person, based on information received from other subsystems, • images compiled of images from cloth penetrating sensors (111, 402), overlaid on images from video cameras (112), • automatic image recognition to support the operators of the screening system to detect prohibited objects, • compilation of a 3D image using images from cloth penetrating sensors (111, 402) having different field of view and • compilation of a 3D image using several images from the same cloth penetrating sensor (111, 402) using different focal planes. 13. A system according to any one of claims 1-12, characterized in that the system is arranged such that every person may be subject to screening by several sensors concurrently, the sensors being designed to detect visible and concealed objects that could cause harm to people and property, the objects being manufactured by a wide range of materials and substances. 14. A system according to any one of claims 1-13, characterized in that luggage may be arranged to be screened by equipment located outside the detection area or the hand luggage may be arranged to be carried through the detection area and examined together with the carrier. 15. A system according to any one of claims 1-14, characterized in that the association subsystem is included in the CMPSS, the association subsystem being arranged to associate sensor measurements with information of extracted objects and substances from screening of persons and luggage to the appropriate person and luggage using information from the person tracking subsystem and the luggage tracking subsystem. 16. A system according to any one of claims 1-15, c h a r a ct e r i z ed in that an information fusion subsystem is included in the CMPSS, arranged to be used to support the process to make an automatic or manual threat evaluation for each person being screened by arranging for fusion of information from several sensors of same or different types in order to make information more reliable. 17. A system according to any one of claims 1-16, characterized in that system properties that are adjustable, as sensitivity levels of sensors and parameters in software modules, can be arranged to be modified in adaption to the present operational situation or information from external systems. 18. A system according to any one of claims 1-17, characterized in that sensors used in the CMPSS are arranged to be integrated in the structure of the building where the CMPSS is installed. 19. A system according to any one of claims 1-17, characterized in that the system is arranged to be designed for stationary installation or mobile deployment. 20. A system according to claim 1, characterized in that a combination of a video tracking system and an RFID system is arranged to be used for tracking of persons and/or luggage. 21. A system according to any one of claims 1 -20, characterized in that information from an examined group of persons is arranged to be evaluated to see if there is a pattern in the examined group that can become a threat, even if the detected information from each individual person does not present a threat. 22. A method for Concurrent Multi-Person Security Screening CMPSS, for security screening of persons passing a detection area (105), the screening is performed by means of at least a cloth penetrating type of sensor (111 , 402) or sensors, said sensor type or sensor types produces sensor information to a processing arrangement (401 ), the processing arrangement comprising algorithms for threat analysis using the sensor information as input data and producing output information to operator panels (409, 410), c h a r a c t e r i z e d in that : • said sensors (109-111 , 303, 402-406) are positioned at defined positions within the detection area (105) and having a defined working area, whereas the positions and working area for each sensor being stored in the processing arrangement, • the CMPSS comprises a person tracking subsystem to assign an identification number to each person passing the detection area and continuously and automatically track each person during the passage through the detection area (105) and to define the position of each person within the detection area at all times, whereas the positions are transferred to the processing arrangement (401 ), and • the working area of each sensor and the position of persons are continuously compared in an association subsystem and when a person or persons is/are within the working area of one or several sensors, sensor information at that time is associated to the person or the persons being within the working area and • when the sensor information associated to a certain person or persons meets predetermined criteria, stored in the processing arrangement, (401 ) an alert will be generated and presented at the operator panels (409, 410). |
TECHNICAL FIELD
The present invention relates to the field of systems and methods for security screening of people.
BACKGROUND ART
Due to the enhanced threat levels experienced at public places during the last decades, initiated already in the 1980's with the Lockerbie disaster, there is an increased demand for security screening in several parts of the society. This widened scope concerns both threat substances (not only explosives) and protection domains (not only air transport).
Today, person security screening is performed at certain strategic areas where air transportation is the best known example. An increasing need is also recognized in a much broader scope of applications, e.g. general mass transportation, public events, political convents and summits, high-value symbolic buildings and facilities and national borders.
The security screening systems of today have some major drawbacks which have to be remedied in order to be able to meet the widened threat scope in an acceptable way. The most important problems to be solved are:
• the intrusion in citizens' privacy due to inspections that causes discomfort to the innocent
• the low throughput capacity which results in frustrating queues and waiting time
• the involvement of a substantial amount of personnel
• the limited capabilities regarding the spectrum of threats • low performance regarding detection probability and false alarm rate. CA 2308747 shows an integrated walk-through personnel scanner system for security portals. When a person passes a portal and a proximity sensor, a signal is generated to start the detection and analysis processes of the various detectors in the integrated walk-through scanner system. There are at least two different kinds of detectors in the system as e.g. metal detectors, vapour analysers and passive millimetre wave cameras. A main drawback with this solution is that the system does not allow several persons to simultaneously, walk through the scanner system while they are concurrently scanned by different kinds of detectors. This has the consequence that the throughput becomes limited, leading to annoying queuing.
There is thus a need to solve these problems by introducing a fully integrated multi-sensor and evaluation system that enables continuous and high- capacity non-intrusive, concurrent security screening of several persons.
SUMMARY
The object of the invention is to reduce at least some of the mentioned deficiencies with prior art solutions and to provide:
• a system for Concurrent Multi-Person Security Screening
• a method for Concurrent Multi-Person Security Screening
to solve the problem to achieve a fully integrated multi-sensor and evaluation system that enables continuous and high-capacity, non-intrusive, concurrent security screening of several persons.
The object is achieved by providing a system for Concurrent Multi-Person Security Screening CMPSS, arranged for security screening of persons passing a detection area. The screening is arranged to be performed by means of at least a cloth penetrating type of sensor or sensors. Said sensor type or sensor types is/are are arranged for producing sensor information to a processing arrangement. The processing arrangement comprises algorithms for threat analysis arranged to use the sensor information as input data and to produce output information to operator panels (409, 410) wherein:
• said sensors are arranged to be positioned at defined positions within the detection area and to have a defined working area, whereas the positions and working area for each sensor are arranged to be stored in the processing arrangement,
• the CMPSS comprises a person tracking subsystem arranged to assign an identification number to each person passing the detection area and to continuously and automatically track each person during the passage through the detection area and to define the position of each person within the detection area at all times, whereas the positions are arranged to be transferred to the processing arrangement, and • the working area of each sensor and the position of persons are arranged to be continuously compared in an association subsystem and when a person or persons is/are within the working area of one or several sensors, sensor information at that time is arranged to be associated to the person or the persons being within the working area and
• when the sensor information associated to a certain person or persons meets predetermined criteria, stored in the processing arrangement, an alert is arranged to be generated and presented at the operator panels.
The object is further achieved by providing a method for Concurrent Multi- Person Security Screening CMPSS, for security screening of persons passing a detection area. The screening is performed by means of at least a cloth penetrating type of sensor or sensors. Said sensor type or sensor types produces sensor information to a processing arrangement. The processing arrangement comprises algorithms for threat analysis using the sensor information as input data and producing output information to operator panels wherein:
• said sensors are positioned at defined positions within the detection area and having a defined working area, whereas the positions and working area for each sensor being stored in the processing arrangement,
• the CMPSS comprises a person tracking subsystem to assign an identification number to each person passing the detection area and continuously and automatically track each person during the passage through the detection area and to define the position of each person within the detection area at all times, whereas the positions are transferred to the processing arrangement, and
• the working area of each sensor and the position of persons are continuously compared in an association subsystem and when a person or persons is/are within the working area of one or several sensors, sensor information at that time is associated to the person or the persons being within the working area and
• when the sensor information associated to a certain person or persons meets predetermined criteria, stored in the processing arrangement, an alert will be generated and presented at the operator panels.
By the invention hereby suggested, several persons are concurrently subject to a security check during passing a detection area. This will result in a possibility to increase the flow of people. The experience of privacy intrusion felt by the persons under scrutiny will diminish, and their experience of comfort and ease will improve. Furthermore, the time spent in queues, and the number of security officers relative to the number of people being checked, may be decreased. Additional advantages are achieved by implementing one or several of the features of the dependent claims which will be explained below.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 schematically shows an example of a system layout of the invention allowing free walking through a detection area.
Figure 2 schematically shows an example of a system layout of the invention using lanes.
Figure 3 schematically shows some optional features of the invention.
Figure 4 schematically shows one example of a block diagram of the invention.
DETAILED DESCRIPTION
The invention will now be described in detail with reference to the drawings.
The invention provides a system capable of concurrent security screening of several persons with respect to a wide range of forbidden objects and substances, including concealed items. The system contains several types of sensors whose outputs are brought together to form a basis for the security clearance decision. The term concurrent security screening means that the system's sensors at each point in time are able to examine several persons within the common detection area.
The Concurrent Multi-Person Security Screening (CMPSS) system is arranged for security screening of persons passing a detection area and may comprise several different types of sensors whose output data are fused and evaluated. The compiled information is continuously presented to an operator. A standard configuration of the CMPSS comprises: • at least a cloth-penetrating type of sensor or sensors arranged for detection of hidden objects such as weapons and explosives, and
• at least a person tracking subsystem and a subsystem arranged for association of sensor measurements with an appropriate person.
The cloth-penetrating type of sensor or sensors being arranged for producing sensor information to a processing arrangement. Many other types of sensors can also be used as will be explained. The processing arrangement comprises algorithms for threat analysis arranged to use the sensor information as input data and to produce output information to operator panels. Said sensors are arranged to be positioned at defined positions within the detection area and to have a defined working area, whereas the positions and working area for each sensor are arranged to be stored in the processing arrangement.
Additional sensors and functions can also be added as will be explained.
The system can optionally be equipped with additional sensors for detection of Chemical, Biological, Radiological, Nuclear and Explosive (CBRNE) substances. The invention is not restricted to certain sensors, but any suitable sensor for detection of substances and objects may be used.
The choice of sensor types enables the discovery of additional types of threat objects and substances. Sensor fusion makes it possible to minimise the rate of false alarm, as will be described.
The invention can be realized in four alternative, main configurations:
1. In the first configuration persons under scrutiny will be allowed to walk freely through a detection area. 2. Persons under scrutiny will in this second configuration be guided into lanes where the detection area is arranged in one separate lane or several separate lanes, each lane having a width arranged to allow one person abreast passing the detection area walking. This division into lanes may be obtained by painted lines, fences, glass panels or by some other means. The entry to each lane can be controlled by gates.
3. In this third configuration the detection area is arranged over a wide, moving conveyor belt arranged to allow persons under scrutiny to pass the detection area, walking, still-standing or still-sitting on the wide, moving conveyor belt. The conveyor belt may move with variable speed in the direction of the flow through the system. For example, by moving the conveyor belt at a lower speed, the operators will get more time to check each person. The speed of the conveyer belt can be adjustable in order to adapt to the operational conditions or to enhance measurement performance. The system may be integrated within existing conveyor belts used for person transportation.
4. In this fourth configuration the detection area is arranged over one moving conveyor belt or at least two parallel moving conveyor belts allowing persons under scrutiny to pass the detection area walking, still-standing or still-sitting on said conveyor belts. Each conveyor belt corresponds to a lane and thus allows one person abreast. Each conveyor belt may move, independently of each other, with variable speed, in the direction of the flow through the system. For example, by moving a conveyor belt at a lower speed, the operators will get more time to check each person. The speed of the conveyer belt can be adjustable in order to adapt to the operational conditions or to enhance measurement performance. The system may be integrated within existing conveyor belts used for person transportation. All configurations will result in a possibility to increase the flow of people. The experience of privacy intrusion felt by the persons under scrutiny will diminish, and their experience of comfort and ease will improve. Furthermore, the time spent in queues, and the number of security officers relative to the number of people being checked, may be decreased.
Referring to figure 1 , which is an example of how a CMPSS system 101 can be configured in a first configuration, the screening process takes place in the following way. Persons to be security screened pass the system from the left to the right in the example of figure 1. In the normal state of operation several persons under continuous movement are within the system. At the same time as persons are leaving the system, other persons may enter. The persons are allowed to walk freely at normal pace through a detection area 105. The set of sensors used in the system can be adapted to the actual need in the application and figure 1 shows one particular example. In a first (left) section 106 of the detection area 105, checking with sniffer sensors 109 is performed, searching for traces of explosives, chemicals or biological agents or combinations of these agents. Here shoe screening can also be performed simultaneously with co-located shoe screening X-rays sensors 1 10. In a second section 107 of the detection area 105, persons are screened with cloth penetrating sensors 111 in order to detect any concealed items. Additional sensors, searching for other objects and substances could in this example be placed in a third section 108 of the detection area. The three sections are normally arranged in a consecutive order, the first, second and third section, the first section being located at the entrance to the detection area. Other orders of the sections are also feasible within the scope of the invention.
Image registration means for tracking, in this example of the invention realized with video cameras 112, are used for the person tracking subsystem to survey the detection area 105 and associate the sensor measurements and images to the right person. Each video camera symbol in the example of figure 1 represents a pair of video cameras working according to the stereo camera principle which will be explained in association with the description of person tracking.
Referring now to figure 2, which is an example of how the CMPSS system 101 can be configured in the second configuration. The solution showed in figure 2 is configured for 3 persons walking abreast, each person in a separate lane, 201-203. The number of lanes and thus the number of persons walking abreast can be varied from one lane to several lanes depending on the width of the available detection area. In other respects the second configuration corresponds to the first configuration.
Configuration 3 corresponds to configurations 1 and configuration 4 corresponds to configuration 2 with the addition of a common conveyor belt for configuration 3 and one conveyor belt or parallel conveyor belts for configuration 4 as described above.
Some optional features of the invention are shown in figure 3:
• entry to the system may be controlled by parallel gates 301 , in order to regulate the admission of persons and • hand luggage may be left prior to sensor passage on a luggage track
302 with X-ray checking 303 (plus optional sniffer) and fetched after passing the detection area 105. • visitation facilities 304 located in a visitation area 305, and used in case of an alert from the CMPSS. At the visitation area person and luggage will be manually checked in case of an alert from the CMPSS.
It could be a manual pat down of a suspected person or persons or some further investigation using different types of sensors. The visitation area 305 can be located in direct connection with the detection area as illustrated in figure 3 or it can be located at suitable premises in the vicinity of the detection area.
Outdoor clothes, if any, are normally to be kept on. In certain cases, outdoor clothes may have to be removed and checked together with the hand luggage.
Persons that present a suspect or uncertain sensor result, or cannot be resolved from each other, e.g. parents with small children, or several persons being within the working area of a certain sensor at time of detection, will be diverged in the visitation area 305 for further checking, by manual or automated means, such as ordinary pat down. Such a certain sensor type is not able to pin-point the exact position of detection, but can only define a detection area, within which one or several persons can be located at the same time. An example of such a sensor is a sniffer, which detects traces of explosives in captured samples of surrounding air.
The outputs from the sensors are combined and the resulting, aggregated information is continuously evaluated for each examined person. The security clearance decision is based on this aggregated information for each person. During the security check the system automatically associates sensor measurements to the correct persons and tracks each individual through the system in order to facilitate, either, security clearance, further investigations or other measures. The system checks the occurrence of objects and substances present, on and with in cloth ing and on the bod ies of the examined persons. The system can be combined with hand luggage security checking using the luggage tracks 302.
Sensor information is processed by means of a processing arrangement. The processing arrangement can e.g. be distributed geographically to several computers or centralized to a Central Unit. Henceforth in the description the invention is exemplified with a processing arrangement comprising a Central Unit. In many cases, certain processing steps may preferably be performed within subsystems. This allocation will depend on the capabilities of different subsystems that are utilized in a specific realization of the system. The person tracking subsystem can e.g. in one realization of the invention be used for association processing. However any other suitable processing arrangement is within the scope of the invention.
A block diagram of one example of the invention is shown in figure 4. Sensor information is fed to a Central Unit, CU, 401. The CMPSS system is at least equipped with cloth penetrating sensors 402, typically comprising millimetre wave/THz cameras. Optional sensors, shown with dotted lines, are sniffers
403, shoe screening sensors 404 and additional sensors 405. The additional sensors can e.g. comprise neutron detectors for detection of radiological and nuclear threats. The different sensor types and technologies are further described below. Information from optional luggage sensors 406 are also fed to the Central Unit.
Tracking video cameras 408 is one example of sensors providing input to the person tracking subsystem included in the Central Unit.
Information from external systems 411 is also optionally fed to the Central Unit. Examples of external systems are ticketing systems, adjacent surveillance systems, intelligence information databases and identification systems.
Luggage and persons under scrutiny may also be tracked by RFID (Radio Frequency IDentification) 407 through the CMPSS. This will be further explained in association with the person tracking subsystem.
The collected information from sensors, cameras and RFID is processed in the Central Unit which provides an output to one or several local operator panels, Local OP, 409. One or several remotely located operator panels 410, Remote OP, can also be used in addition to or instead of the Local OP panels. These Remote OPs can be located at e.g. a regional centre, connected to the CMPSS via a communication link. The operator panels can in one example of the invention comprise one or several computer terminals in combination with one or several screens, displaying information from the image registration means. Information from the cloth penetrating sensors may be displayed on the terminals or screens as whole-body images of the person being scanned, with some modifications to protect the privacy of the person. An example of such protection is that the see-through sensor image can be overlaid on images from video cameras, which makes it easier for an operator to recognize the person and also hides details of the person's body. Automatically detected and classified objects can then be emphasized in the image and e.g. be framed in red or green boxes, with potential threat objects being within red boxes.
The CU can be divided into following subsystems:
• person tracking by cameras and/or RFID, • luggage tracking by cameras and/or RFID,
• image processing,
• screening of persons,
• screening of hand luggage,
• association and • information fusion.
The person tracking subsystem determines the position of all persons in the system and follows each person's path through the system. The luggage tracking subsystem tracks luggage through the CMPSS in a similar way as the person tracking subsystem. The tracking of persons and luggage is essential for the CU's ability to associate measurements and images from different sensors to the right person or luggage (or persons if the particular sensor has a large measuring area, also called working area). The image processing subsystem of th e C U ta kes as in put, images from cloth penetrating sensors and extracts potentially dangerous or prohibited objects from the images. In the screening of persons and hand luggage, sensors are used to detect CBRNE substances and prohibited objects. In the association subsystem the extracted objects and substances are associated to the appropriate person or luggage using information from the person tracking subsystem and the luggage tracking subsystem. Finally the information fusion and threat evaluation subsystem assembles all available information associated to each person and luggage, i.e. sensor measurements, information extracted by image processing and input from hand luggage screening as well as input from external systems, in order to make a threat assessment for each person. Optionally also information from an examined group of persons can be arranged to be evaluated to see if there is a pattern in the examined group that can become a threat, even if the detected information from each individual person does not present a threat. Normally a recently examined group of persons is chosen for this evaluation. An example can be when each person in a group brings unidentified objects that could be mounted together, to form a weapon or a destructive tool. Different threat evaluations for the same measurement results can also be made depending on the general threat level at the time of measurement. This information can be received from external systems.
Person tracking
The system includes a person tracking subsystem which follows the persons passing through the system. The tracking system used in the person tracking subsystem can e.g. be based on video tracking techn iques or RFI D- techniques, i.e. the person tracking subsystem can be a video tracking system or an RFID system or further, a combination of video tracking system and RFID system. The main tasks for the person tracking subsystem are to keep track of persons during their passage through the system, to determine the position of each person in the detection area and to enable sensor detections to be associated to the correct person.
The person tracking subsystem will be arranged to: • assign an identification number to each person passing the detection area and
• continuously and automatically track each person during the passage through the detection area and to define the position of each person within the detection area at all times, whereas the positions are arranged to be transferred to the processing arrangement, and
• detect when the person is within a predefined working area of each sensor
• provide an image (or images) of each person for recognition by the operators • collect face image(s) to be used for facial recognition both as a feature in the tracking and to be able to do data base search to find frequent flyers as well as suspected individuals
These detections will be sent to the information fusion and threat evaluation subsystem, which will associate the sensor measurements with the right person based on this coincidence in time and space. In case the tracking data originate from video images, a position of each person can be calculated either according to a single camera principle using the person's foot position in the image vs. the known geometry of the room or according to a stereo camera principle by stereo comparison of images. The field of view of cloth penetrating sensors normally covers several persons. The tracking position will be used to calculate the location of each person in the image of the cloth penetrating sensors, so that each object that is detected in the image can be associated with the right person. In case the tracking data originate from an RFID system, the position of each person will be obtained by techniques based on interferometry, propagation time etc. inherent in such a system.
Examples of technical systems that can be used as a base for person tracking are the video based system TRACAB Image Tracking System™, Sweden, and the RFID based system Ubisense Series 7000 system, UK. These systems are arranged to assign an identification number to each person and automatically track each person simultaneously during the passage through the detection area and to define the position of each person within the detection area at all times. The position is transferred to the processing arrangement. These systems are examples of suitable systems to be used for person tracking. Further developments or modifications of these systems or similar systems can also be used provided they can be arranged to assign an identification number to each person and automatically track each person simultaneously during the passage through the detection area and to define the position of each person within the detection area at all times. The position can be defined either as a two dimensional or three dimensional position. Normally the position is defined as a point on a plane constituting the floor of the detection area.
The Tracab system relates to image-based movement tracking of a number of objects in a particular area. A number of image registration means repeatedly records data pertaining to multiple simultaneous representations of events occurring within the area. Specifically, at least one stereo-pair of image registration means repeatedly record stereo-image data according to the stereo camera principle, based upon which a data processing unit repeatedly determines a respective position for each of the objects. Part of the Tracab system using the stereo camera principle is further described in patent application WO 2006/051049.
In one example of the invention a video tracking system is used where the position of each person is calculated according to the single camera principle, the result is in further processing compatible with the stereo camera principle.
In the general case the video tracking system comprises a number of image registration means arranged to repeatedly record data pertaining to multiple simultaneous representations of events occurring within the area and wherein at least one of the image registration means are arranged to repeatedly record image data according to the single camera or stereo camera principle, based upon which a data processing unit repeatedly is arranged to determine a respective position for each of the objects.
The Ubisense system uses multiple sensors at fixed locations in order to accurately measure the position of RFID tags within the detection area in three dimensions. Measurements from all sensors are collected to a processing device which calculates positional tracking data for the objects (persons) to which the RFID tags are attached.
The position data that is produced by the person tracking subsystem, for each person within the CMPSS, can also be used to:
• Cocalibrate all involved sensors, e.g. adjust sensor measuring properties, like direction and range: Here, the person tracking subsystem will detect when a person is within the predefined working area of a certain sensor and then send position data for that person to that sensor for its adjustment.
• Correlate and assemble images from several cloth penetrating sensors: Here, the person tracking subsystem will detect when a person is within a common area for several cloth penetrating sensors, and signal to the fusion subsystem, which will treat the images for that person as belonging together. The tracking position of each person will be used to calculate the position of each person in each sensor image, so that the fusion subsystem can associate the images for each person, and so that the images e.g. can be shown beside each other on the operator's displays.
• Correlate and assemble images and other outputs from several sensors. Here, the person tracking subsystem will detect when a person is within a common area for several sensors, and signal to the fusion subsystem, which will treat the sensor results for that person as belonging together.
• Check that persons do not tamper with the system, e.g. by moving in certain ways. Here, the output position data from the person tracking subsystem may be fed to a Behaviour Detector software, which by predetermined or pre-trained criteria can detect if a person moves in an abnormal way, and signal this either directly to a security officer, or to the information fusion subsystem for subsequent threat assessment. • Analyze, and automatically detect, obstruction of sensor operations due to unfavourable positioning of the persons within the screening area. Here, the person tracking subsystem will detect if a person will obstruct another person from a sensor, based on predefined rules relating to the working area of a certain sensor.
Tracking of persons under scrutiny and association of sensor measurements to the correct person can, in addition to be fully automatic, also be made manually or semi-automatically.
Persons and/or luggage under scrutiny may optionally be tracked by the RFID (Radio Frequency IDentification) 407 through the CMPSS. In this case a temporary RFID label is attached to the object in question, such that this label can be detected and its position be determined by fixed radio transceivers in the detection area. Temporary, in this context, means that the label may be discarded when leaving the CMPSS. The label may be either active, thus emit radio waves, or passive, thus reflect radio waves. The RFID tracking may be arranged to be used either in combination with or in lieu of the video tracking for tracking of persons and/or luggage. In one example of the invention video tracking can be used for person tracking and RFID for luggage tracking.
Luggage tracking
Tracking of hand luggage may be included in the system, arranged so that the system keeps track of which person each piece of hand luggage belongs to. In this case, the person tracking subsystem will detect when a piece of luggage is separated from a person and subsequently track both the person and the piece of luggage. The person and the piece or pieces of luggage belonging to that person will be assigned one identification number each by the person tracking subsystem or the luggage tracking subsystem and these identification numbers will be linked to each other. The person tracking subsystem can then detect when a track of a piece of luggage merges with a track of a person, i.e. when two linked identification numbers are in the same position again. This information will be sent to the information fusion and threat evaluation subsystem to decide whether the right person has taken the luggage or not. If not, an alarm will be generated. The luggage tracking may be performed in three different ways; by video cameras (similar to person tracking, see above), RFID equipment (see person tracking above) or by position detectors. In the latter case, detectors will signal when the piece of luggage reach certain positions along its transport path. Combinations of those three methods are possible, for example the luggage may be tracked by video cameras, except when it is not visible. Thus its entrance to and exit from a luggage X-ray machine may be detected by contact switches.
Image processing
Image processing may be applied in order to support the operators. The image processing being arranged to allow the creation of one or several of the following features: • an image, compiled of images of the same person from several cloth penetrating sensors in different directions, including in the image also indications from other, non-imaging sensors, such as a sniffer, for the same person, based on information received from other subsystems such as the person tracking, association and information fusion subsystems,
• images compiled of images from cloth penetrating sensors, overlaid on images from video cameras. This function makes it easier for an operator to recognize the person being scanned and also hides details of the scanned person's body,
• automatic image recognition to support the operators of the screening system to detect prohibited objects. Indication of prohibited and allowed objects can for example be arranged by framing in red and green boxes, • compilation of 3D image using images from cloth penetrating sensors having different field of view and
• compilation of 3D image using several images from the same cloth penetrating sensor using different focal planes.
Screening of persons
The system is arranged such that every person may be subject to screening by several sensors concurrently.
The system can be equipped with sensors designed to detect visible and concealed firearms and other weapons, knives and other sharp objects, hand grenades, explosives, containers and bottles, tools and other objects that could cause harm to people and property. The sensors of the system may be capable to detect threat objects of a wide range of materials and substances, e.g. metals, ceramics, plastics, liquids, leather, wood, narcotics.
The system can also be equipped with additional sensors designed to detect:
• gases and particles of explosives, chemical- and biological substances,
• radioactive and nuclear substances or weapons,
• object and substances in the examined persons' shoes, • object and substances within the examined person's body.
The sensors of the system can, in addition to being fixedly installed, also be movable in all three space dimensions to increase the measuring flexibility and performance.
Screening of hand luggage
Hand luggage may be arranged to be screened by equipment such as equipment for X-ray checking 303. This screening equipment is normally located within the detection area 105, as illustrated in figure 3, but can also be located outside the detection area 105. When appropriate sensors are available, the hand luggage may be arranged to be carried through the detection area and examined together with the carrier.
Association In the association subsystem sensor measurements with information of the extracted objects and substances from screening of persons and luggage are associated to the appropriate person and luggage using information from the person tracking subsystem and the luggage tracking subsystem.
The working area of each sensor and the position of persons and/or luggage is arranged to be continuously compared in the association subsystem and when a person/luggage or persons/luggage is/are within the working area of one or several sensors, sensor information at that time is arranged to be associated to the person/luggage or the persons/luggage being within the working area.
Results from hand luggage screening may be associated with the evaluation of person screening information to form a combined decision basis. This can be accomplished by using video tracking, RFID-tags on luggage or by other means.
When sensor information is associated to more than one person this ambiguity is resolved by sensor fusion or by manual means.
Information fusion Fusion techniques and methods are arranged to be used to support the process to make an automatic or manual threat evaluation for each person being screened. Fusion of information from several sensors of same or different types is applied in order to make information more reliable e.g. if one sensor indicates that it has detected a threat with a certain probability this indication may be either supported or contradicted by an indication from another sensor. In the first case the total probability for a true alarm is increased whereas in the later case the probability is decreased. The fusion of information both increases the probability of true detections and decreases the probability of false detections. The above described simple fusion of information decreases the number of different information sources the operator, or an automatic system, will have to asses in order to make a threat evaluation. More sophisticated techniques, e.g. fuzzy logic or neural network, may be applied in order to fuse information from several sources and produce information with higher reliability.
Threat evaluation and the security clearance decisions may be made manually by an operator or automatically by the system. When the sensor information associated to a certain person or persons, meets predetermined criteria, stored in the processing arrangement, an alert is arranged to be generated and presented at the operator panels.
Enabling sensors
As mentioned above the CMPSS system is not restricted to certain types of sensors. To detect various types of threats like Chemical, Biological, Radiological, Nuclear, Explosives or Weapon (CBRNEW), mentioned above, many types of sensors can be used. Some examples will be given below.
The main detection methods which are used by the system can be divided into two groups, bulk detection and trace detection . The bulk detection methods look for atomic elements or density coupled with imaging and use both active and passive sensors. Some bulk detection methods make it possible to deduce the amount of the substance in question. The trace detection methods work from trace amounts, e.g. of explosives in gas phase or in the form of particles. These traces are present around an object, on packing material or on the person or persons handling the object.
Several sensor technologies may be used to detect concealed items under clothing and within shoes. One suitable technology is low dose X-Ray, used e.g. in the product range Digital Radiographic Scanner (DRS). These products can investigate both persons and shoes and one supplier is the company Adani placed in Minsk in the Republic of Belarus. The sensor Rapiscan Secure 1000 supplied by Rapiscan Systems is also a type of a low dose active X-Ray sensor and is used to detect concealed weapons. Another suitable technology is based on the active or passive millimetre wave/THz sensors. The distinction between millimetre and THz frequency regions is somewhat ambiguous. An example of passive millimetre wave detection sensors is the system BIS-WDS GEN 2 supplied by Brijot Imaging Systems lnc and the system T4000 supplied by ThruVision Ltd in U.K. Active sensors of today exist for portal applications, for example L3 Communications' Provision, but development of stand-off sensors is in progress. These systems are able to detect all kind of concealed objects.
The low-dose X-ray Digital Radiographic Scanner (DRS) system can also be used for detection of objects and substances within the examined person's body in a manner known to the man skilled in the art.
The trace detection method which can be used for luggage or parcel-goods as well as for person examination is carried out by collection of particles or gases without touching the inspected object or person. To collect an air sample from an object or a person, the dislodging of substances is facilitated by puffs of air blowing at the object or the person. The air sample is then sucked into a spectroscopic sensor for analysis. This type of sensor is often called a sniffer. A sniffer is illustrated in figure 1 , 109, and in figure 4, 403. An example of trace detection sensors is the system PassPort supplied by L3 Communications. This sensor detects traces of explosives (E). Chemical, biological and explosive substances (CBE) can be detected by sensors based on Ion Mobility Spectrometry (IMS, patented by General Electric Security, GES) that currently is used in systems such as EntryScan by GES and lonscan Sentinel Il by Smiths Detection.
Shoe screening to detect objects and substances within the examined person's shoes during the movement through the system is performed with shoe screening sensors 404. These sensors normally comprise low-intensity X-ray screening of the foot and lower leg parts, which is performed during passage of the X-ray sensors 1 10 which can be collocated with the sniffer sensors 109, 403 or located at a separate X-ray station at a suitable position within the detection area.
To examine hand luggage or parcel-goods on a baggage track, conventional X-ray technology can be used for example Smiths-Heimann HI-SCAN 604Oi. To detect radiological and nuclear (RN) threats, detector technologies like Gamma-Ray detectors and Neutron detectors can be used. An example of a Gamma-Ray detector is the GammaCam which is a portable gamma ray imaging system provided by the EDO Corporation in the US, and an example of a Neutron detector is the Mobile Microspec Detector provided by the Bubble Technology Industries in Canada.
Miscellaneous
System properties that are adjustable, for example sensitivity levels of sensors and parameters in software modules, can be arranged to be modified in adaption to the present operational situation or information from external systems such as ticketing systems, adjacent surveillance systems, intell igence information databases and identification systems. The adjustments can be made either manually or automatically.
Entry to the system may be controlled in order to regulate the admission of people, e.g. by the gates 301 or other access control devices.
The sensors used in the CMPSS may be arranged to be integrated in the structure of the building where the CMPSS is installed, e.g. in walls.
The system can be arranged to be designed for stationary installation or mobile deployment.
The invention also provides a method for Concurrent Multi-Person Security Screening CMPSS, for security screening of persons passing a detection area, 1 05. The screening is performed by means of at least a cloth penetrating type of sensor 11 1 , 402 or sensors. Said sensor type or sensor types produces sensor information to a processing arrangement, 401. The processing arrangement comprises algorithms for threat analysis using the sensor information as input data and producing output information to operator panels 409, 410 wherein: • said sensors 109-111 , 303, 402-406 are positioned at defined positions within the detection area 105 and having a defined working area, whereas the positions and working area for each sensor being stored in the processing arrangement, • the CMPSS comprises a person tracking subsystem to assign an identification number to each person passing the detection area and continuously and automatically track each person during the passage through the detection area 105 and to define the position of each person within the detection area at all times, whereas the positions are transferred to the processing arrangement 401 , and
• the working area of each sensor and the position of persons are continuously compared in an association subsystem and when a person or persons is/are within the working area of one or several sensors, sensor information at that time is associated to the person or the persons being within the working area and
• when the sensor information associated to a certain person or persons meets predetermined criteria, stored in the processing arrangement 401 , an alert will be generated and presented at the operator panels 409, 410.
The invention is not limited to the embodiments and examples described above, but may vary freely within the scope of the appended claims.
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