Abstract:
The invention is related to the systems of so-called “security entrance” and, in particular, to the systems for preventing the entry of forbidden articles and/or substances from an unprotected area to a protected one. The simplicity, efficiency and secrecy of examination in a security system for preventing the entry of forbidden articles and/or substances from a surrounding area to a protected one, said system comprised of a partitioning separating a protected area from an unprotected one, at least, one walk-gate made in said partitioning, an information control-and-processing device and a detector of forbidden articles and/or substances is achieved due to said detector of forbidden articles and/or substances made an X-ray kind to provide secret examination of every person passing through said walk-gate.

Description:
RELATED APPLICATIONS 
   This application is a Continuation of PCT application serial number PCT/BY2005/000007 filed on Aug. 5, 2005 (which was published in English under PCT Article 21(2) as International Publication No. WO 2006/015471 A1) which in turn claims priority to Belarus patent application number a 20040750 filed Aug. 9, 2004 both of which are incorporated herein by reference in their entirety. 

   BACKGROUND OF THE INVENTION 
   The invention is related to the systems of so-called “security entrance” and, in particular, to the systems for preventing the entry of forbidden articles and/or substances from an unprotected area to a protected one. 
   Known are a number of “security entrance” systems based on various concepts such as monitoring the entrance by means of radar devices [DE 19817396, Int. Cl.: G08B13/183, G01S13/04, Published Oct. 21, 1999] or the use of the pass cards equipped with IR-radiators [FR2831308, Int. Cl.: G08B13/19, Published Apr. 25, 2003]. Such systems make it possible to restrict the access to the protected area of the strangers but they are not suitable for providing a security entrance when most of those entering are casual visitors to the place like in the airports, railway terminals, bus stations as well as in the banks, large trading centers etc. These places nowadays present the greatest danger from the viewpoint of their susceptibility to various unlawful acts contemplating the use of both metal and plastic weapons including plastic explosives. 
   Known are the systems of security entrance employing a number of various methods that make it possible to reveal the attempts of entry of the weapons, explosives or drugs to the protected area. In [International Application WO9921148, Int.Cl.:G01V11/00, G01BV5/00, G08B23/00, G01N23/04, Published Apr. 29, 1999] there is described a sequential passage through a metal detector, a gas analyzer performing the analysis of the air samples from a person under examination and monitoring by means of ultrasonic radar sets. The possibility is provided to perform an X-ray check of hand luggage (bags, briefcases etc) but not the human check. Besides its lack of secrecy this kind of monitoring is also a very expensive one. 
   Not less complicated is a system of security entrance [U.S. Pat. No. 6,472,984, Int.Cl.:G08B21/00, Published Oct. 29, 2002] wherein a partitioning separating a protected area from an unprotected one is equipped with two or three walk-gates each provided with an appropriate door. A metal detector is used as a detector of forbidden articles. There is also available a weight control device of an examination zone and an information control-and-processing device. 
   Besides being very complicated and expensive such system do not provide the required secrecy of examination. 
   SUMMARY OF THE INVENTION 
   It is the aim of the present invention to design a comprehensive security system providing secret examination of every person passing through a walk-gate. 
   This aim is achieved by means of a security system for preventing the entry of forbidden articles and/or substances from a surrounding area to a protected one, said system comprised of a partitioning separating a protected area from an unprotected one, at least, one walk-gate made in said partitioning, an information control-and-processing device and a detector of forbidden articles and/or substances, wherein said detector of forbidden articles and/or substances is made an X-ray kind to provide secret examination of every person passing through said walk-gate. 
   At least one walk-gate in said partitioning is preferably supplied with at least one door with a respective drive mechanism connected to a drive signal output of an information control-and-processing device. 
   A detector of forbidden articles and/or substances is preferably supplied with an X-ray scanning radiation source and an X-ray receiver that is co-linear to said X-ray radiation and is connected to the information inputs of an information control-and-processing device. 
   An X-ray radiation source of said detector of forbidden articles and/or substances is made to generate a flat fan-shaped X-ray beam in the walk-gate plane and can be disposed behind the bottom part of one of the side walls of said walk-gate provided with, at least, one X-ray transparent portion or it can be built-in into said bottom part of one of said walk-gate side walls. 
   An X-ray receiver of said detector made as a vertical linear X-ray receiver can be built-in into the walk-gate element opposite to said X-ray radiation source, while preferably said element that is used to build-in said X-ray receiver is a movable door with a drive mechanism of said door made so that it maintains the pre-defined ratio of the door motion speed and of the scanning rate of an X-ray radiation source. 
   An X-ray receiver of said detector made as a vertical linear X-ray receiver can be disposed behind the walk-gate element opposite to said X-ray radiation source, for example, behind the walk-gate second side wall provided with, at least, one X-ray transparent portion. 
   An X-ray receiver of said detector made as a horizontal linear X-ray receiver can be disposed under the walk-gate floor provided with, at least, one X-ray transparent portion or built-in into said walk-gate floor. 
   An X-ray receiver of said detector made as a horizontal linear X-ray receiver can be disposed above the walk-gate ceiling provided with, at least, one X-ray transparent portion or built-in into said walk-gate ceiling. 
   Preferably a walk-gate is additionally supplied with a sensor to define the presence of a person ready to pass through said walk-gate with an output of said sensor being connected to the input for activating an X-ray radiation source. 
   The implementation examples of the present invention are illustrated in the following drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings: 
       FIG. 1  is a schematic diagram of an implementation example of a system filed wherein both an X-ray radiation source and an X-ray receiver are disposed behind the walk-gate walls: (a)—a front view, b—a plane view. 
       FIG. 2  is a schematic diagram of an implementation example of a system filed wherein an X-ray radiation source is disposed behind a walk-gate wall, and an X-ray receiver is disposed in a movable door: (a)—a front view, b—a plane view. 
       FIG. 3  is a schematic diagram of an implementation example of a system filed wherein an X-ray radiation source is disposed behind a walk-gate wall, and an X-ray receiver is disposed in a movable door: (a)—a front view, b—a plane view. 
       FIG. 4  is a schematic diagram of an implementation example of a system filed wherein an X-ray radiation source is disposed behind a walk-gate wall and, an X-ray receiver is disposed in said walk-gate wall: (a)—a front view, b—plane view. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A system filed according to any of its implementations is comprised of a partitioning  1  separating a protected area  2  from an unprotected area  3 . A partitioning  1  is comprised of at least one walk-gate  4  leading from an unprotected area  3  to a protected one. A walk-gate  4  is closed with, at least, one door  5  which is preferably made a movable one. A system also comprises a detector of forbidden articles and/or substances comprised of an X-ray radiation source  6  supplied with a collimator  7  for generating a flat fan-shaped X-ray beam  8  in the plane of a walk-gate  4  and an X-ray receiver  9  that is co-linear to said X-ray beam  8 . An X-ray receiver  9  in all implementations of a system filed is made a linear one and presents in itself a linear array of the elements for converting an X-ray radiation through a visible light into the digital electronic signals. Also there is provided an information control-and-processing device  10 . 
   In the implementation example presented in  FIG. 1  an X-ray radiation source  6  with a collimator  7  is located in the premises  11  that are disposed under the angle of 90° to a walk-gate  4  and are adjacent to a side-wall  12  wherein an X-ray transparent portion  13  is provided. In an opposite wall  14  of a walk-gate  4  there is also provided an X-ray transparent portion  15  with a vertical linear X-ray receiver  9  disposed further behind. An X-ray receiver is made a movable one so that it can be moved parallel to itself along a portion  15  in close synchronism with the scanning motion of an X-ray beam  8 . An information control-and-processing device  10  is made as a computer-controlled work station equipped with special software to process the image thus received and also to control the synchronous motion of a collimator  7  and of an X-ray receiver  9 . A walk-gate  4  is closed with a movable door  5 . A sensor for defining the presence of a person ready to pass through said walk-gate in the implementation example described is made as a video camera  16  though it can be made by any means known to those skilled in the art. 
   In the implementation example illustrated in  FIG. 3  an X-ray radiation source  6  with a collimator  7  are disposed in the premises  20  parallel to a walk-gate  4 . In their adjacent wall  21  there is provided an X-ray transparent portion  22 . An end wall of a walke-gate  4  is closed with a movable door  5  with a vertical linear X-ray receiver  9  secured there on. The system is additionally supplied with a horizontal X-ray receiver  23  (or  23 ’) disposed on the ceiling (or under the floor) of a walk-gate  4  across the latter, while the scanning flat fan-shaped X-ray beam  8  is generated in such a way that to enclose both a vertical detector  9  and a horizontal X-ray receiver  23 . An information control-and-processing device  10  is made as a computer-controlled work station equipped with special software to process the image thus received and also to control the synchronous motion of a collimator  7  and of an X-ray receiver  9 . A drive mechanism (not shown in the drawings) of a door  5  is made so that it maintains the pre-defined ratio of the door motion speed and of the scanning rate of an X-ray radiation source and is coupled to an output of an information control-and processing device  10 . 
   An X-ray radiation source  6  can be secured in the wall of a walk-gate  4 . However, the most preferable one is the position illustrated in  FIG. 4  with a an X-ray radiation source  6  and a collimator  7  disposed in the premises  24  adjacent to a walk-gate  4 , while an X-ray transparent portion  26  is provided in their adjacent wall  25 . A vertical linear X-ray receiver  9  is secured on the opposite wall  27  of a walk-gate  4 . A flat fan-shaped X-ray beam is generated in such a way that it could hit upon a vertical X-ray receiver  9  with high precision. Scanning is provided by means of the walk-gate floor  28  that is moving with a constant speed i.e. according to the principle of “a moving pavement” or an escalator. Such implementation of a system filed is especially suitable for the pedestrian subways in the airports where a wide use is made of such “moving pavements” or escalators. An information control-and-processing device  10  is made as a computer-controlled work station equipped with special software to process the image thus received and also to control the motion of the floor  28 . 
   The operation of the system filed is performed in the following way. 
   An X-ray radiation source emits a flow of X-ray beams to be shaped by a collimator  7  into one flat vertical X-ray beam  8 . 
   A collimator  7  and an X-ray receiver  9  are pre-set in such a manner that a vertical X-ray beam  8  hits upon an X-ray receiver  9  with high precision. 
   A highly precise synchronous movement can be provided, for example, by means of positioning a collimator  7  and an X-ray receiver  9  (or a door  5 ) on the respective horizontal guides and their movement there along said guides by means of the step motors (not shown in the drawings). 
   The synchronization design concepts of the motion system are described, for example, in [International Application WO02/7306, Int.Cl. G01N23/00, Published Apr. 4, 2002]. During scanning an X-ray receiver  9  is moved with a constant speed. A collimator  7  is moved in synchronism with the motion of an X-ray receiver  9  in such a manner that a slot shadow projection of a collimator  7  from an X-ray beam emitted by an X-ray radiation source  6  is constantly located on an X-ray receiver  9 . 
   As it follows from the similarity considerations to provide the constant projection of a collimator  7  on an X-ray receiver throughout the scanning range it is sufficient to perform the motion of both components with time according to one and the same law. Such design concept of a motion system makes it possible to provide its technical implementation by relatively simple means i.e. to make the motion a synchronous one a collimator  7  and an X-ray receiver  9  should be moved with constant speeds. 
   A synchronous motion of a collimator  7  and that of an X-ray receiver  9  is achieved due to highly precise ratio of their speeds. Since the rotational speed of the step motors is in the end defined by the switching rate of its windings to provide the synchronous motion it is necessary to synthesize the two frequencies having the precisely defined ratio. The possibility is also provided to vary said ratio in very small increments. 
   A sensor  24  for defining the presence of a person ready to pass through a walk-gate  4  supplies the signal of the presence of said person and in this way activates an X-ray radiation source  6 . A sensor  24  can be made, for example, as a video camera as it is shown in  FIG. 1 . 
   An X-ray beam  8  is passed through the X-ray transparent portions  13 ,  19 ,  22  or  26  of the walls  12 ,  18 ,  21 ,  25  ( FIGS. 1 ,  2 ,  3 ,  4  respectively) or without the latter and further through a human body  29  and then through an X-ray transparent portion  15  of a wall  14  ( FIG. 1 ) or directly ( FIGS. 2 ,  3  or  4 ) and at each given scanning interval it hits upon an X-ray receiver  9  with the resulting read-out of the electronic digital signals. The output electronic digital signals are supplied to the information control-and-processing device  10  that generates the image of a person  29  being examined. Due to the projection characteristics of the image thus received just one passing of a person being examined through a walk-gate provides the required information about the presence of forbidden articles and/or substances both on the surface and in the internal cavities of a human body. 
   To improve the safety of a system filed the latter can be additionally supplied with two more doors (not shown in the drawings) disposed after said movable door  5  and controlled by an information control-and-processing device  10 . These doors can be operated, for example, as it is described in [US 2003020607, Int.Cl. G08B21/00, Published Jan. 30, 2003]. After scanning a person  29  passes through a door  5  which is closed after him. Then before a person there is opened only one of the other two doors. If the analysis of the scanning image of a person under examination does not reveal any forbidden articles and/or substances, then there is opened one of the doors leading to the protected area. Should said analysis of the scanning image of a person under examination reveal some forbidden articles and/or substances, then there is opened another door leading to the inspection premises. The image analysis is performed by a computer-controlled work station or by more remote control devices. A person being examined is not aware of either the scanning or its results or of where the door he/or she is passing through leads to. 
   The maximum dose received by a person per one scanning is of 0.1 μZv which is in conformity with international radiation safety standards without any limitations as to the number of examinations including pregnant women and children. Such a low dose is achieved due to optimization of anode voltage and current of an X-ray radiation source  7  and the value of its output filter, the width of a collimator slot, the dimensions of X-ray sensitive components of an X-ray receiver  9  and the scanning time.