Abstract:
A system is provided for controlling access at a personnel control gate, comprising: a proximity reader ( 38 ) connected to the control gate ( 36 ) for controlling access through the control gate; and an ancillary reader ( 40 ) located adjacent to the proximity reader, the ancillary reader enabled to return an RF transponder ( 48 ) signal recognizable by the proximity reader whenever the ancillary reader detects an authorized access code present on an ID badge ( 20 ), thereby causing the proximity reader to control the control gate and allow the bearer of the ID badge access through the control gate.

Description:
FIELD OF THE INVENTION 
   This invention is in the field of personnel access control systems. More particularly it is in the field of access control systems for providing limited or temporary access of personnel to a facility. 
   BACKGROUND OF THE INVENTION 
   Many organizations desire to limit access to their facilities and work sites to authorized persons only. Typical among these organizations are private companies, universities, schools, governmental agencies, military installations, and the like. Means for access control frequently involve the use of ID badge readers which in turn are linked to automatic gates or turnstiles. These automatic gates are activated to admit a person only when a valid badge is read by the reader. Often ID badges have a picture printed thereon of the badge-holder which provides an extra measure of security. 
   While there are a number of types of badge readers in use, an increasingly popular type is the proximity reader which does not require a badge to be physically inserted or run past a read head to operate. Proximity reader systems operate with ID badges which contain a radio frequency identification (RFID) device. An RFID is an electronic device, able to be made very thin and easily incorporated as part of an ID badge. RFIDs require no power source of their own to operate. The RFID device operates as a transponder and transmits stored information when held near a badge reader which in turn contains an RF transceiver tuned to the frequency of the RIFD. If the information transmitted by the RFID transponder is recognized as valid by the proximity reader, the gate is opened and the badge-holder is allowed access to the facility. 
   Since this type of RFID-containing proximity badge takes some time to make and is relatively expensive, they are not usually used for visitors and others who require only temporary authorization to enter a facility. Most often used is a simple paper badge having no image or other visitor ID which is filled out manually by a security guard. Such an ID badge is easily counterfeited and represents a security loophole that increases the risk that an unauthorized person will gain entry to a confidential or secure area. 
   Thus there exists a need to provide a badge making system that can quickly make inexpensive badges which may be used for visitors or other persons for whom access control is desired on a temporary basis, and which also may be recognized by an automatic access control gates controlled by proximity readers. 
   SUMMARY OF THE INVENTION 
   In answer to these and other problems of the prior art, in accordance with the present invention there is provided a system for controlling access at a personnel control gate, comprising: a proximity reader connected to the control gate for controlling access through the control gate, and an ancillary reader located adjacent to the proximity reader, the ancillary reader enabled to return an RF transponder signal recognizable by the proximity reader whenever the ancillary reader detects an authorized access code present on an ID badge, thereby causing the proximity reader to control the control gate and allow the bearer of the ID badge access through the control gate. 
   In accordance with another aspect of the present invention, there is also provided a system for controlling access of at least one personnel control gate, comprising: an image capture device for capturing a digital image of a visitor and storing the digital image as a data file; a computer for receiving the digital image data file, the processor enabled to embed an authorized access code in the image data file steganographically, the computer further enabled to receive additional information relative to the visitor; a printer connected to the computer for printing a ID badge, the ID badge having the image of the visitor with the authorized access code steganographically embedded in the image, the ID badge having the additional information printed thereon; a proximity reader cooperating with at least one personnel control gate to control access through the control gate; and an ancillary reader located adjacent to the proximity reader, the ancillary reader enabled to return an RF transponder signal recognizable by the proximity reader whenever the ancillary reader detects the authorized access code steganographically embedded in the image of the visitor printed on the ID badge, thereby causing the proximity reader to control the control gate and allow the visitor bearing the ID badge access through the control gate. 
   In accordance with yet another aspect of the present invention there is also provided a method for controlling access at a personnel control gate, comprising: detecting by an ancillary reader an authorized access code contained on an ID badge engaged therewith, the ancillary reader being placed adjacent to a proximity reader, the proximity reader cooperating with the personnel control gate to control the gate; enabling the ancillary reader when the access code is detected to return an RF transponder signal recognizable by the adjacent proximity reader; and activating the proximity reader upon recognizing the RF transponder signal from the ancillary reader to control the control gate and allow a bearer of the ID badge access through the control gate. 
   These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the detailed description of the preferred embodiments of the invention presented below, reference is made to the accompanying drawings in which: 
       FIG. 1  depicts a schematic diagram for a personnel access control system made in accordance with the present invention; 
       FIG. 2  is a detailed illustration of an ID badge made in accordance with the present invention; 
       FIG. 3  depicts a schematic diagram of the component parts of ancillary reader made in accordance with the present invention; and 
       FIG. 4  shows a flow diagram of the steps in the operation of a preferred embodiment of the personnel access control system of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Turning first to  FIG. 1 , there is shown a schematic diagram for a personnel access control system  10  made in accordance with the present invention. A badge printing station  12  is located, for example at a main entry portal of a facility where it is desired to control access by personnel. An image capture device  14 , typically a conveniently mounted digital camera, is used to capture a digital image of a visitor or other individual for whom it is desired to provide temporary access to the facility. The image data file of the captured image is transferred to and stored in a database  17  of computer  16 . Computer  16  is also used to enter, and store in association with the image data file, the visiting or temporary individual&#39;s name, date and length of visit, or any other visitor identifying information such as driver&#39;s license number, social security number, and the like, which is required. 
   The computer  16  is also used to associate an authorized access code with the individual&#39;s other stored data. This authorized access code is a unique identifier which operates much like the very familiar Personal Identification Number (PIN) used by the bearer of a transaction card to activate the card. Any unique numeric or alphanumeric code may be used for the access code in the present invention, however. When a reader at a control gate which is programmed to recognize the authorized access code is engaged with a badge containing the code, the reader then cooperates with the control gate to admit the bearer of the access code. 
   For the present invention, the authorized access code is incorporated directly on the ID badge in the form of a visually indiscernible indicia which has been embedded in the visitor&#39;s previously captured and stored digital image file. When the visitor&#39;s badge is printed, the visitor&#39;s image containing this embedded code is printed on it. A means well known in the art for embedding such a visually indiscernible indicia in a digital image file is the data hiding technique known as steganography, or digital watermarking. The presence of such an indiscernible indicia or digital watermark may be detected and the access code extracted only by an appropriately equipped reader. In addition to providing a means of incorporating the authorized access code, the presence of the digital watermark also serves to authenticate the ID badge, for example by preventing a false badge being created by substituting an image which has no digital watermark. A digital watermarking technique particularly useful for hiding data in an image steganographically in this way is disclosed in commonly assigned U.S. Pat. No. 5,859,920 to Daly, et al., and the method of Daly et al. is hereby incorporated in its entirety by reference. 
   Badge printer  18  is used to print an ID badge  20  for the visitor. Badge printer  18  may be any digital printer capable of printing text and images, for example a laser electrophotographic printer, or an ink jet or thermal dye transfer printer. 
   Turning now to  FIG. 2 , there is provided a more detailed illustration of an ID badge  20  made in accordance with the present invention. ID badge  20  may be constructed from any of the well-known digital print media available in the marketplace for the various kinds of printers useful for badge printer  18 . Typically, media useful for ID badges include paper print media of varying thickness and weight. The print media may also include an overcoat or image receiving layer as dictated by the printer employed. In addition, composite or plastic sheet media may be used in combination with an appropriate image receiving layer. Badges may be printed on individual pre-cut blanks of media which are fed to a printer, or may be cut from a sheet of media as needed by use of any well-known method of the prior art, such as use of media with pre-perforated badge-shaped blanks (not shown), or by use of a simple die cutter (not shown) to cut a printed badge from a roll of media. 
   Shown printed on ID badge  20  is the name and/or logo of the facility  22  for which access by personnel is being controlled. Also printed on ID badge  20  are the name  24  of the person for whom the badge is created, and the date  26  when the ID badge  20  is valid and can be used to gain entry to the facility. Although not shown in  FIG. 2 , it will be understood that the valid date  26  may also be represented as any period of time, ranging, for example, from only a few minutes or an hour to several days or longer, when the ID badge may be used to gain entry. The visitor&#39;s image  28 , as previously discussed, has steganographically embedded in it a visually indiscernible indicia  30  containing an access code which is detectable when the ID badge  20  is engaged with an appropriate reader. The operation of this reader will be described in detail later. It will be readily understood by those of skill in the art that the visually indiscernible indicia  30  may be present on the ID badge  20  at other locations, including in the background pattern image  32 , or present at a plurality of locations on the ID badge  20 . 
   Returning now to  FIG. 1 , there is also shown an access control station  34  where control gate  36  physically controls access by personnel to a facility or a designated area within a control perimeter. There is provided at access control station  34  a proximity reader  38  which interrogates proximity ID badges by means of a radio transceiver when such a badge is held physically close to the proximity reader  38  by a badge holder. As described previously, such a proximity badge contains a radio frequency identification (RFID) device which acts as a transponder when it is interrogated by the proximity reader  38  and sends a access code value to the proximity reader  38 . If the access code sent matches an authorized access code stored by the proximity reader  38 , the proximity reader  38  cooperates with control gate  36  to activate the opening of it to admit the badge holder to the controlled area. 
   Ancillary reader  40 , is located adjacent to proximity reader  38  in access control station  34 , but not so close as to interfere with the engaging of proximity ID badges, and is used to read an ID badge such as the ID badge  20  illustrated in  FIG. 2 . In reference now to  FIG. 3 , there is illustrated a block diagram of the component parts of ancillary reader  40 . When ID badge  20  is engaged with ancillary reader  40 , image sensor  42  scans visitor&#39;s image  28  on ID badge  20  and produces a digital image file of the visitor&#39;s image  28 . Image sensor  42  may comprise, for example, a linear array or an area array scanner (neither shown). However, any appropriate image sensor may be used. The digital image file is stored in memory  44  and is analyzed by processor  46  which detects the presence of steganographically embedded visually indiscernible indicia  30  and extracts and decodes the access code as described previously. 
   While the various components of ancillary reader  40  are shown in  FIG. 3  as individual components, it will be recognized that memory  44  and processor  46  may conveniently be combined in an application specific integrated circuit (ASIC). It will be also be recognized that image sensor  42 , memory  44  and processor  46  components of ancillary reader  40  may be a fully integrated device such as a digital camera especially adapted to the purpose. 
   Also stored in memory  44  of ancillary reader  40  are previously programmed access codes authorized to be valid under predetermined conditions. For example, a particular access code may be authorized to admit a visitor on a particular date or series of dates. Other codes may be authorized to admit only at certain times of day, for example on just one work shift or other. Still other codes may permit access only at certain gates and not others. Authorized access codes may be changed and reprogrammed as needed either by reprogramming each reader at each gate individually or through a networked system where all readers at an installation are linked to a central control facility by a wired communications channel or a wireless network (not shown). If the access code extracted from the ID badge matches an authorized access code stored in memory  44 , then processor  46  enables radio frequency (RF) transponder  48  to return the authorized access code value via antenna  41  to proximity reader  38 . Thus the signal from transponder  48  exactly mimics the resulting signal which would have been received by proximity reader  38  if it had interrogated directly a proximity badge containing an RFID transponder containing the access code. When proximity reader  38  receives an authorized access code from transponder  48 , it cooperates with control gate  36  to admit the visitor. 
   In order to provide a more clear understanding of the invention, the steps required in its practice will now be described in detail.  FIG. 4  is a flow diagram of the steps in the operation of a preferred embodiment of the personnel access control system of  FIG. 1 . At step  100 , a visitor&#39;s name and any other required identification information for the visitor is entered into computer  16  at badge printing station  12  using an input device such as a keyboard or touch screen. Then at step  102  an image of the visitor is captured and the resulting image file stored. Next, in step  104 , an authorized access code is embedded in the image file steganographically by computer  16 . The visitor&#39;s name and image data is now compiled by computer  16  and printed on ID badge  20  by badge printer  18  in step  106 . 
   When a visitor carrying a ID badge approaches an access control gate where entry is desired, he or she engages the ID badge with ancillary reader  40  (step  108 ). In step  110 , ancillary reader  40  detects the presence of the visually indiscernible indicia embedded in step  104  and extracts the access code from it. In step  112  the extracted access code is compared to the authorized codes stored in computer  16 . If the extracted code does not match a preprogrammed authorized code then a “rejected” signal is provided to the visitor in step  114  via a display device such as a display lamp or screen. If the access code does match a stored authorized code, then the ancillary reader enables the transponder  48  to reply with an authorized access code to proximity reader  38  in step  116 . It is understood that proximity readers are activated when an object such as an ID card is placed at a minimum distance from the reader. That activation process can be supplied from the activated auxiliary reader either by physical means: such as by moving the antenna from the auxiliary reader closer to the proximity reader; or by electronic means such as by boosting the signal strength of the signal returned from the auxiliary reader&#39;s transponder. In step  118  the proximity reader is activated and cooperates with control gate  36  to admit the visitor. 
   It will be understood that while the invention has been described with respect to an embodiment where an authorized access code is provided as a visually indiscernible mark steganographically embedded in a ID badge, the invention will also operate equally well where the authorized access code is incorporated by other methods. For example, the authorized access code may be encoded in the form of a machine readable bar code. This bar code is then printed on the ID badge along with the visitor&#39;s image and other information as described previously. In this embodiment, the ancillary reader comprises a bar code reader which reads the bar code when the ID badge is engaged with it at a control gate. If the bar code read by the ancillary reader matches the pre-programmed authorized access code stored by the reader, the transponder of the ancillary reader is activated in a manner analogous to that already described for the other embodiments disclosed. With this embodiment, for security reasons, it may be desirable to change the bar coded access code frequently, for example on a daily basis, or even more frequently. Changing the access code frequently will in turn necessitate reprogramming the ancillary readers with the new authorized access codes often, but this is easily accomplished by a networked system where all readers at an installation are linked to a central control facility by a wired communications channel or a wireless network as described previously. 
   The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that still other variations and modifications can be effected within the scope of the invention. 
   
     
       
             
           
             
             
           
         
             
                 
             
             
               PARTS LIST 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               10 
               Personnel access control system 
             
             
               12 
               Badge printing station 
             
             
               14 
               Image capture device 
             
             
               16 
               Computer 
             
             
               17 
               Database 
             
             
               18 
               Badge printer 
             
             
               20 
               ID badge 
             
             
               22 
               Facility 
             
             
               24 
               Name 
             
             
               26 
               Date 
             
             
               28 
               Visitor&#39;s image 
             
             
               30 
               Visually indiscernible indicia 
             
             
               32 
               Background pattern image 
             
             
               34 
               Access control station 
             
             
               36 
               Control gate 
             
             
               38 
               Proximity reader 
             
             
               40 
               Ancillary reader 
             
             
               41 
               Antenna 
             
             
               42 
               Image sensor 
             
             
               44 
               Memory 
             
             
               46 
               Processor 
             
             
               48 
               RF transponder 
             
             
               100 
               Step 
             
             
               102 
               Step 
             
             
               104 
               Step 
             
             
               106 
               Step 
             
             
               108 
               Step 
             
             
               110 
               Step 
             
             
               112 
               Step 
             
             
               114 
               Step 
             
             
               116 
               Step 
             
             
               118 
               Step