Tailgating and reverse entry detection, alarm, recording and prevention using machine vision

Abstract

Unauthorized entry into controlled access areas using tailgating or reverse entry methods is detected using machine vision methods. Camera images of the controlled area are processed to identify and track objects in the controlled area. In a preferred embodiment, this processing includes 3D surface analysis to distinguish and classify objects in the field of view. Feature extraction, color analysis, and pattern recognition may also be used for identification and tracking of objects. Integration with security monitoring and control systems provides notification when a tailgating or reverse entry event has occurred. More reliable operation in practical circumstances is thus obtained, such as when multiple people are using an entrance or exit under variable light and shadow conditions. Electronic access control systems may further be combined with the machine vision methods of the invention to more effectively prevent tailgating or reverse entry.

1 . A method for detecting unauthorized passage of an object in regard to security of a controlled access area having a designated access point, comprising:
 (a) acquiring one or more stereoscopic images of an area of observation associated with the designated access point;   (b) analyzing the one or more images using a machine vision processing system to identify and classify an object in the area of observation, and further to determine the direction of motion of the object with respect to the designated access point; and   (c) applying one or more access control rules to the information obtained from the image analysis to determine whether the object is attempting to breach the controlled access area by using the designated access point in violation of the security of the controlled access area.   
   
   
       2 . The method of  claim 1 , in which the designated access point is an exit-only access point and the one or more access control rules determine whether the object is attempting to enter the controlled access area through the exit-only access point. 
   
   
       3 . The method of  claim 1 , in which the designated access point is limited to passage of objects that are classified in a defined object type and the one or more access control rules determine whether the classification of the object in the area of observation is in the defined object type. 
   
   
       4 . The method of  claim 3 , in which the designated access point is limited to passage of objects classified as vehicles. 
   
   
       5 . The method of  claim 3 , in which the designated access point is limited to passage of objects classified as packages. 
   
   
       6 . The method of  claim 3 , in which the designated access point is limited to passage of objects classified as persons. 
   
   
       7 . The method of  claim 1 , in which the designated access point is a one-way elevator and the one or more access control rules determine whether the object is attempting to enter the controlled access area via the exit of the one-way elevator. 
   
   
       8 . The method of  claim 1 , in which the designated access point is an escalator and the one or more access control rules determine whether the object is attempting to access the controlled access area by entering the escalator in a direction opposite to the operation of the escalator. 
   
   
       9 . The method of  claim 1 , in which the designated access point is a revolving structure and the one or more access control rules determine whether the object is attempting to access the controlled access area by entering the revolving structure in a direction opposite to the operation of the revolving structure. 
   
   
       10 . The method of  claim 1 , in which analyzing the one or more images further comprises determining the speed of motion of the object and the one or more access control rules determine whether the speed of motion of the object indicates a thrown object. 
   
   
       11 . The method of  claim 1 , in which analyzing the one or more images further comprises determining the trajectory of motion of the object and the one or more access control rules determine whether the trajectory of motion of the object indicates a thrown object. 
   
   
       12 . The method of  claim 1 , further comprising triggering an alarm when the one or more access control rules determine that the object is attempting to breach the controlled access area by using the designated access point in violation of the security of the controlled access area. 
   
   
       13 . The method of  claim 1 , further comprising causing an access limiting device associated with the designated access point to prevent breach of the controlled access area by the object. 
   
   
       14 . The method of  claim 13 , in which causing the access limiting device to prevent breach of the controlled access area comprises causing the access limiting device to block passage by the object with respect to the designated access point. 
   
   
       15 . The method of  claim 13 , in which causing the access limiting device to prevent breach of the controlled access area comprises locking the access limiting device. 
   
   
       16 . The method of  claim 1 , further comprising causing one or more access limiting devices to block passage of the object at the designated access point and contain the object within a defined area. 
   
   
       17 . The method of  claim 1 , further comprising receiving access control information from an access control system and applying the one or more access control rules to the access control information in combination with the information obtained from the image analysis to determine whether the object is attempting to breach the controlled access area. 
   
   
       18 . The method of  claim 17 , further comprising triggering an alarm when the one or more access control rules applied to the access control information and the information obtained from the image analysis determine that the object is attempting to breach the controlled access area by using the designated access point in violation of the security of the controlled access area. 
   
   
       19 . The method of  claim 17 , further comprising causing an access limiting device associated with the designated access point to prevent breach of the controlled access area by the object. 
   
   
       20 . The method of  claim 19 , in which causing the access limiting device to prevent breach of the controlled access area comprises causing the access limiting device to block passage by the object with respect to the designated access point. 
   
   
       21 . The method of  claim 19 , in which causing the access limiting device to prevent breach of the controlled access area comprises locking the access limiting device. 
   
   
       22 . The method of  claim 1 , in which analyzing the one or more images using a machine vision processing system further comprises using a three-dimensional surface analysis to identify the object. 
   
   
       23 . The method of  claim 1 , in which analyzing the one or more images using a machine vision processing system further comprises using a three-dimensional surface analysis to classify the object. 
   
   
       24 . The method of  claim 1 , further comprising recording the one or more images. 
   
   
       25 . The method of  claim 1 , further comprising recording information obtained from the image analysis. 
   
   
       26 . The method of  claim 1 , further comprising recording information resulting from applying the one or more access control rules to the information obtained from the image analysis. 
   
   
       27 . The method of  claim 1 , further comprising defining a region of interest within the area of observation. 
   
   
       28 . The method of  claim 27 , further comprising defining a plurality of regions of interest and applying the one or more access control rules based on the region of interest in which the object is located. 
   
   
       29 . The method of  claim 27 , further comprising using an interactive user interface that displays the area of observation to define the region of interest. 
   
   
       30 . The method of  claim 1 , further comprising using an interactive user interface to configure properties of the image analysis. 
   
   
       31 . The method of  claim 1 , further comprising using an interactive user interface to configure properties of the machine vision processing system. 
   
   
       32 . The method of  claim 1 , further comprising using an interactive user interface to configure properties of an access control system that provides access control information to the machine vision processing system. 
   
   
       33 . An apparatus for detecting a security violation with respect to a controlled access area having a designated access point, comprising:
 (a) a stereoscopic imaging device for acquiring one or more stereographic images of an area of observation; and   (b) a machine vision processing system in communication with the stereoscopic imaging device to receive the one or more images, the machine vision processing system being further configured to analyze the one or more images to identify and classify an object in the area of observation, and further to determine the direction of motion of the object with respect to the designated access point and apply one or more access control rules to the information obtained from the image analysis to determine whether the object is attempting to breach the controlled access area by using the designated access point in violation of security of the controlled access area.   
   
   
       34 . The apparatus of  claim 33 , in which the object in the area of observation is a suspect object, the apparatus further comprising a position sensor disposed on a background object in the area of observation, the machine vision processing system being further configured to use information received from the position sensor to define the background object from the suspect object. 
   
   
       35 . The apparatus of  claim 34 , in which the position sensor is disposed on a door. 
   
   
       36 . The apparatus of  claim 34 , in which the machine vision processing system is further configured to perform a calibration procedure that correlates position sensor information to a position of the background object for determining a background image. 
   
   
       37 . The apparatus of  claim 33 , in which the machine vision processing system is further configured to analyze the one or more images to determine the speed of motion of the object and apply the one or more access control rules to determine whether the speed of motion of the object indicates a thrown object. 
   
   
       38 . The apparatus of  claim 33 , in which the machine vision processing system is further configured to analyze the one or more images to determine the trajectory of motion of the object and apply the one or more access control rules to determine whether the trajectory of motion of the object indicates a thrown object. 
   
   
       39 . The apparatus of  claim 33 , further comprising an alarm that is triggered when the one or more access control rules determine that the object is attempting to breach the controlled access area in violation of the security of the controlled access area. 
   
   
       40 . The apparatus of  claim 33 , in which the object in the area of observation is a second object, the machine vision processing system being further configured to identify and classify a first object in the area of observation having supplied an authorization with respect to the controlled access area, and to apply the one or more access control rules to determine whether the second object is attempting to breach the controlled access area by utilizing the authorization supplied by the first object in violation thereof. 
   
   
       41 . The apparatus of  claim 40 , in which the one or more access control rules are configured to determine whether the second object is attempting to breach the controlled access area based on proximity of the second object to the first object in the area of observation. 
   
   
       42 . The apparatus of  claim 41 , in which the authorization of the first object is to enter the controlled access area, and the one or more access control rules are configured to determine whether the second object is attempting to enter the controlled access area by maintaining proximity to the first object as the first object enters the controlled access area. 
   
   
       43 . The apparatus of  claim 41 , in which the authorization of the first object is to exit the controlled access area, and the one or more access control rules are configured to determine whether the second object is attempting to enter the controlled access area by maintaining proximity to the first object as the first object exits the controlled access area. 
   
   
       44 . The apparatus of  claim 33 , further comprising an access control system associated with the controlled access area in which the access control system is configured to receive information from the object for accessing the controlled access area. 
   
   
       45 . The apparatus of  claim 44 , further comprising an access limiting device in communication with the access control system, in which the access control system is configured to control the operation of the access limiting device.