Tracking device, tracking method, and tracking system

Abstract

A tracking device for tracking a target object includes an interface connectable to a camera configured to acquire an image and determine a location of the object within the image and a distance therefrom, a memory that stores first coordinates that indicate a location of the camera with respect to a reference point in the facility, and a first direction towards which the camera faces, and a processor configured to calculate a second direction from the camera to the object based on the first direction and the location of the object, based on the second direction and the distance, calculate second coordinates indicating a location of the target object with respect to the location of the camera, based on the first and second coordinates, calculate third coordinates indicating a location of the target object with respect to the reference point, and store the calculated third coordinates in the memory.

What is claimed is: 
     
         1 . A tracking device for tracking a current location of a target object within a facility, comprising:
 an interface circuit connectable to a camera configured to acquire an image and determine a location of the target object within the acquired image and a distance between the target object and the camera;   a memory that stores
 first coordinates that indicate a location where the camera is installed with respect to a reference point predetermined in the facility, and 
 a first direction towards which the camera faces; and 
   a processor configured to
 upon receipt of the location of the target object and the distance from the camera,
 calculate a second direction from the camera to the target object based on the stored first direction and the received location of the target object within the image, 
 based on the calculated second direction and the received distance, calculate second coordinates indicating a location of the target object with respect to the location where the camera is installed, 
 based on the stored first coordinates and the calculated second coordinates, calculate third coordinates indicating a location of the target object with respect to the reference point of the facility, and 
 store, as the current location of the target object, the calculated third coordinates in the memory. 
 
   
     
     
         2 . The tracking device according to  claim 1 , wherein
 the second coordinates are polar coordinates indicating the location of the target object with respect to the location where the camera is installed.   
     
     
         3 . The tracking device according to  claim 2 , wherein
 the first coordinates are absolute coordinates indicating the location where the camera is installed with respect to the reference point of the facility, and   the third coordinates are absolute coordinates indicating the location of the target object with respect to the reference point.   
     
     
         4 . The tracking device according to  claim 1 , wherein
 the processor is configured to store time information indicating when the image of the target object is acquired by the camera, together with the calculated third coordinates in the memory.   
     
     
         5 . The tracking device according to  claim 1 , wherein
 the target object is a person, and   the location of the target object determined by the camera is a location where a head of the person is located within the image.   
     
     
         6 . The tracking device according to  claim 5 , wherein
 the facility is a sales room of a store.   
     
     
         7 . The tracking device according to  claim 1 , wherein
 the processor is configured to
 calculate a moving velocity of the target object based on the calculated third coordinates and previous third coordinates indicating a previous location of the target object, and 
 determine that the received second direction is erroneous when the moving velocity is equal to or greater than a predetermined threshold. 
   
     
     
         8 . The tracking device according to  claim 7 , wherein
 the processor is configured to, upon determining that the second direction is erroneous, correct the calculated second coordinates using a previous second direction acquired by the camera, and recalculate the third coordinates using the corrected second coordinates.   
     
     
         9 . The tracking device according to  claim 1 , wherein
 the processor is configured to repeat a process of the calculation of the second direction, the second coordinates, and the third coordinates, and the storage thereof as long as the target object is located within the image.   
     
     
         10 . The tracking device according to  claim 9 , wherein
 the processor is configured to
 determine that a previous location of the target object is within an edge region of the image, and 
 when the previous location is within the edge region and a predetermined time has elapsed without receiving the location and the distance from the camera, stop repeating the process. 
   
     
     
         11 . A method for tracking a current location of a target object within a facility, the method comprising:
 storing
 first coordinates that indicate a location where a camera is installed with respect to a reference point predetermined in the facility, and 
 a first direction towards which the camera faces; 
   acquiring an image by the camera and determining a location of the target object within the acquired image and a distance between the target object and the camera;   calculating a second direction from the camera to the target object based on the stored first direction and the acquired location of the target object;   based on the calculated second direction and the acquired distance, calculating second coordinates indicating a location of the target object with respect to the location where the camera is installed;   based on the stored first coordinates and the calculated second coordinates, calculating third coordinates indicating a location of the target object with respect to the reference point of the facility; and   storing, as the current location of the target object, the calculated third coordinates.   
     
     
         12 . The method according to  claim 11 , wherein
 the second coordinates are polar coordinates indicating the location of the target object with respect to the location where the camera is installed.   
     
     
         13 . The method according to  claim 12 , wherein
 the first coordinates are absolute coordinates indicating the location where the camera is installed with respect to the reference point of the facility, and   the third coordinates are absolute coordinates indicating the location of the target object with respect to the reference point.   
     
     
         14 . The method according to  claim 11 , further comprising:
 storing time information indicating when the image of the target object is acquired by the camera, together with the calculated third coordinates.   
     
     
         15 . The method according to  claim 11 , wherein
 the target object is a person, and   the location of the target object determined by the camera is a location where a head of the person is located within the image.   
     
     
         16 . The method according to  claim 15 , wherein
 the facility is a sales room of a store.   
     
     
         17 . The method according to  claim 11 , further comprising:
 calculating a moving velocity of the target object based on the calculated third coordinates and previous third coordinates indicating a previous location of the target object; and   determining that the received second direction is erroneous when the moving velocity is equal to or greater than a predetermined threshold.   
     
     
         18 . The method according to  claim 17 , further comprising:
 upon determining that the second direction is erroneous, correcting the calculated second coordinates using a previous second direction acquired by the camera, and recalculating the third coordinates using the corrected second coordinates.   
     
     
         19 . The method according to  claim 11 , further comprising:
 repeating a process of the calculation of the second direction, the second coordinates, and the third coordinates, and the storage thereof as long as the target object is located within the image.   
     
     
         20 . A tracking system comprising:
 a camera configured to acquire an image and determine a location of the target object within the acquired image and a distance between the target object and the camera; and   a tracking device including
 a memory that stores 
 first coordinates that indicate a location where the camera is installed with respect to a reference point predetermined in the facility, and 
 a first direction towards which the camera faces, and 
   a processor configured to
 upon receipt of the location of the target object and the distance from the camera,
 calculate a second direction from the camera to the target object based on the stored first direction and the received location of the target object, 
 based on the calculated second direction and the received distance, calculate second coordinates indicating a location of the target object with respect to the location where the camera is installed, 
 based on the stored first coordinates and the calculated second coordinates, calculate third coordinates indicating a location of the target object with respect to the reference point of the facility, and 
 store, as the current location of the target object, the calculated third coordinates in the memory.