Video tracking system and method

Abstract

A video tracking system and method which includes a video camera having a selectively adjustable panning orientation, tilting orientation and focal length. A processor receives video images acquired by the camera. The processor is programmed to detect target objects in the images and selectively adjust the camera to track the target object. The camera is adjusted at variable rates which are selected as a function of a property, such as the velocity, of the target object. The focal length of the camera is selectively adjusted as a function of the distance of the target object from the camera. The images acquired by the camera are geometrically transformed to align images having different fields of view to facilitate the analysis of the images and thereby allowing the camera to be continuously adjustable for the production of video images having relatively smooth transitional movements.

What is claimed is:  
     
         1 . A video tracking system comprising: 
 a video camera having a field of view, said camera being selectively adjustable wherein adjustment of said camera varies the field of view of said camera; and    at least one processor operably coupled to said camera wherein said processor receives video images acquired by said camera and selectively adjusts said camera; said processor programmed to detect a moving target object in said video images and adjust said camera to track said target object, said processor adjusting said camera at a plurality of varied adjustment rates.    
     
     
         2 . The video tracking system of  claim 1  wherein said processor selects the adjustment rate of said camera as a function of at least one property of the target object.  
     
     
         3 . The video tracking system of  claim 2  wherein the at least one property of the target object includes a velocity of the target object.  
     
     
         4 . The tracking system of  claim 2  wherein said processor is programmed to select the adjustment rate of said camera based upon analysis of a first image and a second image wherein said first image is acquired by said camera adjusted to define a first field of view and said second image is acquired by said camera adjusted to define a second field of view.  
     
     
         5 . The tracking system of  claim 4  wherein said first and second fields of view are partially overlapping and wherein determination of said selected adjustment rate by said processor includes identifying and aligning at least one common feature represented in each of said first and second images.  
     
     
         6 . The tracking system of  claim 1  wherein said camera has a selectively adjustable focal length and said processor selects the focal length of said camera as a function of the distance of the target object from said camera.  
     
     
         7 . The tracking system of  claim 1  wherein said camera is adjusted at a first selected adjustment rate until said processor selects a second adjustment rate and communicates said second adjustment rate to said camera.  
     
     
         8 . The tracking system of  claim 4  wherein said camera defines a third field of view as said camera is being adjusted at said selected adjustment rate and wherein a third image is acquired by said camera when defining said third field of view, said first, second and third images being consecutively analyzed by said processor.  
     
     
         9 . The tracking system of  claim 1  wherein said camera is selectively adjustable at a variable rate in adjusting at least one of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         10 . The tracking system of  claim 1  wherein selective adjustment of said camera includes selective panning movement of said camera, said panning movement defining an x-axis, selective tilting movement of said camera, said tilting movement defining a y-axis, and selective focal length adjustment of said camera, adjustment of the focal length defining a z-axis, said x, y and z axes oriented mutually perpendicular.  
     
     
         11 . The tracking system of  claim 10  wherein said processor adjusts said camera at a selected panning rate, said selected panning rate being a function of the velocity of said target object along said x-axis and said processor adjusts said camera at a selected tilting rate, said selected tilting rate being a function of the velocity of said target object along said y-axis.  
     
     
         12 . The tracking system of  claim 1  further comprising a display device and an input device operably coupled to said system wherein an operator may view said video images on said display device and input commands or data into said system through said input device, said display device and input device being positionable remote from said camera.  
     
     
         13 . A video tracking system comprising: 
 a video camera having a field of view, said camera being selectively adjustable wherein adjustment of said camera varies the field of view of said camera; and    at least one processor operably coupled to said camera wherein said processor receives video images acquired by said camera and selectively adjusts said camera; said processor programmed to detect a moving target object in said video images and estimate a target value, said target value being a function of a property of said target object, said processor adjusting said camera at a selected adjustment rate, said selected adjustment rate being a function of said target value.    
     
     
         14 . The video tracking system of  claim 13  wherein said camera is selectively adjustable at a variable rate in adjusting at least one of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         15 . The tracking system of  claim 13  wherein selective adjustment of said camera includes selective panning movement of said camera, said panning movement defining an x-axis, selective tilting movement of said camera, said tilting movement defining a y-axis, and selective focal length adjustment of said camera, adjustment of the focal length defining a z-axis, said x, y and z axes oriented mutually perpendicular.  
     
     
         16 . The tracking system of  claim 15  wherein said processor adjusts said camera at a selected panning rate, said selected panning rate being a function of the velocity of said target object along said x-axis and said processor adjusts said camera at a selected tilting rate, said selected tilting rate being a function of the velocity of said target object along said y-axis.  
     
     
         17 . The tracking system of  claim 13  wherein said processor is programmed to estimate said target value based upon a first image and a second image wherein said first image is acquired by said camera adjusted to define a first field of view and said second image is acquired by said camera adjusted to define a second field of view.  
     
     
         18 . The tracking system of  claim 17  wherein said first and second fields of view are partially overlapping and wherein determination of said selected adjustment rate by said processor includes identifying and aligning at least one common feature represented in each of said first and second images.  
     
     
         19 . The tracking system of  claim 17  wherein said camera is adjusted at a first selected adjustment rate until said processor selects a second adjustment rate and communicates said second adjustement rate to said camera.  
     
     
         20 . The tracking system of  claim 19  wherein said camera defines a third field of view as said camera is adjusted at said selected adjustment rate and wherein a third image is acquired by said camera when defining said third field of view, said first, second and third images being consecutively analyzed by said processor.  
     
     
         21 . The tracking system of  claim 13  wherein said camera has a selectively adjustable focal length and said processor selects the focal length of said camera as a function of the distance of the target object from said camera.  
     
     
         22 . The tracking system of  claim 13  further comprising a display device and an input device operably coupled to said system wherein an operator may view said video images on said display device and input commands or data into said system through said input device, said display device and input device being positionable remote from said camera.  
     
     
         23 . A video tracking system comprising: 
 a video camera having a field of view, said camera being selectively adjustable wherein adjustment of said camera varies the field of view of said camera; and    at least one processor operably coupled to said camera wherein said processor receives video images acquired by said camera and selectively adjusts said camera; said processor programmed to detect a moving target object in said video images and adjust said camera and track said target object and wherein during tracking of the target object said processor communicates a plurality of commands to said camera, said camera being continuously and variably adjustable in accordance with said commands without an intervening stationary interval.    
     
     
         24 . The video tracking system of  claim 23  wherein said camera is selectively adjustable at a variable rate in adjusting at least one of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         25 . The tracking system of  claim 23  wherein said commands includes a first command adjusting said camera at a selected rate and direction until a second command is received by said camera.  
     
     
         26 . The tracking system of  claim 25  wherein said processor adjusts said camera at a selectively variable panning rate and at a selectively variable tilting rate.  
     
     
         27 . The tracking system of  claim 23  wherein said camera acquires images for analysis by said processor while being adjusted.  
     
     
         28 . The tracking system of  claim 23  wherein continuous and variable adjustment of said camera includes varying one of a direction of adjustment and a rate of adjustment.  
     
     
         29 . A video tracking system comprising: 
 a video camera having a field of view, said camera being selectively adjustable wherein adjustment of said camera varies the field of view of said camera; and    at least one processor operably coupled to said camera wherein said processor receives video images acquired by said camera and selectively adjusts said camera; said processor programmed to detect a moving target object in said video images and adjust said camera and track said target object wherein said processor consecutively analyzes first, second and third images acquired by said camera, each of said images recording a different field of view, said processor communicating to said camera a first command selectively adjusting said camera and a second command selectively adjusting said camera; said camera being adjusted in accordance with said first command during at least a portion of a first time interval between acquisition of said first and second images, said camera being adjusted in accordance with said second command during at least a portion of a second time interval between acquisition of said second and third images and wherein said camera is continuously adjusted between acquisition of said first image and said third image.    
     
     
         30 . The video tracking system of  claim 29  wherein said camera is selectively adjustable at a variable rate in adjusting at least one of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         31 . The tracking system of  claim 29  wherein said first command adjusts said camera at a selected rate and direction until said second command is received by said camera.  
     
     
         32 . A method of tracking a target object with a video camera, said method comprising: 
 providing a video camera having a field of view, said camera being selectively adjustable wherein adjustment of said camera varies the field of view of said camera; and    adjusting said camera at a selectively variable adjustment rate to track a target object.    
     
     
         33 . The method of  claim 32  wherein said camera is adjusted at an adjustment rate which is selected as a function of at least one property of the target object.  
     
     
         34 . The method of  claim 33  wherein the at least one property of the target object includes a velocity of the target object.  
     
     
         35 . The method of  claim 33  wherein said adjustment rate is selected based upon analysis of a first image and a second image wherein said first image is acquired by said camera adjusted to define a first field of view and said second image is acquired by said camera adjusted to define a second field of view.  
     
     
         36 . The method of  claim 35  wherein said first and second fields of view are partially overlapping and wherein determination of said adjustment rate includes identifying and aligning at least one common feature represented in each of said first and second images.  
     
     
         37 . The method of  claim 35  wherein determination of said adjustment rate includes the use of a proportionality factor which is a function of the real world distance between the target object and said camera.  
     
     
         38 . The method of  claim 32  wherein said camera is adjusted at a first selected adjustment rate until said processor selects a second adjustment rate and communicates said second adjustment rate to said camera.  
     
     
         39 . The method of  claim 32  wherein adjusting said camera at a selectively variable adjustment rate comprises adjusting at least one of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         40 . The method of  claim 32  wherein said camera is selectively adjustable at a variable rate in adjusting each of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         41 . The method of  claim 32  wherein said camera is selectively adjustable at a variable rate in adjusting each of a panning orientation of said camera and a tilt orientation of said camera, and wherein each of said variable adjustment rates are selected as a function of the velocity of the target object.  
     
     
         42 . A method of tracking a target object with a video camera, said method comprising: 
 providing a video camera having a field of view, said camera being selectively adjustable wherein adjustment of said camera varies the field of view of said camera;    detecting a target object in images acquired by said camera;    estimating a target value which is a function of at least one property of the target object; and    adjusting said camera at a selectively variable rate wherein said adjustment rate of said camera rate is selected as a function of said target value.    
     
     
         43 . The method of  claim 42  wherein the at least one property of the target object includes a velocity of the target object.  
     
     
         44 . The method of  claim 42  wherein adjusting said camera at a selectively variable adjustment rate includes selecting said adjustment rate based upon analysis of a first image and a second image wherein said first image is acquired by said camera adjusted to define a first field of view and said second image is acquired by said camera adjusted to define a second field of view.  
     
     
         45 . The method of  claim 44  wherein said first and second fields of view are partially overlapping and wherein determination of said adjustment rate includes identifying and aligning at least one common feature represented in each of said first and second images.  
     
     
         46 . The method of  claim 42  wherein the camera has a selectively adjustable focal length and the method further comprises adjusting the focal of said camera as a function of the distance of the target object from the camera.  
     
     
         47 . The method of  claim 42  wherein adjusting the camera further comprises adjusting the camera at a first selected adjustment rate until a second selected adjustment rate is communicated to the camera.  
     
     
         48 . The method of  claim 42  wherein adjusting said camera at a selectively variable adjustment rate comprises adjusting at least one of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         49 . The method of  claim 42  wherein adjusting said camera at a selectively variable adjustment rate includes selectively adjusting at a variable rate each of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         50 . The method of  claim 42  wherein the step of adjusting said camera includes selecting a first adjustment rate and direction for adjusting the camera and continuing to adjust the camera at the first adjustment rate and direction until a second adjustment rate and direction are selected.  
     
     
         51 . A method of tracking a target object with a video camera, said method comprising: 
 providing a video camera having a field of view, said camera being selectively adjustable wherein adjustment of said camera varies the field of view of said camera; and    adjusting said camera to track a target object wherein said adjustment of said camera includes selectively and variably adjusting at least one adjustment parameter and wherein said camera is continuously adjustable during said selective and variable adjustment of said at least one adjustment parameter.    
     
     
         52 . The method of  claim 51  wherein selectively and variably adjusting said at least one adjustment parameter of said camera includes the adjustment of at least one of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         53 . The method of  claim 51  wherein selectively and variably adjusting said at least one adjustment parameter of said camera includes adjusting said camera at a selectively variable rate in the adjustment of at least one of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         54 . The method of  claim 51  wherein selectively and variably adjusting said at least one adjustment parameter of said camera includes adjusting said camera at a selectively variable rate in the adjustment of each of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         55 . The method of  claim 54  wherein said selective and variable adjustment of said at least one adjustment parameter includes varying one of a direction of adjustment and a rate of adjustment.  
     
     
         56 . The method of  claim 54  wherein at least one of the adjustment parameters are adjusted at a variable adjustment rate selected as a function of the velocity of the target object.  
     
     
         57 . A method of tracking a target object with a video camera, said method comprising: 
 providing a video camera having a field of view, said camera being selectively adjustable wherein adjustment of said camera varies the field of view of said camera;    detecting a target object in images acquired by said camera;    acquiring first, second and third images, each of said first, second and third images recording a different field of view;    communicating a first command to said camera selectively adjusting said camera;    communicating a second command to said camera selectively adjusting said camera; and    continuously adjusting said camera between acquisition of said first image and acquisition of said third image wherein said camera is adjusted in accordance with said first command during at least a portion of a first time interval between acquisition of said first image and acquisition of said second image and said camera is adjusted in accordance with said second command during at least a portion of a second time interval between acquisition of said second image and acquisition of said third image.    
     
     
         58 . The method of  claim 57  wherein said first and second commands selectively adjust at least one of a panning orientation of said camera, a tilt orientation of said camera, and a focal length of said camera.  
     
     
         59 . The method of  claim 57  wherein said first and second commands selectively adjust said camera at a selectively variable adjustment rate in the adjustment of at least one of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         60 . The method of  claim 57  wherein said first and second commands select a variable adjustment rate for each of a panning orientation of said camera and a tilt orientation of said camera.  
     
     
         61 . The method of  claim 60  wherein at least one of the variable adjustment rates are selected as a function of the velocity of the target object.  
     
     
         62 . A video tracking system comprising: 
 a video camera having a selectively adjustable focal length; and    at least one processor operably coupled to said camera wherein said processor receives video images acquired by said camera and selectively adjusts the focal length of said camera; said processor programmed to detect a moving target object in said video images and adjust the focal length of said camera as a function of the distance of the target object from the camera.    
     
     
         63 . The video tracking system of  claim 62  wherein said camera has a selectively adjustable panning orientation and a selectively adjustable tilting orientation; said processor adjusting said panning orientation and said tilting orientation to maintain the target object centered in the video images and wherein said processor selectively adjusts the focal length of said camera as a function of the tilt angle.  
     
     
         64 . A method of automatically tracking a target object with a video camera, said method comprising: 
 providing a video camera having a selectively adjustable focal length; and    adjusting the focal length of the camera as a function of the distance of the target object from the camera.    
     
     
         65 . The method of  claim 64  wherein the camera has a selectively adjustable panning orientation and a selectively adjustable tilting orientation and said method further includes adjusting the panning and tilting orientation of the camera to track the target object and selectively adjusting the focal length of the camera as a function of the tilt angle of camera.