System and method for focusing imaging devices

Abstract

A system and method for automatically focusing imaging devices on an imaging set employs at least one tracker and two or more tracking markers, each tracking marker having an identification means and a tracking pattern. The tracking markers are configured for attaching to the imaging devices and to corresponding subjects to be imaged. A tracker gathers image information of the imaging set and provides it to a controller, which compares the image information to predetermined stored information about the tracking patterns of the various tracking markers. The tracking markers are identified and their three-dimensional positions determined. The distances between the imaging devices and the subjects are determined and the distances between the imaging devices and the subjects are calculated. This provides the focus setting information for communication to the imaging devices. The tracking patterns may have no rotational symmetry, allowing the orientation of subjects to be determined.

What is claimed is: 
     
         1 . A system for automatically adjusting a focus setting of at least one imaging device on an imaging set, the system comprising:
 two or more tracking markers, each tracking marker comprising an identification means and a tracking pattern, the two or more tracking markers configured for attaching to the at least one imaging device and to corresponding one or more subjects to be imaged on the imaging set by the at least one imaging device;   a first tracker disposed proximate the imaging set to gather first image information of the imaging set, the first tracker having a field of view including the at least one imaging device and the one or more subjects;   a controller configured for receiving the first image information from the first tracker and for communicating to the at least one imaging device control signals for the adjusting of focus settings for the at least one imaging device based on distances between the at least one imaging device and the one or more subjects; and   a database comprising predetermined information about the two or more identities and two or more tracking patterns of the corresponding two or more tracking markers.   
     
     
         2 . The system of  claim 1 , wherein the controller is further configured for communicating the control signals based on the distances between the at least one imaging device and the one or more subjects. 
     
     
         3 . The system of  claim 2 , wherein the controller is further configured for comparing the first image information with the predetermined information; identifying from the first image information the two or more tracking markers; determining the three-dimensional locations of the two or more tracking markers; and determining distances between the at least one imaging device and the one or more subjects. 
     
     
         4 . The system of  claim 3 , wherein the one or more subjects comprise two or more subjects and the controller is further configured for determining a required depth of focus from the distances between the at least one imaging device and the two or more subjects, and for communicating the control signals based on the required depth of focus for the at least one imaging device. 
     
     
         5 . The system of  claim 1 , wherein the tracking pattern of each of the two or more tracking markers has no rotational symmetry. 
     
     
         6 . The system of  claim 1 , wherein the tracking pattern of each of the two or more tracking markers comprises a plurality of contrasting portions. 
     
     
         7 . The system of  claim 6 , wherein at least one of the contrasting portions has a perimeter comprising a mathematically describable curved section. 
     
     
         8 . The system of  claim 7 , wherein the perimeter of the at least one contrasting portion comprises a conic section. 
     
     
         9 . The system of  claim 8 , wherein the conic section is one of an ellipse and a circle. 
     
     
         10 . The system of  claim 1 , additionally comprising at least one further tracker disposed proximate the imaging set to gather further image information of the imaging set, the at least one further tracker having a field of view including the two or more tracking markers; and wherein the controller is further configured for receiving the further image information from the at least one further tracker and for communicating to the at least one imaging device control signals for the adjusting of focus settings for the at least one imaging device based on distances between the at least one imaging device and the one or more subjects. 
     
     
         11 . A method for automatically adjusting a focus setting of an imaging device on an imaging set, the method comprising:
 attaching one or more tracking markers to corresponding one or more subjects on the imaging set, each tracking marker comprising an identification means and a tracking pattern;   disposing the imaging device to have a field of view to include the one or more tracking markers on the imaging set;   obtaining from the imaging device first image information of the imaging set;   determining focus settings for the imaging device based on the first image information and predetermined information in a database about one or more identities and one or more tracking patterns corresponding to the one or more tracking markers; and   adjusting the imaging device based on the focus settings.   
     
     
         12 . The method of  claim 11 , wherein the determining focus settings for the imaging device comprises:
 identifying from the first image information the one or more tracking markers;   determining the three-dimensional locations of the one or more tracking markers;   determining distances between the imaging device and the one or more subjects; and   determining the focus settings for the imaging device based on the distances between the imaging device and the one or more subjects   
     
     
         13 . The method of  claim 12 , further comprising:
 determining a required depth of focus for the imaging device from the distances between the imaging device and the one or more subjects, and   communicating to the imaging device the control signals based on the required depth of focus for the imaging device.   
     
     
         14 . The method of  claim 12 , wherein each tracking pattern comprises at least one contrasting portion and the determining the three-dimensional locations of the one or more tracking markers comprises determining a contrasting portion reference point for each of the one or more tracking markers. 
     
     
         15 . The method of  claim 14 , wherein the at least one contrasting portion has a perimeter that comprises a mathematically describable curved section and determining a contrasting portion reference point for each of the one or more tracking markers comprises determining a contrasting portion reference point relative to the mathematically describable curved section. 
     
     
         16 . The method of  claim 15 , wherein the mathematically describable curved section is a circle, and determining a contrasting portion reference point comprises determining a centre of the circle. 
     
     
         17 . The method of  claim 15 , wherein the mathematically describable curved section is an ellipse, and determining a contrasting portion reference point comprises determining a centre of the ellipse. 
     
     
         18 . The method of  claim 11 , further comprising:
 disposing at least one tracker proximate the imaging set;   configuring the at least one tracker to have a field of view including the one or more tracking markers;   gathering from the at least one tracker further image information of the imaging set;   determining further focus settings for the imaging device based on the further image information and predetermined information in a database about the one or more identities and the one or more tracking patterns corresponding to the one or more tracking markers; and   adjusting the imaging device based on the further focus settings.