Method and system for creating task-dependent three-dimensional images

Abstract

A system and method for producing three-dimensional representations of an object. A first series of projected images of the selected object is recorded in a first projection plane and a second series of projected images of the selected object is recorded in a second projection plane. The first and the second series of projected images are rendered at a common magnification. The first set of projected images is then integrated into a first three-dimensional volume and the second set of projected images is integrated into a second three-dimensional volume. The three-dimensional representation of the object is then produced by combining one projected image from the first set of projected images with one projected image from the second set of projected images. Alternatively, the three-dimensional representation is produced by merging the first three-dimensional volume with the second three-dimensional volume.

1 . A system for synthesizing an image of an object at a selected slice position through the selected object comprising: 
 a. an identifiable fiducial reference located at a fixed position relative to the selected object, the fiducial reference providing constraint for a number of degrees of freedom correlated to a number of degrees of freedom of the system;    b. a source of radiation for irradiating the selected object and the fiducial reference;    c. a recording medium for recording a first set and a second set of projected images of the fiducial reference and a region of interest of the selected object; and    d. an image synthesizer for determining overlapping regions of the projected images by identifying fiducial reference points common to the overlapping regions and for bringing the first and second sets of projected images into alignment based on the identified reference points to reconstruct a tomographic slice from the object images;    whereby the fiducial reference, the source of radiation, and the recording medium are arbitrarily positioned relative to one another.    
   
   
       2 . The system according to  claim 1 , wherein the recording medium includes a CCD device.  
   
   
       3 . The system according to  claim 1 , wherein the fiducial reference comprises at least five identifiable reference markers in a fixed geometry relative to each other.  
   
   
       4 . The system according to  claim 3 , wherein at least four of the reference markers are co-planar.  
   
   
       5 . The system according to  claim 4 , wherein a maximum of any two of the four co-planar reference markers are co-linear.  
   
   
       6 . The system according to  claim 5 , wherein a fifth reference marker is not co-planar with the four co-planar reference markers.  
   
   
       7 . The system according to  claim 1 , wherein the source of radiation comprises an electron source for irradiating the selected object and the fiducial reference with electrons.  
   
   
       8 . The system according to  claim 1 , wherein the source of radiation comprises a visible light source for irradiating the selected object and the fiducial reference, and the recording medium comprises a photographic recording medium for recording photographic images of the selected object and fiducial reference.  
   
   
       9 . The system according to  claim 8 , wherein the source of radiation and the recording medium comprise a video camera.  
   
   
       10 . A system according to  claim 1 , wherein the fiducial reference comprises a rectangular parallelepiped having at least six reference markers, each face of the parallelepiped comprising at least one reference marker, the parallelepiped comprising at least two bars disposed at intersecting edges of the parallelepiped such that the bars provide at least one additional reference marker disposed at the intersection of the bars.  
   
   
       11 . A system for synthesizing an image of an object according to  claim 1 , wherein the fiducial reference comprises at least two identifiable reference markers in a fixed geometry relative to each other.  
   
   
       12 . A system for synthesizing an image of an object according to  claim 11 , wherein the the markers differ in opacity from one another.  
   
   
       13 . A system for synthesizing an image of an object according to  claim 1 , wherein the image synthesizer is adapted to extrapolate registration and calibration of the sets of projected images.  
   
   
       14 . A method for synthesizing an image slice through a selected object at a selected slice position through the object from a plurality of projected images of the object comprising the steps of: 
 a. providing a fiducial reference to provide a total number of degrees of freedom associated therewith greater or equal to the total number of degrees of freedom of the system;    b. recording projected images of a region of interest of the selected object and the fiducial reference on a recording means at different arbitrary relative positions between (1) a source of radiation, (2) the selected object and fiducial reference, and (3) the recording means; and    c. synthesizing an image slice of the selected object at a selected slice position by determining overlapping regions of the projected images by identifying fiducial reference points common to the overlapping regions and bringing the first and second sets of projected images into alignment based on the identified reference points.    
   
   
       15 . A method for synthesizing an image slice according to  claim 14 , comprising the step of extrapolating registration and calibration of the sets of projected images.  
   
   
       16 . A method according to  claim 14 , wherein the region of interest comprises a subvolume in which the magnification of the projected images is substantially constant.  
   
   
       17 . A method according to  claim 14 , wherein the fiducial reference comprises identifiable reference markers.  
   
   
       18 . A method according to  claim 17 , comprising the steps of associating each reference marker projected image with the corresponding reference marker and measuring the position and size of each reference marker image.  
   
   
       19 . A method according to  claim 18 , comprising the step of determining the magnification of the projected image of the reference marker.  
   
   
       20 . A method according to  claim 19 , wherein the image of the reference marker comprises a minor diameter and the step of determining the magnification uses the minor diameter to determine the magnification.  
   
   
       21 . A method according to  claim 19 , comprising the step of generating a projected transformation matrix.  
   
   
       22 . A method according to  claim 21 , wherein the step of generating the projected transformation matrix comprises mapping the position of the reference marker image in the projected image onto a corresponding position of the reference marker in a virtual projection plane.  
   
   
       23 . A method according to  claim 22 , comprising the steps of synthesizing a plurality of image slices and generating a three-dimensional representation of the selected object from the plurality of image slices.