Method and apparatus for acquiring and processing only a necessary volume of radon data consistent with the overall shape of the object for efficient three dimensional image reconstruction

Claim 1

A method for reconstructing an image of a three dimensional object using an inverse Radon transform comprising the steps of: providing a mutually spaced irradiating beam source and a suitable array radiation detector in fixed relationship to one another; providing an object therebetween; irradiating said object within a field of view of said irradiating beam source; scanning said irradiated object along a preselected scanning trajectory to acquire a plurality of beam attenuation data at said array detector for a plurality of select source positions; organizing said beam attenuation data in the form of line integrals through said object for each of said plurality of source positions; determining from said beam attenuation data values representing planar integrals; organizing said planar integrals onto discrete polar grids on a predetermined plurality of planes coaxial with respect to a reference axis in Radon space; retaining on each said plane only evaluated planar integral values residing within a corresponding overall projected region of support of said object in Radon space in order to truncate each said polar grid to represent source beams actually penetrating said object; reconstructing a two dimensional projected image of said object onto each said plane from said retained integral values using parallel processing; organizing said plurality of two dimensional projection image data from said plurality of coaxial planes onto a plurality of planes slicing normally through said reference axis; and reconstructing two dimensional images on each planar slice using parallel processing to collectively provide a three dimensional reconstructed image of said object.

Claim 2

A method for reconstructing an image of a three dimensional object using an inverse Radon transform comprising the steps of: providing a mutually spaced irradiating beam source and a suitable array radiation detector in fixed relationship to one another; providing an object therebetween; irradiating said object within a field of view of said irradiating beam source; scanning said irradiated object along a preselected scanning trajectory to acquire a plurality of beam attenuation data at said array detector for a plurality of select source positions; organizing said beam attenuation data in the form of line integrals through said object for each of said plurality of source positions; determining from said beam attenuation data values representing planar integrals; organizing said planar integrals onto discrete polar grids on a predetermined plurality of planes coaxial with respect to a reference axis in Radon space; retaining on each said plane only evaluated planar integral values residing within a corresponding overall projected region of support of said object in Radon space in order to truncate each said polar grid to represent source beams actually penetrating said object; reconstructing a two dimensional projected image of said object onto each said plane from said retained integral values using parallel processing; organizing said plurality of two dimensional projection image data from said plurality of coaxial planes onto a plurality of planes slicing normally through said reference axis; and reconstructing two dimensional images on each planar slice using parallel processing to collectively provide a three dimensional reconstructed image of said object.

Claim 8

An apparatus for acquiring and processing only necessary Radon data for image reconstruction of a three dimensional object irradiated by a mutually spaced scanning source having improved computational efficiency, said apparatus comprising: a radiation beam source; array radiation detector means fixed with respect to said mutually spaced source; means for scanning said irradiated object along a preselected scanning trajectory by rotating said object relative to said mutually spaced source; detector means providing a plurality of source beam attenuation data corresponding to a plurality of source positions; means for acquiring said plurality of source beam attenuation data; means for selective computational processing reconstructing a three dimensional image of said object by a Radon inversion technique; said processing means selectively retaining a truncated Radon data set representing a subset ot source beam attenuation data wherein said beams actually penetrate the object; said processing means including means for suitably organizing and redistributing computational processing said truncated data set to provide faster parallel processing; a plurality of parallel processors for converting said plurality of source beam attenuation data into a corresponding plurality of planar integrals in Radon space subset therof being retained as said truncated Radon data see for computationally reconstructing only Radon data necessary for image reconstruction of said object alone; means for storing and retrieving computations; and means for displaying computations.

Claim 9

An apparatus for acquiring and processing only necessary Radon data for image reconstruction of a three dimensional object irradiated by a mutually spaced scanning source having improved computational efficiency, said apparatus comprising: a radiation beam source; array radiation detector means fixed with respect to said mutually spaced source; means for scanning said irradiated object along a preselected scanning trajectory by rotating said object relative to said mutually spaced source; detector means providing a plurality of source beam attenuation data corresponding to a plurality of source positions; means for acquiring said plurality of source beam attenuation data; means for selective computational processing reconstructing a three dimensional image of said object by a Radon inversion technique; said processing means selectively retaining a truncated Radon data set representing a subset ot source beam attenuation data wherein said beams actually penetrate the object; said processing means including means for suitably organizing and redistributing computational processing said truncated data set to provide faster parallel processing; a plurality of parallel processors for converting said plurality of source beam attenuation data into a corresponding plurality of planar integrals in Radon space subset therof being retained as said truncated Radon data see for computationally reconstructing only Radon data necessary for image reconstruction of said object alone; means for storing and retrieving computations; and means for displaying computations.