Data processing device for computed tomography system
First Claim
1. An apparatus for reconstructing a two-dimensional image of an object lying in a plane, said apparatus comprising:
- (a) radiation source means for supplying a fan-shaped radiation to the object;
(b) detector means, positioned opposite said radiation source means through the object so as to lie in the plane, for detecting radiation such as X-rays in the plane;
(c) means for effecting a relative rotation between the object and said radiation source means about an axis of rotation; and
(d) image reconstruction means, connected to said detector means, for performing a specific calculation for image reconstruction, said image reconstruction means comprising(1) first processing means for successively generating N sets of back-projection matrix data based on outputs derived from said detector means at N angles of said rotation, where N represents a positive integer not less than 2,(2) second processing means, connected to said first processing means, for summing successive n sets of back-projection matrix data, among N sets of back-projection matrix data, and for successively providing summed data, where n is a positive integer not less than 2,(3) image memory means for temporarily storing calculation result data, and(4) third processing means, connected to said second processing means and said memory means, for successively receiving the summed data for n times (n=N/K, where k is a positive integer not less than
2) and sequentially adding said summed data in such a manner that said third processing means repetitiously performs an arithmetic operation of adding that summed data which is currently supplied to said third processing means to that summed data which is currently stored in said memory means and replacing said summed data stored in said memory means with new summed data resulting from said addition by said third processing means, thereby finally permitting said memory means to a store a final value of said N sets of back-projection matrix data, whereby the number of write-operations of said memory means, which are required to attain said N sets of back-projection matrix data, is reduced substantially to N/n so that a back-projection time necessary for image reconstruction is reduced, accordingly.
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Abstract
A data processing device applied to a computed tomography system which examines a living body utilizing radiation of X-rays is disclosed. The X-rays which have penetrated the living body are converted into electric signals in a detecting section. The electric signals are acquired and converted from an analog form into a digital form in a data acquisition section, and then supplied to a matrix data-generating section included in the data processing device. By this matrix data-generating section are generated matrix data which correspond to a plurality of projection data. These matrix data are supplied to a partial sum-producing section. The partial sums respectively corresponding to groups of the matrix data are calculated in this partial sum-producing section and then supplied to an accumulation section. In this accumulation section, the final value corresponding to the total sum of the matrix data is calculated, whereby the calculation for image reconstruction is performed.
31 Citations
15 Claims
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1. An apparatus for reconstructing a two-dimensional image of an object lying in a plane, said apparatus comprising:
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(a) radiation source means for supplying a fan-shaped radiation to the object; (b) detector means, positioned opposite said radiation source means through the object so as to lie in the plane, for detecting radiation such as X-rays in the plane; (c) means for effecting a relative rotation between the object and said radiation source means about an axis of rotation; and
(d) image reconstruction means, connected to said detector means, for performing a specific calculation for image reconstruction, said image reconstruction means comprising(1) first processing means for successively generating N sets of back-projection matrix data based on outputs derived from said detector means at N angles of said rotation, where N represents a positive integer not less than 2, (2) second processing means, connected to said first processing means, for summing successive n sets of back-projection matrix data, among N sets of back-projection matrix data, and for successively providing summed data, where n is a positive integer not less than 2, (3) image memory means for temporarily storing calculation result data, and (4) third processing means, connected to said second processing means and said memory means, for successively receiving the summed data for n times (n=N/K, where k is a positive integer not less than
2) and sequentially adding said summed data in such a manner that said third processing means repetitiously performs an arithmetic operation of adding that summed data which is currently supplied to said third processing means to that summed data which is currently stored in said memory means and replacing said summed data stored in said memory means with new summed data resulting from said addition by said third processing means, thereby finally permitting said memory means to a store a final value of said N sets of back-projection matrix data, whereby the number of write-operations of said memory means, which are required to attain said N sets of back-projection matrix data, is reduced substantially to N/n so that a back-projection time necessary for image reconstruction is reduced, accordingly. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus for reconstructing a two-dimensional image created by radiation of a fan-shaped beam irradiated from a plurality of angles in an object to be examined and through said object onto detector elements adjacent to each other at which a multiplicity of signals are received at said plurality of angles, said apparatus comprising:
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first processing means for generating back-projection data based on the signals received by the detector elements at said angles; second processing means for summing a set of successive back-projection data provided from said first processing means and for generating a summed data of the set of successive back-projection data; image memory means having a plurality of memory locations corresponding to said image, for storing values representative of said image; third processing means for adding the summed data provided from said second processing means to that value which results from previously summed data and is stored in said image memory means and for storing the added data in place of the value of said previously summed data for back-projection. - View Dependent Claims (15)
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Specification