Projection method of three-dimensional imaging

• US 9,575,016 B2
• Filed: 10/07/2015
• Issued: 02/21/2017
• Est. Priority Date: 10/30/2014
• Status: Active Grant

• Current Assignee: Institute Of Nuclear Energy Research Atomic Energy Council Executive Yuan
• Original Assignee: Institute Of Nuclear Energy Research Atomic Energy Council Executive Yuan
• Inventors: Jan, Meei-Ling, Tseng, Fan-Pin
• Primary Examiner(s): Lu, Tom Y
• Application Number:
  US14/877,470
• Publication Number:
  US 20160123900A1
• Time in Patent Office: 503 Days
• Field of Search: 382/128, 382/131, 382/133, 382/154
• US Class Current: 1/1
• CPC Class Codes: G01N 23/04 and forming images of the material
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G06T 11/005 Specific pre-processing for tomographic reconstruction, e.g. calibration, source positioning, rebinning, scatter correction, retrospective gating
• CPC Class Codes: G06T 2211/416 Exact reconstruction
• CPC Class Codes: G06T 2211/424 Iterative

Abstract

A projection method of three-dimensional imaging includes the steps of respectively projecting a radiation field emitted from a radiation source with respect to one specific detector of a plurality of detectors and a three-dimensional sub-voxel onto two two-dimensional planes; rotating the specific detector to one specific axis of the two dimensional plane; performing a calculation for obtaining a sub-geometric factor corresponding to each specific detector and each voxel; and, finally, forming a geometric factor by combining each sub-geometric factor defined by each detector and each voxel.

Claims

1. A projection method of three-dimensional imaging, comprising the steps of:

(a) providing a light source, wherein the light source is to generate a radiation field for being projected onto a detecting module, which includes a plurality of detectors arranged in an array pattern;

(b) piling between the light source and the detecting module a plurality of three-dimensional sub-voxels to form a voxel in a form of 3D matrix;

(c) defining a sub radiation field between each of the detectors that have detected the radiation field and the light source;

(d) basing on each of the three-dimensional sub-voxels in the sub radiation field with respect to each of the detectors to perform a calculation so as to obtain a sub-geometric factor, the calculation further comprising the steps of;

(d1) projecting each of the detectors, the sub radiation field respective to each of the detectors, and the plurality of three-dimensional sub-voxels onto a first detection plane and a second detection plane, respectively, so that each of the detectors, the sub radiation field respective to each of the detectors, and the plurality of three-dimensional sub-voxels form correspondingly a plane detector, a plane radiation field and a plurality of 1D arrays in parallel to further form a two-dimensional plane on the first detection plane and the second detection plane, respectively;

wherein each of the 1D arrays has a plurality of grids, and wherein the first detection plane is expanded by a first axis and a second axis and the second detection plane is expanded by the first axis and a third axis;

(d2) rotating the plane detector to the first axis of the first detection plane and the first axis of the second detection plane, respectively, so as to generate a varied coordinate between the plane detector and the plurality of grids;

(d3) basing on the varied coordinate to calculate a corresponding geometric ratio value for each of the grids of the plane radiation field with respect to each of the plane detectors to occupy the first detection plane and the second detection plane, respectively; and

(d4) multiplying the two geometric ratio values of each said grid with respect to the first detection plane and the second detection plane so as to obtain the sub-geometric factor of the three-dimensional sub-voxel with respect to each said detector; and

(e) collecting all the sub-geometric factors of the three-dimensional sub-voxels with respect to the individual detectors in the sub radiation field to form a geometric factor matrix.

2. The projection method of three-dimensional imaging of claim 1, wherein the step (d3) further includes the steps of:

(d31) locating a plurality of radiation-field intersection points along a calculation pathway for the plane radiation fields with respect to the individual plane detectors on the first detection plane and the second detection plane, respectively, wherein the calculation pathways on the first detection plane and the second detection plane are the second axis of the first detection plane and the third axis of the second detection plane, respectively;

(d32) basing on the varied coordinate to locate respectively a plurality of specific intersection points of each individual grid on the calculation pathway with respect to the first detection plane and the second detection plane; and

(d33) performing a calculation for comparing coordinates of a plurality of radiation-field intersection points and coordinates of a plurality of specific intersection points, so as to determine the corresponding geometric ratio value of the individual plane radiation field of each said grid on the calculation pathway with respect to each corresponding plane detector.

3. The projection method of three-dimensional imaging of claim 2, after the step (d31) and prior to the step (d32), further including the steps of:

(d311) basing on the varied coordinate to calculate proportionally an occupied length of the plane radiation field on the calculation pathway; and

(d322) basing on the occupied length of the plane radiation field on the calculation pathway to derive the coordinates of the radiation-field intersection points.

4. The projection method of three-dimensional imaging of claim 3, wherein the step (d311) further includes the steps of:

(d3111) determining a corresponding first district within the plane radiation field with respect to each of the plane detectors;

(d3112) determining a corresponding second district on the calculation pathway within the plane radiation field with respect to each of the plane detectors; and

(d3113) basing on the varied coordinate to obtain a ratio of the first district to the second district so as to derive the occupied length of the plane radiation field on the calculation pathway.

5. The projection method of three-dimensional imaging of claim 2, prior to performing the step (d33), further including the steps of:

(d33a) determining a boundary distance;

(d33b) selecting a selected distance on the calculation pathway, wherein the selected distance is larger than the boundary distance; and

(d33c) within a range of the calculation pathway defined by having the grid as a center and the selected distance as a radius, determining if any specific intersection point is located in the plane radiation field.

6. The projection method of three-dimensional imaging of claim 2, further including a step of:

multiplying the sub-geometric factor by a weighting factor.

7. The projection method of three-dimensional imaging of claim 1, after the step (d4), further including the steps of:

(d41) calculating a number of the grids parallel to the first axis on the first detection plane and the second detection plane, respectively; and

(d42) multiplying the sub-geometric factor by a normalized factor, wherein the normalized factor is the ratio of a parameter 1 to the number of the grids.

8. The projection method of three-dimensional imaging of claim 1, wherein the light source further undergoes a rotating movement.

9. The projection method of three-dimensional imaging of claim 1, wherein the detecting module is one of a tomosynthesis and a computed tomography.