Methods and apparatus for super resolution scanning for CBCT system and cone-beam image reconstruction
View Patent ↗Embodiments of methods and/or apparatus for 3-D volume image reconstruction of a subject, executed at least in part on a computer for use with a digital radiographic apparatus can obtain image data for 2-D projection images over a range of scan angles. For each of the plurality of projection images, an enhanced projection image can be generated. In one embodiment, through the application of a resolution increasing interpolator, a prescribed CBCT routine scanning mode with preset binning can increase a spatial resolution, Nyquist frequency or MTF.
1. A method for digital radiographic 3D volume image reconstruction of a subject, executed at least in part on a computer, comprising:
obtaining image data at a first binning mode for a plurality of 2D projection images over a range of scan angles;
generating, for each of the plurality of 2D projection images, an increased-spatial resolution projection image by:
(i) providing an image representation of a different corresponding object at a second higher spatial resolution binning mode;
(ii) determining an image data transformation for the first binning mode according to the image representation obtained at the second higher spatial resolution binning mode;
(iii) applying the image data transformation individually to the plurality of 2D projection images obtained at the first binning mode to generate the increased-spatial resolution plurality of 2D projection images; and
storing the increased-spatial resolution plurality of 2D projection images in a computer-accessible memory.
2. The method of claim 1 wherein the transformed plurality of 2D projection images comprises a higher modulation transfer function (MTF) than the first binning mode or the transformed plurality of 2D projection images comprise a higher Nyquist frequency than the first binning mode.
3. The method of claim 1 further comprising processing the plurality of increased-spatial projection images to reconstruct the 3D volume image reconstruction of the subject.
4. The method of claim 3 wherein the 3D volume image reconstruction comprises a higher MTF than the first binning mode or the 3D volume image reconstruction comprises a higher Nyquist frequency than the first binning mode.
5. The method of claim 1 wherein providing an image representation of a different corresponding object at a second higher spatial resolution binning mode comprises selecting a first high resolution image of the corresponding object, and wherein determining an image data transformation for the first binning mode comprises:
down-sampling the first high resolution image to the spatial resolution of the first binning mode;
iteratively interpolating the down-sampled image to obtain a second estimated high resolution image of the corresponding object; and
determining the image data transformation when an error between the first high resolution image and the second estimated high resolution image is less than a prescribed threshold.
6. The method of claim 1 wherein obtaining image data for a plurality of 2D projection images comprises obtaining image data from a cone-beam computerized tomography apparatus.
7. The method of claim 1 further comprising:
processing the plurality of increased-spatial projection images to reconstruct a 3D volume image reconstruction of the subject;
displaying the 3D volume image reconstruction; and
storing the 3D volume image reconstruction in the computer-accessible memory, wherein the 3D volume image reconstruction is a orthopedic medical image, a dental medical image, a pediatric medical image or generated by image data from a flat panel detector.
8. The method of claim 7 wherein processing the plurality of increased-spatial projection images comprises:
performing one or more of geometric correction, scatter correction, beam-hardening correction, and gain and offset correction on the plurality of 2D projection images;
performing a logarithmic operation on the increased-spatial resolution plurality of 2D projection images to obtain line integral data; and
performing a row-wise ramp linear filtering to the line integral data.
9. The method of claim 1 wherein the subject is a limb, an extremity, a weight bearing extremity or a portion of a dental arch.
10. The method of claim 1 wherein a plurality of image representations of the different corresponding object at the second higher spatial resolution binning mode are used to determine the image data transformation for the first binning mode for a single cone-beam computed tomography scan.
11. The method of claim 1 wherein the image data transformation is based on an examination type and x-ray radiation source exposure setting.
12. The method of claim 1 wherein the image data transformation is angularly independent.
13. The method of claim 1 wherein the image data transformation is provided by a neural network interpolator.
14. The method of claim 1 wherein the image data transformation is provided by a plurality of neural network interpolators.
15. A method for digital radiographic 3D volume image reconstruction of a subject, executed at least in part on a computer, comprising:
obtaining cone-beam computed tomography image data at a first binning mode for a plurality of 2D projection images over a range of scan angles;
generating, for each of the plurality of 2D projection images, an increased-spatial resolution projection image by:
(i) providing an image data transformation for the first binning mode according to image data from a second higher spatial resolution binning mode;
(ii) applying the image data transformation individually to the plurality of 2D projection images obtained at the first binning mode to generate the increased-spatial resolution plurality of 2D projection images; and
storing the increased-spatial resolution plurality of 2D projection images in a computer-accessible memory.
16. A digital radiography CBCT imaging system for digital radiographic 3D volume image reconstruction of a subject, comprising:
a DR detector to obtain a plurality of CBCT 2D projection images over a range of scan angles at a first binning mode;
a computational unit to generate, for each of the plurality of 2D projection images, an increased-spatial resolution projection image, the computational unit to select (i) an image data transformation for the first binning mode according to image data from a second higher spatial resolution binning mode, and (ii) apply the image data transformation individually to the plurality of 2D projection images obtained at the first binning mode to generate the increased-spatial resolution plurality of 2D projection images; and
a processor to store the increased-spatial resolution plurality of 2D projection images in a computer-readable memory.
17. The digital radiography CBCT imaging system of claim 16 , where the computational unit is a neural network interpolator.