Motion artifacts reduction algorithm for two-exposure dual-energy radiography
First Claim
1. A method of improving image clarity of soft tissue and bone images decomposable from first and second energy images acquired by a digital radiography imaging system at different times, comprising the act of registering the first energy image to the second energy image using warping registration prior to decomposing the first and second energy images into the soft tissue and bone images.
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Abstract
The present technique provides a variety of processing schemes for decomposing soft tissue and bone images more accurately from low and high-energy images acquired from an imaging system, such as a dual-energy digital radiography system using flat-panel technology. In particular, a pre-decomposition process is provided for spatially matching, or registering, low and high-energy images using warping registration prior to dual energy image decomposition, which creates the soft tissue and bone images. Accordingly, the pre-decomposition process reduces motion artifacts between the low and high-energy images, thereby improving image clarity of the decomposed soft tissue and bone images.
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Citations
56 Claims
- 1. A method of improving image clarity of soft tissue and bone images decomposable from first and second energy images acquired by a digital radiography imaging system at different times, comprising the act of registering the first energy image to the second energy image using warping registration prior to decomposing the first and second energy images into the soft tissue and bone images.
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16. The method of claim l,comprising the act of decomposing the soft tissue and bone images from the first and second energy images after being registered.
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17. A method of reducing motion artifacts for two exposure dual energy radiography prior to decomposition of soft tissue and bone images, comprising:
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obtaining first and second energy images from a digital radiography imaging system over a time interval;
defining a maximum pixel range that any point in the first energy image is allowed to shift relative to the second energy image;
defining a spatial matrix for analyzing the first energy image;
decomposing a sub-image from the first and second energy images for each shift vector of a plurality of possible shift vectors for each spatial area of the spatial matrix;
computing a total edge strength for each possible shift vector within the maximum pixel range for each spatial area of the spatial matrix;
defining an area shift vector for each spatial area to be the shift vector that minimizes the total edge strength for the spatial area;
computing a pixel shift vector for each pixel within the first energy image by interpolation based on adjacent area shift vectors; and
registering the first energy image to the second energy image by warping the first energy image pixel-by-pixel using the pixel shift vectors. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
centering a maximum number of non-overlapping spatial areas on the first energy image; and
retaining a border around the spatial matrix to allow for the maximum pixel range.
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19. The method of claim 17, wherein the act of registering the first energy image to the second energy image comprises the act of spatially matching anatomical features in the first and second energy images.
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20. The method of claim 19, wherein the act of spatially matching anatomical features comprises the act of warping the first energy image relative to the second energy image.
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21. The method of claim 19, wherein the act of registering the first energy image to the second energy image comprises the act of substantially reducing motion variations between the first and second energy images.
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22. The method of claim 19, wherein the first and second energy images correspond to low-energy and high-energy image acquisition levels, respectively.
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23. The method of claim 19, wherein the first and second energy images correspond to first and second acquisition times over the time interval.
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24. The method of claim 19, wherein the first and second energy images are acquired from the digital radiography imaging system using flat-panel detector technology.
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25. The method of claim 19, comprising the act of decomposing soft tissue and bone images from the first and second energy images after being registered.
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26. A method of producing soft tissue and bone images of the desired anatomy of a patient, comprising the acts of:
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acquiring first and second images of the desired anatomy at different times using a digital radiography imaging system having flat-panel detector technology, wherein one image of the first and second images is acquired at a low-energy level and a remaining image of the first and second images is acquired at a high-energy level;
registering the first image to the second image using warping registration; and
decomposing soft tissue and bone images of the desired anatomy from the warpingly registered first and second images. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
decomposing a sub-image from the first and second images for each shift vector of a plurality of possible shift vectors for each spatial area of the spatial matrix; and
selecting one shift vector of the plurality of possible shift vectors for the spatial area that provides a minimum total edge strength for the spatial area.
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36. The method of claim 35,wherein the act of selecting one of the plurality of possible shift vectors comprises the acts of:
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limiting the plurality of possible shift vectors to a spatial search range;
computing a total edge strength for each of the plurality of possible shift vectors within the spatial search range; and
identifying the shift vector corresponding to the minimum total edge strength for the spatial area.
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37. The method of claim 33, wherein the act of computing shift vectors comprises the act of interpolating pixel shift vectors for each pixel of the first image from the area shift vectors of adjacent spatial areas of the spatial matrix.
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38. A computer program for processing image data acquired from a digital radiography imaging system, comprising:
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a tangible medium configured to support machine-readable code; and
machine-readable code supported on the medium and comprising a pre-decomposition warping-image-registration routine adapted to register first and second images prior to decomposition into soft tissue and bone images, wherein the first and second images are obtained from the digital radiography imaging system at different energy levels and different times. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
a sub-image decomposition routine adapted to decompose a soft tissue sub-image from the first and second images for each shift vector of a plurality of possible shift vectors for each spatial area of the spatial matrix; and
a selection routine adapted to select one shift vector of the plurality of possible shift vectors in a maximum shift search range for the spatial area that provides a minimum total edge strength for the spatial area.
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48. The computer program of claim 46, wherein the routine adapted to compute shift vectors comprises an interpolation routine adapted to interpolate pixel shift vectors for each pixel of the first image from the area shift vectors of adjacent spatial areas of the spatial matrix.
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49. A medical imaging system, comprising:
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a digital radiographic imaging system, comprising;
an x-ray device adapted to generate x-rays;
a collimator adapted to filter the x-rays in a desired anatomical region of a patient;
a flat-panel digital x-ray detector adapted to detect x-rays passing through the patient; and
dual-energy control circuitry adapted to acquire first and second images of the desired anatomical region at different energy levels over a time interval; and
an image processing system, comprising;
a pre-decomposition processing module adapted to register the first image to the second image using warping registration prior to decomposition; and
a dual-energy image decomposition module adapted to decompose soft tissue and bone images from the warpingly registered first and second images. - View Dependent Claims (50, 51, 52, 53, 54)
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55. A system for decomposing soft tissue and bone images from first and second energy images acquired by a digital radiography imaging system, comprising:
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means for warpingly registering the first energy image to the second energy image prior to image decomposition; and
means for decomposing the soft tissue and bone images from the first and second energy images. - View Dependent Claims (56)
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Specification