Apparatus and method for density discrimination of objects in computed tomography data using multiple density ranges
First Claim
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1. A method of identifying an object represented computed tomography (CT) data for a region comprising:
- identifying a plurality of volume elements for the region in the CT data, each volume element being associated with a density value;
identifying a first density range and a second density range;
for each of the plurality of volume elements, comparing the density value of the volume element with at least one of the density ranges;
if the density value of the volume element is within one of the density ranges, labeling the volume element as being associated with an object of interest; and
for each volume element labeled as being associated with an object of interest, (i) computing a difference between the density value of the volume element and the density value of a neighboring volume element, and (ii) if the difference between the density value of the volume element and the density value of the neighboring volume element is below a predetermined difference threshold, combining the volume element and the neighboring volume element into a single object.
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Abstract
A method and apparatus for detecting and classifying objects in computed tomography (CT) data are disclosed. A connectivity process can be applied to voxels in the data to combine them into objects. A dilation function can then be performed on the eroded object to replace surface voxels removed by erosion. A corrected mass using the mean eroded density of the object can be computed and compared to mass thresholds to classify the object as to whether it poses a threat. Multiple mass thresholds can be used, each of which is associated with a particular density range based on the density of an expected threat object.
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Citations
45 Claims
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1. A method of identifying an object represented computed tomography (CT) data for a region comprising:
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identifying a plurality of volume elements for the region in the CT data, each volume element being associated with a density value; identifying a first density range and a second density range; for each of the plurality of volume elements, comparing the density value of the volume element with at least one of the density ranges; if the density value of the volume element is within one of the density ranges, labeling the volume element as being associated with an object of interest; and for each volume element labeled as being associated with an object of interest, (i) computing a difference between the density value of the volume element and the density value of a neighboring volume element, and (ii) if the difference between the density value of the volume element and the density value of the neighboring volume element is below a predetermined difference threshold, combining the volume element and the neighboring volume element into a single object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An apparatus for identifying an object represented in computed tomography (CT) data for a region comprising:
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means for identifying a plurality of volume elements for the region in the CT data, each volume element being associated with a density value; means for identifying a first density range and a second density range; means for comparing the density value of the volume element with at least one of the density ranges; means for labeling the volume element as being associated with an object of interest if the density value of the volume element is within one of the density ranges; means for computing, for each volume element labeled as being associated with an object of interest, a difference between the density value of the volume element labeled as being associated with an object of interest and the density value of a neighboring volume element; and means for combining the volume element labeled as being associated with an object of interest and the neighboring volume element into a single object if the difference between the density value of the volume element labeled as being associated with an object of interest and the density value of the neighboring volume element is below a predetermined difference threshold. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A computed tomography (CT) scanning system for processing CT data for a region comprising:
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means for acquiring the CT data for the region; means for identifying a plurality of volume elements for the region in the CT data, each volume element being associated with a density value; means for identifying a first density range and a second density range; means for comparing the density value of the volume element with at least one of the density ranges; means for labeling the volume element as being associated with an object of interest if the density value of the volume element is within one of the density ranges means for computing, for each volume element labeled as being associated with an object of interest, a difference between the density value of the volume element labeled as being associated with an object of interest and the density value of a neighboring volume element; and means for combining the volume element labeled as being associated with an object of interest and the neighboring volume element into a single object if the difference between the density value of the volume element labeled as being associated with an object of interest and the density value of the neighboring volume element is below a predetermined difference threshold. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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Specification