Abstract: A method and apparatus compress projection data and store the compressed projection data in a rotatable part that is mounted for rotation within a stationary part. The data acquisition source, compressor and storage device are connected to the rotatable part. The compressor compresses projection data samples provided by the data acquisition source to form compressed packets. The compressed packets are stored in the storage device, for example one or more solid state drives mounted on the rotatable part. A data access array contains information related to the location of the stored compressed packets. Compressed packets are retrieved and transferred across the interface to the stationary part. A decompressor at the stationary part decompresses the received compressed packets to form decompressed samples of the corresponding projection data. This abstract does not limit the scope of the invention as described in the claims.

Abstract: A computed tomography system has a stationary part, a rotatable part mounted for rotation around an object to be examined and an interface between the stationary part and the rotatable part. The rotatable part includes an x-ray source, a sensor array for detecting x-rays passing through the object to produce projection data samples, a compressor that compresses the projection data samples and a storage device that stores the compressed samples. The storage device on the rotatable part can include one or more solid state drives. For image reconstruction, the compressed samples are retrieved from the storage device, transferred across the interface to the stationary part. A decompressor at the stationary part decompresses the received compressed samples and provides decompressed samples to the image reconstruction processor. This abstract does not limit the scope of the invention as described in the claims.

Abstract: A method of and a system for automatic object display of volumetric CT data for fast on-screen threat resolution are disclosed, wherein the CT data includes a CT image in a single energy CT scanner, or a CT image and a Z image in a multi-energy CT scanner, and a label image defining each object as a plurality of voxels of the volumetric CT data. The method comprises generating volumetric CT image data corresponding to a scanned bag; performing automatic threat detection to generate a label image; processing the volumetric CT data and the label image to obtain visualization parameters for each object; automatically generating display images for each object using corresponding visualization parameters; and displaying the generated display images for on-screen threat resolution.

Abstract: A method of and a system for identifying objects using local distribution features from multi-energy CT images are provided. The multi-energy CT images include a CT image, which approximates density measurements of scanned objects, and a Z image, which approximates effective atomic number measurements of scanned objects. The local distribution features are first and second order statistics of the local distributions of the density and atomic number measurements of different portions of a segmented object. The local distributions are the magnitude images of the first order derivative of the CT image and the Z image. Each segmented object is also divided into different portions to provide geometrical information for discrimination.

Abstract: A method and apparatus compress projection data and store the compressed projection data in a rotatable part that is mounted for rotation within a stationary part. The data acquisition source, compressor and storage device are connected to the rotatable part. The compressor compresses projection data samples provided by the data acquisition source to form compressed packets. The compressed packets are stored in the storage device, for example one or more solid state drives mounted on the rotatable part. A data access array contains information related to the location of the stored compressed packets. Compressed packets are retrieved and transferred across the interface to the stationary part. A decompressor at the stationary part decompresses the received compressed packets to form decompressed samples of the corresponding projection data. This abstract does not limit the scope of the invention as described in the claims.

Abstract: A computed tomography system has a stationary part, a rotatable part mounted for rotation around an object to be examined and an interface between the stationary part and the rotatable part. The rotatable part includes an x-ray source, a sensor array for detecting x-rays passing through the object to produce projection data samples, a compressor that compresses the projection data samples and a storage device that stores the compressed samples. The storage device on the rotatable part can include one or more solid state drives. For image reconstruction, the compressed samples are retrieved from the storage device, transferred across the interface to the stationary part. A decompressor at the stationary part decompresses the received compressed samples and provides decompressed samples to the image reconstruction processor. This abstract does not limit the scope of the invention as described in the claims.

Abstract: A method of and a system for variable pitch CT scanning for baggage screening and variable pitch image reconstruction are disclosed.

Abstract: A method of and a system for displaying volumetric multi-energy CT images are disclosed, wherein a CT image, a Z image, and a label image from an automatic explosive detection are provided, are disclosed. The method comprises generating an index image through a nonlinear transformation of the CT image, the Z image, and the label image, rotating and coloring the index image as desired, and rendering and displaying the rotated and colored image.

Abstract: A method of and a system for splitting a compound object using multi-energy CT data including a density and an atomic number measurements are provided. The method comprises: compound object detection; computing a two-dimensional DZ distribution of a compound object; identifying clusters within the DZ distribution; assigning a component label to each object voxel based on the DZ distribution clusters; and post-processing the set of voxels identified as belonging to each component.

Abstract: A method of and a system for identifying objects using histogram segment features from multi-energy CT images are provided. The multi-energy CT images include a CT image, which approximates density measurements of scanned objects, and a Z image, which approximates effective atomic number measurements of scanned objects. The method comprises: computing a density histogram for each potential threat object; smoothing the density histogram using a low-pass filter; identifying peaks in the smoothed density histogram; assigning a segment to each peak; computing histogram segment features for each segment; classifying each potential threat object into a threat or a non-threat using computed features.

Abstract: A method of and a system for variable pitch CT scanning for baggage screening and variable pitch image reconstruction are disclosed.

Abstract: A method of and a system for destreaking the photoelectric image in multi-energy computed tomography are provided, wherein the photoelectric projections are generated from the projection data acquired using at least two x-ray spectra for scanned objects; wherein a neighboring scheme is provided; the method comprises computing the statistics including mean and standard deviation using the neighboring scheme; calculating an upper limit and a lower limit from the computed statistics; detecting outliers in the photoelectric projections using the upper and lower limits; and replacing values of outliers using the upper or lower limit.

Abstract: A method of and a system for automatic object display of volumetric CT data for fast on-screen threat resolution are disclosed, wherein the CT data includes a CT image in a single energy CT scanner, or a CT image and a Z image in a multi-energy CT scanner, and a label image defining each object as a plurality of voxels of the volumetric CT data. The method comprises generating volumetric CT image data corresponding to a scanned bag; performing automatic threat detection to generate a label image; processing the volumetric CT data and the label image to obtain visualization parameters for each object; automatically generating display images for each object using corresponding visualization parameters; and displaying the generated display images for on-screen threat resolution.

Abstract: A method of and a system for detecting anomalies in projection images generated by CT scanners are provided. One type of anomaly of particular interest is bright or/and dark dots in projection images, which correspond to streak artifacts in the CT images. The method for detecting such bright or/and dark dots in projection images comprises: generating projection images; computing a CFAR distance map; computing a preliminary dot map; generating dot histograms; and detecting bright dots or/and dark dots based on the generated histograms.

Abstract: A method of and a system for extracting 3D bag images from continuously reconstructed 2D image slices are provided. The method detects the boundaries of baggage in the reconstructed images, and provides better flexibilities for threat detection and displaying. The method comprises detecting starting and ending slices using multiple slices, counting bag slices, splitting 3D bag images when maximum number of slices of a 3D bag image is reached, and creating overlapping slices for the split 3D bag images.

Abstract: A method of and a system for sharp object detection using computed tomography images are provided. The method comprises identifying voxels corresponding to individual objects; performing eigen-analysis and generating eigen-projection of an identified object; computing an axial concavity ratio of the identified object; computing a pointness measurement of the identified object; computing a flat area of the identified object; calculating a sharpness score of the identified object; and declaring the identified object as a threat if the sharpness score is greater than a pre-defined threshold.

Abstract: A method of and system for detecting threat objects represented in 3D CT data uses knowledge of one or more predefined shapes of the threat objects. An object represented by CT data for a region is identified. A two-dimensional projection of the object along a principal axis of the object is generated. A contour of the object boundary in the projection image is computed. A shape histogram is computed from the extracted contour. A difference measure between the extracted shape histogram and a set of pre-computed threat shape histograms is computed. A declaration of a threat object is made if the difference measure is less than a pre-defined threshold.

Abstract: A method of and a system for spectral correction in multi-energy computed tomography are provided to correct reconstructed images, including high-energy CT images and Z (effective atomic number) images, for spectral variations, which include time variations on a scanner due to HVPS drift and scanner to scanner variations due to the beamline component differences. The method uses a copper filter mounted on the detector array for tracking the spectral changes. The method comprises: generating copper ratios; computing working air tables; calculating scales and offsets; and correcting high-energy CT images and Z images using calculated scales and offsets. The method further includes an off-line calibration procedure to generate necessary parameters for the online correction.

Abstract: A method of performing bone correction on a computerized tomography (CT) image includes the steps of: A. generating a reconstructed CT image of a bone-containing portion of a patient's body, the reconstructed CT image including a bone region corresponding to the bone-containing portion; B. determining characteristics of the bone region of the image; and C. performing a bone correction procedure on the image, the bone correction procedure being performed at a gain that is determined based on the bone region characteristics.

Abstract: A method of decomposition of projection data is provided, wherein such projection data includes input projection data acquired using at least two x-ray spectra for a scanned object, including low energy projection data (PL) and high energy projection data (PH); the method comprises solving the projections PL and PH to determine a photoelectric line integral (Ap) component of attenuation and a Compton line integral (Ac) component of attenuation of the scanned object using a multi-step fitting procedure and constructing a Compton image Ic and a photoelectric image Ip from the Compton line integral and photoelectric line integral.