Analogic Corporation

Christopher C Ruth

Carl R Crawford

Eric M Bailey

David A Schafer

Hans J Weedon

Bernard M Gordon

John M Dobbs

Ruvin Deych

Steven Neil Urchuk

Gregory L Larson

Iouri Bachilov

Alexander I Greenberg

A method and apparatus for performing CT scans of baggage being carried or loaded onto commercial aircraft are described. The CT baggage scanner of the invention includes numerous features which provide the system with high baggage throughput on the order of seven hundred bags per hour as well as improved image quality and accurate target detection. In one aspect, the scanner includes an adaptive image reconstruction window which identifies data collected from the field of view that are not related to the baggage being scanned. These unrelated data are excluded from the image reconstruction process, resulting in greatly reduced reconstruction time and increased baggage throughput. The invention also includes the capability of performing calibration &ldquo;air scans&rdquo; with objects such as the system conveyor in the field of view. Data gathered during the calibration scan are applied to a threshold, and data exceeding the threshold are assumed to be from X-rays that are unobstructed by objects in the field of view and are therefore used to perform the air calibration. The baggage scanner can also analyze scan data to identify shapes of objects, particularly, objects formed in the shape of a sheet. This greatly improves the ability of the system to detect sheet explosives. The system also compensates for detector dark currents and provides dark current offsets which can be dependent upon detector temperature.

Computed tomography scanning apparatus and method using adaptive reconstruction window

A method and apparatus for performing CT scans of baggage being carried or loaded onto commercial aircraft are described. The CT baggage scanner of the invention includes numerous features which provide the system with high baggage throughput on the order of seven hundred bags per hour as well as improved image quality and accurate target detection. In one aspect, the scanner includes an adaptive image reconstruction window which identifies data collected from the field of view that are not related to the baggage being scanned. These unrelated data are excluded from the image reconstruction process, resulting in greatly reduced reconstruction time and increased baggage throughput. The invention also includes the capability of performing calibration 'air scans' with objects such as the system conveyor in the field of view. Data gathered during the calibration scan are applied to a threshold, and data exceeding the threshold are assumed to be from X-rays that are unobstructed by objects in the field of view and are therefore used to perform the air calibration. The baggage scanner can also analyze scan data to identify shapes of objects, particularly, objects formed in the shape of a sheet. This greatly improves the ability of the system to detect sheet explosives. The system also compensates for detector dark currents and provides dark current offsets which can be dependent upon detector temperature.

Computed tomography scanning apparatus and method with temperature

Air calibration scan for computed tomography scanner with obstructing

A nutating slice CT image reconstruction apparatus and method generates a set of projection data using helical cone-beam scanning. The three-dimensional projection data is used to reconstruct a series of planar image slices. The slices are selected such that they define a tilt angle and a rotation angle with respect to the longitudinal axes of the object being scanned. Successive slices have equal tilt angles but changing rotation angles such that normal axes of successive slices define a nutation and precession about the longitudinal axis of the object. Projection data for the tilted slices are formed of selected one-dimensional fan-beam data. As such, the projection data can be applied to conventional two-dimensional reconstruction approaches to generate an image. The projection data can also be used to generate two-dimensional projection images at one or more stationary projection angles through an object being scanned. The nutation or tilt of image volume elements can be compensated for to provide a more accurate image and more accurate target assessment such as accurate total mass determination. A parallel processing architecture can be used to generate and process the nutated slices with improved efficiency.

Computed tomography scanning target detection using non-parallel slices

Computed tomography scanning target detection using target surface

Parallel processing architecture for computed tomography scanning system

Computed tomography scanning apparatus and method for generating

A method and apparatus for halfscan reconstruction in a CT scanning system using an asymmetric detector system are described. In halfscan asymmetric (HSA) reconstruction, a halfscan reconstruction approach is used for data acquired by the symmetric portion of the array, and a fullscan reconstruction approach is used to reconstruct data acquired by the asymmetric portion of the array. When scanning oversized subjects which extend beyond the symmetric field of view of the array, a halfscan reconstruction approach is used which applies a zero weighting to data acquired by the asymmetric portion of the array and ramps data acquired by the asymmetric portion to zero.

Apparatus and method for computed tomography scanning using halfscan

A system for and method of generating a reconstructed tomographic image is described using an asymmetric detector array during a helical scan. An improved helical weighting system applies a helical halfscan technique to data collected by a symmetric portion of an asymmetric detector system and applies a helical fullscan technique to data collected by an asymmetric portion of the asymmetric detector system. The preferred system comprises an equi-angle interpolator, a streak artifact suppression filter, and an isocenter interpolator that preserve the distinction between even and odd data points in parallel beam projection data.

Method and apparatus for helical computed tomography scanning with

A nutating slice CT image reconstruction apparatus and method generates a set of projection data using helical cone-beam scanning. The three-dimensional projection data is used to reconstruct a series of planar image slices. The slices are selected such that they define a tilt angle and a rotation angle with respect to the longitudinal axes of the object being scanned. Successive slices have equal tilt angles but changing rotation angles such that normal axes of successive slices define a nutation and precession about the longitudinal axis of the object. Projection data for the tilted slices are formed of selected one-dimensional fan-beam data. As such, the projection data can be applied to conventional two-dimensional reconstruction approaches to generate an image.

Nutating slice CT image reconstruction apparatus and method

The disclosed CT scanner includes a tomography system for generating data during a scan. The tomography system includes a detector characterized by at least one afterglow amplitude and at least one afterglow time constant, and a sampling device for generating a plurality of samples x.sub.i for all i from zero to MAX minus one of the detector output signal. The scanner also includes a set of N sub-processors for processing the samples x.sub.i, each of the sub-processors being represented by a unique integer q selected from zero to N minus one and receiving only the samples X.sub.iN+q. Each sub-processor includes a device for generating a compensated signal according to a function of at least a portion of the received samples and parameters representative of the afterglow amplitude and the afterglow time constant.

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Danvers, MA, United States of America

Christopher C Ruth