# US 10,119,923 B2 · Systems and methods for image reconstruction at high computed tomography pitch > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,119,923 B2 - Document ID: US10119923B2 - Status: Granted - Kind: B2 - Application number: 14/886,883 - Filed: 2015-10-19 - Published: 2017-04-20 - Granted: 2018-11-06 - Earliest claimed: 2015-10-19 - Assignees: L3 Security & Detection Systems, Inc. - Applicants: L3 Security & Detection Systems, Inc. - Inventors: Michael Schmitt; Andrew D. Foland; Boris Oreper - Web page: https://patentgrep.com/patent/US10119923B2 ## CPC - G01N 23/046: using tomography, e.g. computed tomography [CT] - G06T 12/20: Inverse problem, i.e. transformations from projection space into object space - G01N 2223/401: image processing - G01N 2223/408: display on monitor - G01N 2223/419: computed tomograph - G01N 2223/643: object on conveyor - G06T 2211/424: Iterative - G06T 2211/436: Limited angle - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract Methodologies, systems, apparatus, and non-transitory computer-readable media are described herein to facilitate acquisition of volumetric data and volumetric image reconstruction. An imaging system can be configured to transport an object at a speed relative to the scan path of an X-ray source such that insufficient measurement data is collected for classically complete geometrical coverage. Iterative image reconstruction techniques may be used to generate volumetric images based on measured volumetric data of at least a portion of the object. ## Claims ### Claim 1 An imaging device comprising: a transport system to transport an object; an X-ray source to emit a conical beam of X-ray radiation at a plurality of points along a trajectory of at least 180° about a direction of transport of the object to irradiate at least a portion of the object; a detector array to detect measurement data indicative of an interaction of the X-ray radiation with at least the portion of the object, the detector array disposed relative to the X-ray source to detect the measurement data along a scan path about the object; and a processing unit having a central processing unit programmable to: operate the imaging device in one of a first mode or a second mode: the first mode controlling a first speed of the transport system relative to the scan path to cause the detector array to detect measurement data that is sufficient for complete pi-line coverage; the second mode controlling a second speed of the transport system relative to the scan path to cause the detector array to detect measurement data that is insufficient for complete pi-line coverage, the second speed greater than the first speed; and compute reconstructed volumetric data representative of a volume of the object in the first mode or the second mode by applying at least one iteration of an iterative reconstruction to the measurement data to derive the reconstructed volumetric data. ### Claim 2 (depends on 1) The imaging device of claim 1 wherein the processing unit is further programmable to derive a volumetric image of the volume of the object based on the reconstructed volumetric data, the volumetric image comprising a three-dimensional model of the volume of the object or a two-dimensional projection of the volume of the object. ### Claim 3 (depends on 2) The imaging device of claim 2, further comprising a display to display the volumetric image. ### Claim 4 (depends on 1) The imaging device of claim 1, wherein the reconstructed volumetric data comprises mass density data or atomic number data or both. ### Claim 5 (depends on 1) The imaging device of claim 1, wherein the X-ray source comprises a conical beam X-ray source coupled to a rotating gantry. ### Claim 6 (depends on 5) The imaging device of claim 5, wherein the rotating gantry is configured to rotate the X-ray source through an angle of at least 180° about the direction of transport of the object. ### Claim 7 (depends on 1) The imaging device of claim 1, wherein the conical beam X-ray source comprises a scanning electron beam configured to irradiate sequentially a plurality of X-ray targets disposed at a plurality of points along a trajectory of at least 180° about the direction of transport of the object. ### Claim 8 (depends on 1) The imaging device of claim 1, wherein the conical beam X-ray source comprises a plurality of fixed electron beams configured to irradiate a plurality of X-ray targets disposed at a plurality of points along a trajectory of at least 180° about the direction of transport of the object. ### Claim 9 (depends on 1) The imaging device of claim 1, wherein the iterative reconstruction comprises at least one of a simultaneous algebraic reconstruction technique (SART), a simultaneous iterative reconstruction technique (SIRT), ordered subset convex technique (OSC), an adaptive statistical iterative reconstruction technique (ASIR), an OS-separable paraboloidal surrogates technique (OS-SPS), an algebraic reconstruction technique (ART), or a Kacsmarz reconstruction technique. ### Claim 10 (depends on 1) The imaging device of claim 1, wherein the processing unit is programmable to: initialize the iterative reconstruction using an output from a filtered back-projection reconstruction or other direct technique applied to the measurement data; and perform at least one iteration based on the initialized iterative reconstruction. ### Claim 11 (depends on 1) The imaging device of claim 1, wherein the pi-line through the object connects two different points along the scan path within one pitch in an axial direction, and wherein the measurement data is insufficient for complete pi-line coverage. ### Claim 12 An imaging system comprising: a transport system comprising a conveyor, to transport an object into the imaging system; an X-ray source configured to emit a conical beam of X-ray radiation at a plurality of points along a trajectory of at least 180° around the conveyor on a helical scan path relative to a direction of transport of the object, to irradiate at least a portion of the object, the helical scan path having a pitch greater than one; a detector array to detect measurement data indicative of an interaction of the X-ray radiation with the portion of the object, the detector array disposed relative to the X-ray source to detect the measurement data along the helical scan path; and a processing unit having a central processing unit programmable to: instruct the transport system to transport the object at a speed relative to the helical scan path to cause the detector array to detect measurement data that is insufficient for complete pi-line coverage due to a speed of traversal of the object relative to the helical scan path of the conical beam; and compute reconstructed volumetric data representative of a volume of the object by applying at least one iteration of an iterative reconstruction to the measurement data to derive the reconstructed volumetric data. ### Claim 13 (depends on 12) The imaging system of claim 12, wherein the processing unit is further programmable to derive a volumetric image of the volume of the object based on the reconstructed volumetric data, the volumetric image comprising a three-dimensional model of the volume of the object or a two-dimensional projection of the volume of the object. ### Claim 14 (depends on 13) The imaging system of claim 13, further comprising a display to display the volumetric image. ### Claim 15 (depends on 12) The imaging system of claim 12, wherein the reconstructed volumetric data comprises mass density data or atomic number data or both. ### Claim 16 (depends on 12) The imaging system of claim 12, wherein the X-ray source comprises a conical beam X-ray source coupled to a rotating gantry. ### Claim 17 (depends on 16) The imaging system of claim 16, wherein the rotating gantry is configured to rotate the X-ray source through an angle of at least 180° about the direction of transport of the object. ### Claim 18 (depends on 12) The imaging system of claim 12, wherein the conical beam X-ray source comprises a scanning electron beam configured to irradiate sequentially a plurality of X-ray targets disposed at a plurality of points along a trajectory of at least 180° about the direction of transport of the object. ### Claim 19 (depends on 12) The imaging system of claim 12, wherein the conical beam X-ray source comprises a plurality of fixed electron beams configured to irradiate a plurality of X-ray targets disposed at a plurality of points along a trajectory of at least 180° about the direction of transport of the object. ### Claim 20 (depends on 12) The imaging system of claim 12, wherein the iterative reconstruction comprises at least one of a simultaneous algebraic reconstruction technique (SART), a simultaneous iterative reconstruction technique (SIRT), ordered subset convex technique (OSC), an adaptive statistical iterative reconstruction technique (ASIR), an OS-separable paraboloidal surrogates technique (OS-SPS), an algebraic reconstruction technique (ART), or a Kacsmarz reconstruction technique. ### Claim 21 (depends on 12) The imaging system of claim 12, wherein the processing unit is programmable to: initialize the iterative reconstruction using an output from a filtered back-projection reconstruction or other direct technique applied to the measurement data; and perform at least one iteration based on the initialized iterative reconstruction. ### Claim 22 (depends on 12) The imaging system of claim 12, wherein the pi-line through the object connects two different points along the helical scan path within one pitch in an axial direction, and wherein the measurement data is insufficient for complete pi-line coverage. ### Claim 23 A method for reconstructing an image of a volume of an object from a cone-beam radiation pattern, comprising: receiving measurement data indicative of an interaction of X-ray radiation from a conical beam with at least a portion of an object disposed in a scan path thereof, the measurement data being insufficient for complete pi-line coverage due to maintaining a speed of traversal of the object relative to the scan path of the conical beam that prevents complete pi-line coverage; computing, using at least one processing unit having a central processing unit, reconstructed volumetric data representative of a volume of the object by applying at least one iteration of an iterative reconstruction methodology to the measurement data to derive the reconstructed volumetric data; and computing, using the at least one processing unit, a volumetric image of the volume of the object based on the reconstructed volumetric data. ### Claim 24 (depends on 23) The method of claim 23, wherein the volumetric image comprises a three-dimensional model of the volume of the object or a two-dimensional projection of the volume of the object. ### Claim 25 (depends on 23) The method of claim 23, further comprising displaying on a display the volumetric image or storing the volumetric image or the reconstructed volumetric data. ### Claim 26 (depends on 23) The method of claim 23, wherein a pi-line through the object connects two different points along the scan path within one pitch in an axial direction, and wherein the measurement data is insufficient for complete pi-line coverage. ### Claim 27 (depends on 23) The method of claim 23, wherein the conical beam emits from a conical X-ray source coupled to a rotating gantry. ### Claim 28 (depends on 23) The method of claim 23, wherein the conical X-ray source comprises a scanning electron beam configured to irradiate sequentially a plurality of X-ray targets disposed at a plurality of points along a trajectory of at least 180° about the direction of transport of the object. ### Claim 29 (depends on 23) The method of claim 23, wherein the conical beam X-ray source comprises a plurality of fixed electron beams configured to irradiate a plurality of X-ray targets disposed at a plurality of points along a trajectory of at least 180° about the direction of transport of the object. ### Claim 30 (depends on 23) The method of claim 23, wherein the iterative reconstruction methodology comprises at least one of a simultaneous algebraic reconstruction technique (SART), a simultaneous iterative reconstruction technique (SIRT), ordered subset convex technique (OSC), an adaptive statistical iterative reconstruction technique (ASIR), an OS-separable paraboloidal surrogates technique (OS-SPS), an algebraic reconstruction technique (ART), or a Kacsmarz reconstruction technique. ### Claim 31 (depends on 23) The method of claim 23, wherein the computing comprises: initializing the iterative reconstruction methodology using an output from a filtered back-projection reconstruction or other direct technique applied to the measurement data to provide an initialized iterative reconstruction; and performing at least one iteration based on the initialized iterative reconstruction. ### Claim 32 (depends on 23) The method of claim 23, wherein the reconstructed volumetric data comprises mass density data or atomic number data or both. ### Claim 33 An image reconstruction module for an imaging device, comprising: a communication interface; memory to store processor-executable instructions for an iterative reconstruction methodology for computing reconstructed volumetric data representative of a volume of an object; and a programmable processing unit having a central processing unit, communicatively coupled to the communication interface and the memory, wherein upon execution of the processor-executable instructions, the programmable processing unit operates to: receive measurement data indicative of an interaction of X-ray radiation from a cone-beam radiation pattern with at least a portion of an object disposed in a scan path thereof, the measurement data being insufficient for complete pi-line coverage due to maintaining a speed of traversal of the object relative to the scan path that prevents complete pi-line coverage; compute reconstructed volumetric data representative of a volume of the object by applying at least one iteration of an iterative reconstruction methodology to the measurement data to derive the reconstructed volumetric data; compute a volumetric image of the volume of the object based on the reconstructed volumetric data; and control the communication interface to transmit, or control the memory so as to store, the volumetric image or the reconstructed volumetric data. ### Claim 34 (depends on 33) The module of claim 33, wherein the volumetric image comprises a three-dimensional model of the volume of the object or a two-dimensional projection of the volume of the object. ### Claim 35 (depends on 34) The module of claim 34, further comprising a display to display the volumetric image. ### Claim 36 (depends on 33) The module of claim 33, wherein the reconstructed volumetric data comprises mass density data or atomic number data or both. ### Claim 37 (depends on 33) The module of claim 33, wherein the iterative reconstruction comprises at least one of a simultaneous algebraic reconstruction technique (SART), a simultaneous iterative reconstruction technique (SIRT), ordered subset convex technique (OSC), an adaptive statistical iterative reconstruction technique (ASIR), an OS-separable paraboloidal surrogates technique (OS-SPS), an algebraic reconstruction technique (ART), or a Kacsmarz reconstruction technique. ### Claim 38 (depends on 33) The module of claim 33, wherein the processing unit is programmable to: initialize the iterative reconstruction using an output from a filtered back-projection reconstruction or other direct technique applied to the measurement data; and perform at least one iteration based on the initialized iterative reconstruction. ### Claim 39 (depends on 33) The module of claim 33, wherein the pi-line through the object connects two different points along the scan path within one pitch in an axial direction, and wherein the measurement data is insufficient for complete pi-line coverage. ### Claim 40 A non-transitory machine readable medium storing instructions executable by a processing device having a central processing unit, wherein execution of the instructions causes the processing device to carry out a method for reconstructing a volume of an object from a cone-beam radiation pattern, the method comprising: receiving measurement data indicative of an interaction of X-ray radiation from a cone-beam radiation pattern with at least a portion of an object disposed in a scan path thereof, the measurement data being insufficient for complete pi-line coverage due to maintaining a speed of traversal of the object relative to the scan path that prevents complete pi-line coverage; computing reconstructed volumetric data representative of a volume of the object by applying at least one iteration of an iterative reconstruction methodology to the measurement data to derive the reconstructed volumetric data; and computing a volumetric image of the volume of the object based on the reconstructed volumetric data. ### Claim 41 (depends on 40) The machine readable medium of claim 40, wherein the volumetric image comprises a three-dimensional model of the volume of the object or a two-dimensional projection of the volume of the object. ### Claim 42 (depends on 41) The machine readable medium of claim 41, wherein the method further comprises displaying the volumetric image on a display. ### Claim 43 (depends on 40) The machine readable medium of claim 40, wherein the reconstructed volumetric data comprises mass density data or atomic number data or both. ### Claim 44 (depends on 40) The machine readable medium of claim 40, wherein the iterative reconstruction comprises at least one of a simultaneous algebraic reconstruction technique (SART), a simultaneous iterative reconstruction technique (SIRT), ordered subset convex technique (OSC), an adaptive statistical iterative reconstruction technique (ASIR), an OS-separable paraboloidal surrogates technique (OS-SPS), an algebraic reconstruction technique (ART), or a Kacsmarz reconstruction technique. ### Claim 45 (depends on 40) The machine readable medium of claim 40, wherein the processing unit is programmable to: initialize the iterative reconstruction using an output from a filtered back-projection reconstruction or other direct technique applied to the measurement data; and perform at least one iteration based on the initialized iterative reconstruction. ### Claim 46 (depends on 40) The machine readable medium of claim 40, wherein the pi-line through the object connects two different points along the scan path within one pitch in an axial direction, and wherein the measurement data is insufficient for complete pi-line coverage.