Patents by Inventor Xiaohui Zhan
Xiaohui Zhan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20220233162Abstract: A method and a system for providing calibration for a polychromatic photon counting detector forward counting model. Measurements with multiple materials and known path lengths are used to calibrate the photon counting detector counting response of the forward model. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at plural tube voltage settings for each detector pixel. The beam hardening corrections are then applied to the measured projection data sinogram, and the corrected sinogram is reconstructed to the counting image at the selected single energy.Type: ApplicationFiled: January 22, 2021Publication date: July 28, 2022Applicant: CANON MEDICAL SYSTEMS CORPORATIONInventors: Xiaohui ZHAN, Xiaofeng NIU, Ilmar HEIN
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Publication number: 20220229196Abstract: A method and a system for a two-step calibration method for the polychromatic semiconductor-based PCD forward counting model, to account for various pixel summing readout modes for imaging at different resolutions. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at plural tube voltage settings for each detector pixel. To correct the variation of the detector response due to different PCD sub-pixel summing schemes, the embodiments calibrate forward model parameters based on the various pixel readout modes.Type: ApplicationFiled: January 20, 2021Publication date: July 21, 2022Applicant: CANON MEDICAL SYSTEMS CORPORATIONInventors: Xiaohui ZHAN, Xiaofeng NIU
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Publication number: 20220128488Abstract: A method and a system for providing calibration for a photon counting detector forward model for material decomposition. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at each tube voltage setting for each detector pixel.Type: ApplicationFiled: January 7, 2022Publication date: April 28, 2022Applicant: CANON MEDICAL SYSTEMS CORPORATIONInventors: Xiaohui ZHAN, Xiaofeng NIU
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Patent number: 11316712Abstract: A CANopen-based data transmission gateway changeover method includes: making an active gateway go alive, and mutually monitoring heartbeat packet status together with a standby gateway over an active-standby gateway communications network; keeping the active gateway alive and recording a breakdown of the standby gateway if no heartbeat packet of the standby gateway is detected within a preset heartbeat period and a heartbeat packet of the active gateway is successfully transmitted on the active-standby gateway communications network; requesting the standby gateway to go alive if the heartbeat packet of the active gateway fails to be transmitted on the active-standby gateway communications network; stopping requesting the standby gateway in a first in-vehicle communications network to go alive, and requesting the standby gateway to go alive; and keeping the active gateway alive and recording a breakdown of the standby gateway if still no response is received from the standby gateway.Type: GrantFiled: June 20, 2018Date of Patent: April 26, 2022Assignee: BYD COMPANY LIMITEDInventors: Xiaohui Zhan, Wenxiao Zeng, Long Zhao
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Patent number: 11249035Abstract: A method and a system for providing calibration for a photon counting detector forward model for material decomposition. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at each tube voltage setting for each detector pixel.Type: GrantFiled: June 29, 2020Date of Patent: February 15, 2022Assignee: CANON MEDICAL SYSTEMS CORPORATIONInventors: Xiaohui Zhan, Xiaofeng Niu
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Patent number: 11229413Abstract: An embodiment of a computed tomography apparatus includes an x-ray source and scan control circuitry configured to control the x-ray source to expose a subject with x-rays over a scan having a plurality of views. A detector is disposed to receive x-rays from the x-ray source, has a plurality of anodes arranged in groups, and a common conductive strip between the anodes. Photon counting circuits are respectively provided for each of the anodes and have adjustable operating parameters. Connection circuitry is configured to adaptively connect, in a first mode, each anode to one of the photon counting circuits and, in a second mode, each anode in a group to a same one of the photon counting circuits. Processing circuitry, connected to the connection circuitry and the photon counting circuits, is configured to, for each of the views, select the first mode or the second mode and adjust the operating parameters based upon exposure data obtained from exposing the subject with the x-rays from the x-ray source.Type: GrantFiled: July 2, 2020Date of Patent: January 25, 2022Assignee: CANON MEDICAL SYSTEMS CORPORATIONInventors: Xiaochun Lai, Liang Cai, Yi Qiang, Xiaohui Zhan
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Publication number: 20220000437Abstract: An embodiment of a computed tomography apparatus includes an x-ray source and scan control circuity configured to control the x-ray source to expose a subject with x-rays over a scan having a plurality of views. A detector is disposed to receive x-rays from the x-ray source, has a plurality of anodes arranged in groups, and a common conductive strip between the anodes. Photon counting circuits are respectively provided for each of the anodes and have adjustable operating parameters. Connection circuitry is configured to adaptively connect, in a first mode, each anode to one of the photon counting circuits and, in a second mode, each anode in a group to a same one of the photon counting circuits. Processing circuitry, connected to the connection circuitry and the photon counting circuits, is configured to, for each of the views, select the first mode or the second mode and adjust the operating parameters based upon exposure data obtained from exposing the subject with the x-rays from the x-ray source.Type: ApplicationFiled: July 2, 2020Publication date: January 6, 2022Applicant: Canon Medical Systems CorporationInventors: Xiaochun LAI, Liang CAI, Yi QIANG, Xiaohui ZHAN
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Publication number: 20210404975Abstract: A method and a system for providing calibration for a photon counting detector forward model for material decomposition. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at each tube voltage setting for each detector pixel.Type: ApplicationFiled: June 29, 2020Publication date: December 30, 2021Applicant: CANON MEDICAL SYSTEMS CORPORATIONInventors: Xiaohui Zhan, Xiaofeng Niu
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Publication number: 20210367808Abstract: The present disclosure discloses a CANopen-based data transmission gateway changeover method, system and apparatus.Type: ApplicationFiled: June 20, 2018Publication date: November 25, 2021Inventors: Xiaohui ZHAN, Wenxiao ZENG, Long ZHAO
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Patent number: 11147522Abstract: According to one embodiment, a photon-counting detector (PCD) includes a plurality of macro-pixels. The plurality of macro-pixels arranged on a semiconductor crystal has a first face and a second face. The first face and the second face are parallel. Each macro-pixel from the plurality of macro-pixels is configured to acquire projection data for generating a reconstructed image. The plurality of macro-pixels each includes at least one large micro-pixel is disposed within the each macro-pixel and at least two small micro-pixels is disposed within the each macro-pixel. Each of the at least two small micro-pixels has a surface area that is less than a surface area of the at least one large micro-pixel.Type: GrantFiled: May 28, 2019Date of Patent: October 19, 2021Assignee: Canon Medical Systems CorporationInventors: Liang Cai, Xiaohui Zhan, Kevin Christopher Zimmerman, Richard Thompson
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Patent number: 11013487Abstract: An apparatus and method are described using a forward model to correct pulse pileup in spectrally resolved X-ray projection data from photon-counting detectors (PCDs). The forward model represents pulse pileup effects using an integral in which the integrand includes a term that is a function of a count rate, which term is called a spectrum distortion correction function. This correction function can be represented as superposition of basis energy functions and corresponding polynomials of the count rate, which are defined by the polynomial coefficients. To calibrate the forward model, the polynomial coefficients are adjusted to optimize an objective function, which uses calibration data having known projections lengths for the material components of a material decomposition. To determine projection lengths for projection data from a computed tomography scan, the calibrated polynomial coefficients are held constant and the projection lengths are adjusted to optimize an objective function.Type: GrantFiled: October 18, 2019Date of Patent: May 25, 2021Assignee: CANON MEDICAL SYSTEMS CORPORATIONInventors: Jian Zhou, Xiaohui Zhan, Zhou Yu
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Publication number: 20210113178Abstract: An apparatus and method are described using a forward model to correct pulse pileup in spectrally resolved X-ray projection data from photon-counting detectors (PCDs). The forward model represents pulse pileup effects using an integral in which the integrand includes a term that is a function of a count rate, which term is called a spectrum distortion correction function. This correction function can be represented as superposition of basis energy functions and corresponding polynomials of the count rate, which are defined by the polynomial coefficients. To calibrate the forward model, the polynomial coefficients are adjusted to optimize an objective function, which uses calibration data having known projections lengths for the material components of a material decomposition. To determine projection lengths for projection data from a computed tomography scan, the calibrated polynomial coefficients are held constant and the projection lengths are adjusted to optimize an objective function.Type: ApplicationFiled: October 18, 2019Publication date: April 22, 2021Applicant: CANON MEDICAL SYSTEMS CORPORATIONInventors: Jian ZHOU, Xiaohui ZHAN, Zhou YU
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Patent number: 10952698Abstract: A method and apparatuses are provided to estimate, for two or more detector elements in an array of photon-counting detector elements, respective energy spectra of an X-ray beam incident on the corresponding detector elements from an X-ray source, the energy spectra being estimated by modeling X-ray attenuation as a function of X-ray energy when an X-ray beam is transmitted through a filter and set, for each detector element of the two or more detector elements, a first energy threshold of an energy range that is detected by the each detector element, the first energy threshold of the each detector element being based on the estimated energy spectra of the each detector element.Type: GrantFiled: April 18, 2019Date of Patent: March 23, 2021Assignee: CANON MEDICAL SYSTEMS CORPORATIONInventors: Xiaohui Zhan, Kevin Christopher Zimmerman, Cai Liang
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Publication number: 20200330065Abstract: A method and apparatuses are provided to estimate, for two or more detector elements in an array of photon-counting detector elements, respective energy spectra of an X-ray beam incident on the corresponding detector elements from an X-ray source, the energy spectra being estimated by modeling X-ray attenuation as a function of X-ray energy when an X-ray beam is transmitted through a filter and set, for each detector element of the two or more detector elements, a first energy threshold of an energy range that is detected by the each detector element, the first energy threshold of the each detector element being based on the estimated energy spectra of the each detector element.Type: ApplicationFiled: April 18, 2019Publication date: October 22, 2020Inventors: Xiaohui ZHAN, Kevin Christopher Zimmerman, Cai Liang
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Method and apparatus for partial volume identification from photon-counting macro-pixel measurements
Patent number: 10799192Abstract: A method and apparatuses are provided to identify and correct partial volume errors (PVEs) in material decomposition of a spectral computed tomography (CT) scan, due to different X-ray trajectories incident on a same macro-pixel passing through different material components (e.g., bone and water). Macro-pixels are virtual crystals generated by aggregating the signals/counts from several smaller actual pixels (i.e., micro-pixels) of a detector array. Thus, when a PVE is identified within a macro-pixel, the separate signals/counts from the micro-pixels can be used for material decomposition, instead of the aggregated signals/counts of the macro-pixel, thereby providing improved spatial resolution of the material components and, at least partial, overcoming the PVE. A measure of the difference between spectrally-resolved counts based a material projection lengths (e.g., from a calibrated lookup table) and the measured counts of the macro-pixel can be used to identify PVEs, e.g.Type: GrantFiled: November 6, 2018Date of Patent: October 13, 2020Assignee: Canon Medical Systems CorporationInventors: Kevin Christopher Zimmerman, Liang Cai, Hiroaki Miyazaki, Xiaohui Zhan -
METHOD AND APPARATUS FOR PARTIAL VOLUME IDENTIFICATION FROM PHOTON-COUNTING MACRO-PIXEL MEASUREMENTS
Publication number: 20200138386Abstract: A method and apparatuses are provided to identify and correct partial volume errors (PVEs) in material decomposition of a spectral computed tomography (CT) scan, due to different X-ray trajectories incident on a same macro-pixel passing through different material components (e.g., bone and water). Macro-pixels are virtual crystals generated by aggregating the signals/counts from several smaller actual pixels (i.e., micro-pixels) of a detector array. Thus, when a PVE is identified within a macro-pixel, the separate signals/counts from the micro-pixels can be used for material decomposition, instead of the aggregated signals/counts of the macro-pixel, thereby providing improved spatial resolution of the material components and, at least partial, overcoming the PVE. A measure of the difference between spectrally-resolved counts based a material projection lengths (e.g., from a calibrated lookup table) and the measured counts of the macro-pixel can be used to identify PVEs, e.g.Type: ApplicationFiled: November 6, 2018Publication date: May 7, 2020Applicant: Canon Medical Systems CorporationInventors: Kevin Christopher ZIMMERMAN, Liang CAI, Hiroaki MIYAZAKI, Xiaohui ZHAN -
Patent number: 10593070Abstract: A method and apparatus is provided to simulate and correct for scatter flux detected in a computed tomography (CT) scanner. The scatter flux from a bowtie filter and an anti-scatter grid are pre-calculated to generate respective scatter tables. Scatter from an imaged object is simulated for some views of a CT scan using a three-step radiative transfer equation (RTE) method. Using the simulated scatter flux from these views, an accelerated simulation method, such as a multiplicative method, an additive method, and a kernel-based method, can determine scatter flux for the remaining views. The spatial model for X-ray scatter from the object can be based on a reconstructed image of object, and can be segmented into organs and material components having different scatter cross-sections. A scatter model outside the imaging region can be extrapolated using low-dose scanning, a scout scan, and/or anatomical information.Type: GrantFiled: December 22, 2017Date of Patent: March 17, 2020Assignee: Canon Medical Systems CorporationInventors: Yujie Lu, Xiaohui Zhan, Zhou Yu, Richard Thompson
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Publication number: 20200069266Abstract: According to one embodiment, a photon-counting detector (PCD) includes a plurality of macro-pixels. The plurality of macro-pixels arranged on a semiconductor crystal has a first face and a second face. The first face and the second face are parallel. Each macro-pixel from the plurality of macro-pixels is configured to acquire projection data for generating a reconstructed image. The plurality of macro-pixels each includes at least one large micro-pixel is disposed within the each macro-pixel and at least two small micro-pixels is disposed within the each macro-pixel. Each of the at least two small micro-pixels has a surface area that is less than a surface area of the at least one large micro-pixel.Type: ApplicationFiled: May 28, 2019Publication date: March 5, 2020Applicant: Canon Medical Systems CorporationInventors: Liang CAI, Xiaohui ZHAN, Kevin Christopher ZIMMERMAN, Richard THOMPSON
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Publication number: 20190197740Abstract: A method and apparatus is provided to simulate and correct for scatter flux detected in a computed tomography (CT) scanner. The scatter flux from a bowtie filter and an anti-scatter grid are pre-calculated to generate respective scatter tables. Scatter from an imaged object is simulated for some views of a CT scan using a three-step radiative transfer equation (RTE) method. Using the simulated scatter flux from these views, an accelerated simulation method, such as a multiplicative method, an additive method, and a kernel-based method, can determine scatter flux for the remaining views. The spatial model for X-ray scatter from the object can be based on a reconstructed image of object, and can be segmented into organs and material components having different scatter cross-sections. A scatter model outside the imaging region can be extrapolated using low-dose scanning, a scout scan, and/or anatomical information.Type: ApplicationFiled: December 22, 2017Publication date: June 27, 2019Applicant: Toshiba Medical Systems CorporationInventors: Yujie Lu, Xiaohui Zhan, Zhou Yu, Richard Thompson