# US 2014/0153694 A1 · Method for determining geometric imaging properties of a flat panel detector, correspondingly adapted x-ray inspection system and calibration phantom > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153694 A1 - Document ID: US20140153694A1 - Status: Published application - Kind: A1 - Application number: 14/082,641 - Filed: 2013-11-18 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: GE Sensing & Inspection Technologies GmbH - Applicants: GE Sensing & Inspection Technologies GmbH - Inventors: Alexander SUPPES; Pavel POKUTNEV; Eberhard NEUSER; Nils ROTHE - Web page: https://patentgrep.com/patent/US20140153694A1 ## CPC - G01T 7/005: {calibration techniques (stabilization of spectrometer G01T1/40)} - A61B 6/5258: {involving detection or reduction of artifacts or noise} - A61B 6/583: {using calibration phantoms} - A61B 6/585: {Calibration of detector units} - G01N 23/046: using tomography, e.g. computed tomography [CT] - A61B 6/03: Computed tomography [CT] - A61B 6/4233: {using matrix detectors} - F04C 2270/041: Controlled or regulated - G01N 2223/303: calibrating, standardising - G01N 2223/3035: phantom - G01N 2223/419: computed tomograph - G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - 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) - F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS ## Abstract A method for determining geometric imaging properties of a flat panel detector in an x-ray inspection system includes the steps arranging a calibration phantom between an x-ray source and the flat panel detector, wherein the calibration phantom comprises at least one discrete geometric object; recording at least one x-ray image of the calibration phantom with the flat panel detector, wherein at least one discrete geometric shape is generated in the x-ray image by imaging the at least one discrete geometric object of the calibration phantom; and determining a location-dependent distortion error of the flat panel detector from the at least one x-ray image on the basis of at least one characteristic of the at least one discrete geometric shape. All characteristics of the at least one discrete geometric shape used for determining the location-dependent distortion error are independent of the dimensions of the calibration phantom. ## Claims ### Claim 1 A method for determining geometric imaging properties of a flat panel detector in an x-ray inspection system, the method comprising: arranging a calibration phantom between an x-ray source and the flat panel detector, wherein the calibration phantom comprises at least one discrete geometric object; recording at least one x-ray image of the calibration phantom with the flat panel detector, wherein at least one discrete geometric shape is generated in the x-ray image by imaging the at least one discrete geometric object of the calibration phantom; and determining a location-dependent distortion error of the flat panel detector from the at least one x-ray image on the basis of at least one characteristic of the at least one discrete geometric shape; wherein all of the at least one characteristic of the at least one discrete geometric shape used for determining the location-dependent distortion error are independent of the dimensions of the calibration phantom. ### Claim 2 (depends on 1) The method according to claim 1, wherein a plurality of discrete geometric shapes is recorded at different positions of the detector surface by imaging the at least one discrete geometric object of the calibration phantom. ### Claim 3 (depends on 2) The method according to claim 2, wherein the at least one discrete geometric object are uniform, and a characteristic of the at least one characteristic is the deviation of the geometric shapes from uniformity. ### Claim 4 (depends on 2) The method according to claim 2, wherein the at least one discrete geometric object are of equal size, and a characteristic of the at least one characteristic is a deviating size among the geometric shapes. ### Claim 5 (depends on 2) The method according to claim 2, wherein the at least one discrete geometric object have an equal shape, and a characteristic of the at least one characteristic is the deviating shape among the geometric shapes. ### Claim 6 (depends on 2) The method according to claim 2, wherein the at least on discrete geometric object are arranged at regular intervals and/or periodically, and a characteristic of the at least one characteristic is the arrangement of the geometric shapes deviating from regularity and/or periodicity. ### Claim 7 (depends on 2) The method according to claim 2, wherein the at least on discrete geometric object are arranged to contact each other. ### Claim 8 (depends on 1) The method according to claim 1, wherein the at least one discrete geometric object is at least one straight line or is arranged in at least one straight line, and a characteristic of the at least one characteristic is the deviation of the geometric shape from straightness. ### Claim 9 (depends on 1) The method according to claim 1, wherein the at least one discrete geometric object is at least one cylindrical object having a constant diameter, and a characteristic of the at least one characteristic is a deviation of the geometric shape from the constant diameter. ### Claim 10 (depends on 1) The method according to claim 1, wherein the at least one characteristic of the at least one geometric shape and/or the location-dependent distortion error is determined from a three-dimensional reconstructed x-ray image. ### Claim 11 An X-ray inspection system comprising an x-ray source, a flat panel detector, a calibration phantom comprising at least one discrete geometric object, and an electronic data processing device, wherein the x-ray inspection system is adapted to record at least one x-ray image of the calibration phantom placed between the x-ray source and the flat panel detector, at least one discrete geometric shape is generated in the x-ray image by imaging the at least one discrete geometric object of the calibration phantom, the data processing device is adapted to determine a location-dependent distortion error of the flat panel detector from the at least one x-ray image on the basis of at least one characteristic of the discrete geometric shape, all of the at least one characteristics of the at least one discrete geometric shape used for determining the location-dependent distortion error are independent of the dimensions of the calibration phantom or of exactly knowing the dimensions of the calibration phantom. ### Claim 12 A calibration phantom for determining geometric imaging properties of a flat panel detector in an x-ray inspection system, comprising a cylindrical tube and a row of uniform geometric objects arranged in the cylindrical tube. ### Claim 13 (depends on 12) The calibration phantom according to claim 12, wherein the row of uniform geometric objects are spheres having an equal diameter. ### Claim 14 (depends on 12) The calibration phantom according to claim 12, wherein the row of uniform geometric objects are not connected with each other and/or are arranged to contact each other. ### Claim 15 (depends on 12) The calibration phantom according to claim 12, wherein a plurality of geometric objects, are arranged in a plane perpendicular to the tube axis. ### Claim 16 (depends on 12) The calibration phantom according to claim 12, wherein a plurality of geometric objects are arranged in a plane perpendicular to the tube axis, wherein the plurality of geometric objects comprise at least three geometric objects.