Back to results
US 11,879,854 B2Granted
Positioning of x-ray imaging system using an optical camera
AssigneeBaker Hughes Oilfield Operations LLC
InventorsJing Xu, Li Li, Lisa Ma
Life of this patent
Estimating the term…
Abstract
In an embodiment, a method of navigational calibration for an x-ray inspection system including an optical camera is provided. The method employs a novel two-dimensional calibration phantom. The calibration phantom can be employed to validate a navigational calibration between positions within camera images and an x-ray beam axis. The calibration phantom can be further employed to identify and compensate for incorrect navigational calibration.
Claims18
A method of navigational calibration for an x-ray inspection system, comprising:
- mounting a calibration phantom on a moveable stage, wherein a first surface of the calibration phantom is generally planar and includes an optically visible pattern illustrated thereon, the pattern including:
- a plurality of polygons of different sizes, wherein a first polygon of the plurality of polygons is inset and centered within a second polygon of the plurality of polygons;
- a center mark at a center of the calibration phantom;
- and
- a vertex mark at a vertex of one of the plurality of polygons;
- wherein a physical location of the vertex mark is offset from a physical location of the center mark by a predetermined first offset distance in a first direction and a predetermined second offset distance in a second direction, and wherein the first and second directions lie in the plane of the first surface and are orthogonal to one another;
- generating a graphical user interface (GUI) including a sequence of images of a field of view of an optical video camera and a crosshair overlaid upon the sequence of images;
- outputting the GUI for display;
- moving the moveable stage to a first location, wherein the calibration phantom is within the field of view of the video camera such that the crosshair center is aligned with the center mark within the GUI;
- determining a calibration ratio defined as a physical distance per pixel within the sequence of images when the moveable stage is at the first location;
- receiving the physical location of the vertex mark;
- moving the moveable stage from the first position to a second position by moving the first offset distance in the first direction and moving the second offset distance in the second direction;
- measuring, at the second location, respective first pixel differences in the first and second directions between a pixel location of the predetermined vertex mark within the GUI and a pixel location of the crosshair center within the GUI;
- and
- outputting a calibration status based upon a comparison between the first pixel differences in the first and second directions and a threshold value.
12 more elements
A computer program product comprising a non-transitory machine-readable medium storing instructions that, when executed by at least one programmable processor, cause the at least one programmable processor to perform operations comprising:
- generating a graphical user interface (GUI) including a sequence of images of a field of view of an optical video camera and a crosshair overlaid upon the sequence of images;
- outputting the GUI for display;
- moving the moveable stage to a first location, wherein a calibration phantom is within the field of view of the video camera, wherein a first surface of the calibration phantom is generally planar and includes an optically visible pattern illustrated thereon, the pattern including:
- a plurality of polygons of different sizes, wherein a first polygon of the plurality of polygons is inset and centered within a second polygon of the plurality of polygons;
- a center mark at a center of the calibration phantom;
- and
- a vertex mark at a vertex of one of the plurality of polygons;
- wherein a physical location of the vertex mark is offset from a physical location of the center mark by a predetermined first offset distance in a first direction and a predetermined second offset distance in a second direction, and wherein the first and second directions lie in the plane of the first surface and are orthogonal to one another;
- wherein the crosshair center is aligned with the center mark within the GUI at the first position;
- determining a calibration ratio defined as a physical distance per pixel within the sequence of images when the moveable stage is at the first location;
- receiving the physical location of the vertex mark;
- moving the moveable stage from the first position to a second position by moving the first offset distance in the first direction and moving the second offset distance in the second direction;
- measuring, at the second location, respective first pixel differences in the first and second directions between a pixel location of the predetermined vertex mark within the GUI and a pixel location of the crosshair center within the GUI;
- and
- outputting a calibration status based upon a comparison between the first pixel differences in the first and second directions and a threshold value.
12 more elements
Dependencies are inferred from the claim text.