Patent ID: 11879854
Assignee: BAKER HUGHES OILFIELD OPERATIONS LLC
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 9:
10. 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.