Fiducial detection system
First Claim
1. A fiducial mark for detection by a camera comprising:
- a circular outer perimeter; and
patterns on an inside of the outer perimeter for reading an identity code including higher information density per area than a pattern of concentric rings.
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Accused Products
Abstract
A new fiducial design allows having thousands of different codes. These fiducials are printed on a standard black-and-white (or color) printer and easily could be mounted on a walls, ceiling and objects in a room. The design includes “solid” outside mono-color ring and 2-D dense inside coding scheme. Image processing algorithms are implemented in Smart Camera with a built-in DSP to run all required image-processing tasks. A tracking system implementation includes an inertial measurement unit and one outward-looking wide-angle Smart Camera with possible extensions to number of stationary inward-looking cameras. The system operates in various real-world lighting conditions without any user intervention due to homomorphic image processing processes for extracting fiducials in the presence of very non-uniform lighting.
272 Citations
41 Claims
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1. A fiducial mark for detection by a camera comprising:
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a circular outer perimeter; and
patterns on an inside of the outer perimeter for reading an identity code including higher information density per area than a pattern of concentric rings. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for finding a centroid of an outer rim of a fiducial comprising:
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capturing an image of the fiducial;
filling an interior of the fiducial image to match a color of the outer rim resulting in one solid ellipse-like shape; and
calculating the centroid of the one solid ellipse-like shape. - View Dependent Claims (11)
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12. A method comprising:
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determining a centroid of a framing object and all interior objects of a fiducial image; and
calculating a centroid of a virtual filled object using a formula for the centroid of a combination object.
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13. A method of detecting fiducial marks comprising:
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capturing an image of a fiducial mark, the fiducial mark comprising a circular outer perimeter, patterns on an inside of the outer perimeter for reading an identity code including higher information density per area than a pattern of concentric rings, a two dimensional (2D) array of encoding areas, each of the encoding areas having a color selected from a set of N colors, and having approximately equal sizes and features for establishing a reference frame for reading the patterns;
determining an origin of the image from a first feature; and
determining an x-axis and a y-axis position of the image from second features. - View Dependent Claims (14)
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15. A hybrid tracking system comprising:
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a camera for capturing an image;
an inertial measurement unit; and
a sensor fusion core including a means for detecting a fiducial within the image. - View Dependent Claims (16, 17, 18)
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19. A two-dimensional (2D) fiducial for image processing comprising:
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an outer ring of 1 u width;
two data rings, each data ring having a 1 u width; and
an inner ring with 1 u width, wherein u is one length unit. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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26. An image processing target comprising:
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a black colored outer ring of 1 u width;
two data rings, each data ring having a 1 u width and including eight sectors with 45°
for each sector; and
an inner ring of 1 u width comprising a black circle with a white eye in a center. - View Dependent Claims (27)
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28. A method of fiducial acquisition in motion tracking systems comprising:
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finding candidate objects;
downsampling an original image to 320×
240 for speed;
enhancing a contrast of the image;
detecting an edge of the image;
filtering blurs for increasing a number of disconnected objects in the image;
binarizing with a local threshold value; and
selecting a final candidate. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35)
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36. An image processing system for a wearable vision-inertial self tracker comprising:
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an inertial measurement unit (IMU);
a sensor fusion core (SFC) including means for acquiring, tracking and tracquisitioning a two-dimensional (2D) bar-code fiducial; and
a smart camera device. - View Dependent Claims (37, 38)
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39. A two dimensional (2D) fiducial design for image processing comprising:
a sequence of concentric rings, each of the rings including a plurality of mono-colored information sectors, each sector being of approximately a same size such that inner rings have less sectors than outer rings. - View Dependent Claims (40, 41)
Specification