Method for determining the location and orientation of a fiducial reference
Inventors
Daon, Ehud (Udi) • Beckett, Martin Gregory • Medina Rodriguez, Alvaro Andres
Assignees
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Publication Number
US-9918657-B2
Publication Date
2018-03-20
Expiration Date
Abstract
A method for determining the 3D location and orientation of a fiducial reference comprises disposing the fiducial reference so as to render a part of the fiducial reference observable by a tracker; obtaining from the tracker scan data of the part of the fiducial reference that is observable by the tracker; obtaining predetermined geometric information about location points on the fiducial reference, the geometric information containing three-dimensional coordinates of the location points relative to the structure of the fiducial reference; identifying within the scan data at least three location points having coordinates in the predetermined geometric information; and determining from the scan data and the coordinates of the three identified location points in the predetermined geometric information the 3D location and orientation of the fiducial reference.
Core Innovation
The invention determines the three-dimensional location and orientation of a fiducial reference from scan data using tracker image data and predetermined geometric information. A fiducial reference is disposed to render a part of the fiducial reference observable by a non-stereo tracker, and image data of the observable part is obtained from the tracker. Predetermined geometric information about location points on the fiducial reference comprises three-dimensional coordinates of the location points relative to the structure of the fiducial reference.
Within the image data, at least three location points are identified such that their coordinates are arranged along at least two non-parallel lines in the predetermined geometric information. The three-dimensional location and orientation of the fiducial reference are then determined from the scan data and from the coordinates of the at least three identified location points in the predetermined geometric information. This provides a pose computation that ties identifiable location points observed by the non-stereo tracker to their predetermined three-dimensional coordinates.
The disclosure further supports predetermined geometric information that can be obtained from a database and can be stored, including point sets arranged along at least two non-parallel lines, such as four points on two non-parallel lines and distributed points in three dimensions. The fiducial reference can be determined when only a partially observable portion remains visible to the tracker, so that the required location points stay observable, enabling continued determination of location and orientation.
Claims Coverage
The document includes two independent claims: a method claim and a system claim. Both cover the same core inventive concept and rely on identifying location points arranged along at least two non-parallel lines using predetermined 3D coordinates and determining three-dimensional location and orientation from scan data.
Non-stereo tracker observation with observable fiducial part
Disposing the fiducial reference to render a part of the fiducial reference observable by a non-stereo tracker, and obtaining from the tracker image data of the part of the fiducial reference that is observable by the tracker.
Predetermined 3D coordinates of fiducial location points
Obtaining predetermined geometric information about location points on the fiducial reference, the geometric information comprising three-dimensional coordinates of the location points relative to the structure of the fiducial reference.
Location point identification along at least two non-parallel lines
Identifying within the image data at least three location points having coordinates arranged along at least two non-parallel lines in the predetermined geometric information.
Pose determination from scan data and identified point coordinates
Determining the three-dimensional location and orientation of the fiducial reference from the scan data and from the coordinates of the at least three identified location points in the predetermined geometric information.
System with computing device and non-stereo tracker
A computing device including a processor and associated memory, and a non-stereo tracker coupled to the computing device and configured to observe image data from a surgical site and send the image data from a surgical site to the computing device.
Instructions to obtain geometric information and compute pose
Memory stores computing device instructions to obtain image data from the tracker that includes at least a part of the fiducial reference that is observable by the tracker, obtain predetermined geometric information comprising three-dimensional coordinates, identify at least three location points arranged along at least two non-parallel lines, and determine the three-dimensional location and orientation from the scan data and the coordinates of the at least three identified location points.
Across the independent method and system claims, the inventive scope is focused on combining non-stereo tracker-observed image data with predetermined three-dimensional coordinates of fiducial location points whose coordinates align along at least two non-parallel lines, and then determining the fiducial reference’s three-dimensional location and orientation from the scan data and the identified point coordinates.
Stated Advantages
Enables determining the three-dimensional location and orientation of a fiducial reference from scan data using tracker image data and predetermined geometric information.
Supports determination when only a partially observable portion of the fiducial reference remains visible to the non-stereo tracker, while required location points remain observable.
Enables robust identification of location points by requiring coordinates arranged along at least two non-parallel lines in the predetermined geometric information.
Documented Applications
Surgical fiducial registration in a surgical site using a non-stereo tracker and scan data to determine fiducial pose for real-time monitoring and instrument guidance.
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