METHOD AND SYSTEM FOR CHARACTERIZING AND VISUALIZING ELECTROMAGNETIC TRACKING ERRORS
First Claim
1. An electromagnetic tracking system (200), comprising:
- an electromagnetic sensor array (30) including at least two electromagnetic sensors arranged in a known geometrical configuration; and
a data processor (220) in electrical communication with the electromagnetic sensor array (30) to receive signals indicative of a sensing of an electromagnetic field by the electromagnetic sensors,wherein the data processor (220) is operable to compute intra-operative relative errors (43) responsive to a movement of the electromagnetic sensor array (30) to numerous estimation positions within an intra-operative electromagnetic field,wherein each intra-operative relative error (43) is an absolute differential between a calibrated distance (40) of an electromagnetic sensor pair and a sensed distance between the electromagnetic sensor pair within the intra-operative electromagnetic field,wherein the data processor (220) is further operable to estimate intra-operative absolute errors (44) responsive to a plotting of the intra-operative relative errors (43) within a pre-operative error map (42) representative of a statistical relationship between pre-operative absolute errors (41) and pre-operative relative errors (41) derived from a movement of the electromagnetic sensor array (30) to numerous measurement positions within a pre-operative electromagnetic field,wherein each intra-operative absolute error (44) is an absolute differential between an estimation position and a sensed position of an electromagnetic sensor within the intra-operative electromagnetic field,wherein each pre-operative absolute error (41) is an absolute differential between a measurement position and a sensed position of an electromagnetic sensor within the pre-operative electromagnetic field, andwherein each pre-operative relative error (41) is an absolute differential between a calibrated distance (40) and a sensed distance between an electromagnetic sensor pair within the pre-operative electromagnetic field.
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Accused Products
Abstract
A calibration/surgical tool (90, 160) includes an electromagnetic sensor array (30) of two or more electromagnetic sensors in a known geometrical configuration. Electromagnetic tracking errors are characterized by a mapping of pre-operative absolute and relative errors based on a movement of a calibrated calibration/surgical tool (90, 160) through a pre-operative electromagnetic field. Using statistical mapping, a desired absolute error field (46) is measured either in the clinic as the part of daily quality control checks, or before the patient comes in or in vivo. A resulting error field (46) may be displayed to the physician to provide clear visual feedback about measurement confidence or reliability of localization estimates of the absolute errors in electromagnetic tracking.
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Citations
20 Claims
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1. An electromagnetic tracking system (200), comprising:
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an electromagnetic sensor array (30) including at least two electromagnetic sensors arranged in a known geometrical configuration; and a data processor (220) in electrical communication with the electromagnetic sensor array (30) to receive signals indicative of a sensing of an electromagnetic field by the electromagnetic sensors, wherein the data processor (220) is operable to compute intra-operative relative errors (43) responsive to a movement of the electromagnetic sensor array (30) to numerous estimation positions within an intra-operative electromagnetic field, wherein each intra-operative relative error (43) is an absolute differential between a calibrated distance (40) of an electromagnetic sensor pair and a sensed distance between the electromagnetic sensor pair within the intra-operative electromagnetic field, wherein the data processor (220) is further operable to estimate intra-operative absolute errors (44) responsive to a plotting of the intra-operative relative errors (43) within a pre-operative error map (42) representative of a statistical relationship between pre-operative absolute errors (41) and pre-operative relative errors (41) derived from a movement of the electromagnetic sensor array (30) to numerous measurement positions within a pre-operative electromagnetic field, wherein each intra-operative absolute error (44) is an absolute differential between an estimation position and a sensed position of an electromagnetic sensor within the intra-operative electromagnetic field, wherein each pre-operative absolute error (41) is an absolute differential between a measurement position and a sensed position of an electromagnetic sensor within the pre-operative electromagnetic field, and wherein each pre-operative relative error (41) is an absolute differential between a calibrated distance (40) and a sensed distance between an electromagnetic sensor pair within the pre-operative electromagnetic field. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An electromagnetic tracking method for a tool (90) including a known geometrical configuration of an electromagnetic sensor array (30) of two or more electromagnetic sensors, the method comprising:
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a measurement of a calibrated distance (40) between at least one electromagnetic sensor pair responsive to the electromagnetic sensor array (30) being within a calibration electromagnetic field; a controlled movement of the electromagnetic sensor array (30) within a pre-operative electromagnetic field to various measurement positions; for each electromagnetic sensor, a measurement of a pre-operative absolute error (41) at each measurement position of the electromagnetic sensor, wherein each pre-operative absolute error (41) is an absolute differential between a measurement position and a sensed position of the electromagnetic sensor within the pre-operative electromagnetic field; and for each pairing of electromagnetic sensors, a measurement of a pre-operative relative error (41) at each measurement position, wherein each pre-operative relative error (41) is an absolute differential between a calibrated distance (40) of an electromagnetic sensor paring and a sensed distance of the electromagnetic sensor pair within the pre-operative electromagnetic field. - View Dependent Claims (17, 18, 19, 20)
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Specification