# US 11,896,286 B2 · Magnetic and optical catheter alignment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,896,286 B2 - Document ID: US11896286B2 - Status: Granted - Kind: B2 - Application number: 16/536,720 - Filed: 2019-08-09 - Published: 2021-02-11 - Granted: 2024-02-13 - Earliest claimed: 2019-08-09 - Assignees: Biosense Webster (Israel) Ltd. - Applicants: Biosense Webster (Israel) Ltd. - Inventors: Vadim Gliner; Assaf Govari - Web page: https://patentgrep.com/patent/US11896286B2 ## CPC - A61B 18/14: Probes or electrodes therefor - A61B 1/00009: {of image signals during a use of endoscope} - A61B 1/00057: {provided with means for testing or calibration} - A61B 1/00097: {Sensors} - A61B 1/045: Control thereof - A61B 1/05: characterised by the image sensor, e.g. camera, being in the distal end portion - A61B 1/0676: {at distal tip of an endoscope} - A61B 5/0084: {for introduction into the body, e.g. by catheters (A61B5/1459 takes precedence)} - A61B 5/062: {using magnetic field} - A61B 5/6852: {Catheters} - G06T 7/0012: {Biomedical image inspection} - A61B 2034/2051: {Electromagnetic tracking systems} - A61B 2560/0233: Optical standards - A61B 2562/0223: Magnetic field sensors - G06T 2207/30021: Catheter; Guide wire - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract In one embodiment, an apparatus for calibrating a probe that includes an image sensor and a magnetic field sensor, includes a jig configured to hold the probe, a magnetic field generator configured to generate at least one magnetic field having a predefined direction in alignment with the jig, an optical target aligned with the jig so that the image sensor in the probe is able to capture an image of the optical target while the probe is held in the jig, and processing circuitry configured to receive from the probe a signal output by the magnetic field sensor in response to the at least one magnetic field and the image captured by the image sensor while the probe is held in the jig, and to calibrate an alignment of the image sensor relative to the magnetic field sensor responsively to the received signal and the received image. ## Claims ### Claim 1 An apparatus for calibrating a probe that includes an image sensor and a magnetic field sensor, the apparatus comprising: a magnetic field generator being configured to generate at least one magnetic field having a predefined direction in alignment with a jig; the jig being configured to hold the probe such that the axes of the magnetic field sensor are substantially aligned with the respective axes of the magnetic coordinate frame based on the predefined direction of the magnetic field; an optical target aligned with the jig, based on a central alignment feature, so that the image sensor in the probe is able to capture an image of the optical target while the probe is held in the jig, the optical target being configured to be rotated around the central alignment feature; and processing circuitry configured to receive from the probe a signal output by the magnetic field sensor in response to the at least one magnetic field and the image captured by the image sensor while the probe is held in the jig, and to calibrate an alignment of the image sensor relative to the magnetic field sensor responsively to the received signal and the received image. ### Claim 2 (depends on 1) The apparatus according to claim 1, the processing circuitry being configured to calibrate an alignment of the magnetic field sensor to the at least one magnetic field generated by the magnetic field generator responsively to the received signal. ### Claim 3 (depends on 2) The apparatus according to claim 2, the processing circuitry being configured to store the alignment of the image sensor relative to the magnetic field sensor and the alignment of the magnetic field sensor to the at least one magnetic field in a storage device comprised in the probe. ### Claim 4 (depends on 1) The apparatus according to claim 1, the processing circuitry being configured to compute a sensitivity of the magnetic field sensor responsively to the received signal. ### Claim 5 (depends on 1) The apparatus according to claim 1, the optical target comprising multiple alignment features; the received image includes at least some alignment features of the multiple alignment features; and the processing circuitry being configured to compute an optical-aberration correction for the image sensor responsively to respective positions of respective ones of the at least some alignment features in the received image. ### Claim 6 (depends on 5) The apparatus according to claim 5, the processing circuitry being configured to compute the optical-aberration correction for the image sensor responsively to a curvature of at least one line defined by the respective positions of respective ones of the at least some alignment features in the received image. ### Claim 7 (depends on 6) The apparatus according to claim 6, the optical target including multiple alternating rectangular sections; and the processing circuitry being configured to find respective boundaries between respective ones of the rectangular sections corresponding with respective ones of the multiple alignment features. ### Claim 8 (depends on 7) The apparatus according to claim 7, a central boundary between ones of the rectangular sections corresponding with the central alignment feature of the multiple alignment features, the processing circuitry being configured to calibrate the alignment of the image sensor relative to the magnetic field sensor responsively to the position of the central alignment feature in the received image. ### Claim 9 (depends on 8) The apparatus according to claim 8, the processing circuitry being configured to: receive a plurality of respective images captured by the image sensor of the optical target at multiple respective rotational positions of the optical target; and compute the optical-aberration correction for the image sensor responsively to the respective positions of respective ones of the at least some alignment features in the received respective images. ### Claim 10 (depends on 1) The apparatus according to claim 1, the magnetic field generator comprising three calibration-coil sets respectively aligned with three orthogonal axes of a magnetic coordinate frame; the magnetic field sensor including three position coils; and the processing circuitry being configured to: actuate the calibration-coil sets to generate magnetic fields for detection by the position coils; and calibrate, for each of the position coils, an alignment with the magnetic coordinate frame responsively to signals received from position coils. ### Claim 11 A method for calibrating a probe that includes an image sensor and a magnetic field sensor, the method comprising: disposing the probe in a jig; generating at least one magnetic field having a predefined direction in alignment with the jig; rotating an optical target relative to the probe and a portion of the jig; capturing with the image sensor an image of the optical target aligned with the jig while the probe is held stationary in the jig, receiving from the probe a signal output by the magnetic field sensor in response to the at least one magnetic field and the image captured by the image sensor while the probe is held in the jig; and calibrating an alignment of the image sensor relative to the magnetic field sensor responsively to the received signal and the received image. ### Claim 12 (depends on 11) The method according to claim 11, further comprising calibrating an alignment of the magnetic field sensor to the at least one magnetic field responsively to the received signal. ### Claim 13 (depends on 12) The method according to claim 12, further comprising storing the alignment of the image sensor relative to the magnetic field sensor and the alignment of the magnetic field sensor to the at least one magnetic field in a storage device comprised in the probe. ### Claim 14 (depends on 11) The method according to claim 11, further comprising computing a sensitivity of the magnetic field sensor responsively to the received signal. ### Claim 15 (depends on 11) The method according to claim 11, the optical target comprising multiple alignment features; the received image including at least some alignment features of the multiple alignment features; and the method further comprising computing an optical-aberration correction for the image sensor responsively to respective positions of respective ones of the at least some alignment features in the received image. ### Claim 16 (depends on 15) The method according to claim 15, the computing of the optical-aberration correction being performed responsively to a curvature of at least one line defined by the respective positions of respective ones of the at least some alignment features in the received image. ### Claim 17 (depends on 16) The method according to claim 16, the optical target including multiple alternating rectangular sections; and the method further comprises finding respective boundaries between respective ones of the rectangular sections corresponding with respective ones of the multiple alignment features. ### Claim 18 (depends on 17) The method according to claim 17, a central boundary between ones of the rectangular sections corresponding with a central alignment feature of the multiple alignment features; and calibrating the alignment of the image sensor relative to the magnetic field sensor being performed responsively to the position of the central alignment feature in the received image. ### Claim 19 (depends on 18) The method according to claim 18, further comprising: rotating the optical target around the central alignment feature to multiple rotational positions; and receiving a plurality of respective images captured by the image sensor of the optical target at respective ones of the multiple rotational positions of the optical target, and the computing the optical-aberration correction for the image sensor being performed responsively to the respective positions of respective ones of the at least some alignment features in the received respective images. ### Claim 20 (depends on 11) The method according to claim 11, further comprising: actuating three calibration-coil sets respectively aligned with three orthogonal axes of a magnetic coordinate frame to generate magnetic fields for detection by three position coils of the magnetic field sensor; and calibrating, for each of the position coils, an alignment with the magnetic coordinate frame responsively to signals received from position coils. ### Claim 21 A method for using an apparatus to calibrate a probe, the probe comprising an image sensor and a magnetic field sensor, the apparatus comprising: a jig; a magnetic field generator; an optical target aligned with the jig, based on a central alignment feature, the optical target being configured to be rotated around the central alignment feature; and processing circuitry; the method comprising: disposing the probe in the jig; generating at least one magnetic field having a predefined direction in alignment with the jig, the jig holding the probe such that the axes of the magnetic field sensor are substantially aligned with the respective axes of the magnetic coordinate frame based on the predefined direction of the at least one magnetic field; capturing with the image sensor the image of the optical target aligned with the jig while the probe is held stationary in the jig; receiving from the probe the signal output by the magnetic field sensor in response to the at least one magnetic field and the image captured by the image sensor while the probe is held in the jig, the signal being received by the processing circuitry; and calibrating the alignment of the image sensor relative to the magnetic field sensor responsively to the received signal and the captured image, the calibrating being performed by the processing circuitry.