# US 12,602,830 B2 · Method for calibrating cameras of a multichannel medical visualization system and medical visualization system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,602,830 B2 - Document ID: US12602830B2 - Status: Granted - Kind: B2 - Application number: 18/478,968 - Filed: 2023-09-29 - Published: 2024-04-11 - Granted: 2026-04-14 - Earliest claimed: 2022-10-07 - Assignees: Carl Zeiss Meditec AG - Applicants: Carl Zeiss Meditec AG - Inventors: Richard Baeumer; Marco Woerner; Henrike Von Huelsen - Web page: https://patentgrep.com/patent/US12602830B2 ## CPC - G06T 7/80: Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration - G06T 7/85: {Stereo camera calibration} - G06T 3/40: Scaling of whole images or parts thereof, e.g. expanding or contracting - G06T 2207/10056: Microscopic image - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract A method and a system for calibrating cameras of a multichannel medical visualization system, including capturing a capturing region respectively imaged via channels of the multichannel medical visualization system by a respective camera, determining a magnification center for each of the channels, setting at least two magnification levels of a common mechanical magnification optical unit, identifying an image region which does not move or which moves the least across the magnification levels for each of the channels in image representations which are captured, and, proceeding from the respectively determined magnification centers, defining an image portion for each of the channels in the captured image representations with the respectively identified magnification center as the center, and restricting an output of the captured image representations at all magnification levels to the image portion defined for the respective channel. ## Claims ### Claim 1 A method for calibrating cameras of a multichannel medical visualization system, the method comprising: capturing a capturing region respectively imaged via channels of the multichannel medical visualization system by a respective camera, determining a respective magnification center for each of the channels, setting at least two magnification levels of a common mechanical magnification optical unit, identifying an image region which does not move or which moves the least across the magnification levels for each of the channels in image representations which are captured at each of the at least two magnification levels by the respective camera, proceeding from the respectively determined magnification centers, defining an image portion for each of the channels that is in the captured image representations with the respectively identified magnification center as the center, and restricting an output of the captured image representations at all magnification levels to the image portion defined for the respective channel. ### Claim 2 (depends on 1) The method according to claim 1, wherein dimensions of the image portions are defined for all directions taking into consideration dimensions of the image representation provided by a respective image sensor of the cameras. ### Claim 3 (depends on 1) The method according to claim 1, wherein the defined image portions are chosen to have the same size. ### Claim 4 (depends on 1) The method according to claim 1, wherein a relative twist of the captured image representations of the channels is also determined with respect to one another, wherein at least one feature is identified in the captured image representations and a movement direction of a movement, implemented over the at least two magnification levels, of the at least one identified feature in the captured image representations is determined and evaluated, and wherein the determined relative twist is corrected at least for the defined image portions by adapting at least one of the image portions and/or by image processing. ### Claim 5 (depends on 1) The method according to claim 1, wherein an absolute twist is also determined for at least one channel on the basis of captured image representations, wherein the at least one channel of the multichannel visualization system is displaced by means of at least one actively movable axis of the visualization system, and wherein at least one of the defined image portions is additionally or alternatively corrected by adapting the image portion and/or by image processing taking into consideration the determined absolute twist. ### Claim 6 (depends on 1) The method according to claim 1, wherein a reference calibration object is used when determining the magnification centers and/or the twist(s). ### Claim 7 (depends on 1) The method according to claim 1, wherein the calibration is performed automatically following a start-up and/or before a shutdown of the medical visualization system and/or at given time intervals and/or at given times and/or after a given number of operating cycles. ### Claim 8 (depends on 1) The method according to claim 1, wherein the calibration is carried out during the normal operation of the medical visualization system, if a magnification is changed and at least two magnification levels are set. ### Claim 9 (depends on 1) The method according to claim 1, wherein the magnification centers and/or the twist(s) are determined by an artificial intelligence method and/or by determination of the optical flow. ### Claim 10 (depends on 1) The method according to claim 1, wherein a maintenance request and/or alignment request is generated and output if at least one of the defined image portions is adjacent to or goes beyond an edge of the image representation provided by an image sensor of the respective camera. ### Claim 11 (depends on 1) The method according to claim 1, wherein at least three magnification levels are set, wherein magnification centers are determined in each case by in each case taking account of at least two adjacent magnification levels of the at least three magnification levels, and wherein a scatter of the determined magnification centers is evaluated. ### Claim 12 (depends on 1) The method according to claim 1, wherein at least three magnification levels are set, wherein magnification centers are determined in each case by in each case taking account of at least two adjacent magnification levels of the at least three magnification levels, and wherein the image portions of the channels are defined in each case proceeding from a set magnification level and the magnification centers determined therefor in each case if different magnification centers are determined at different magnification levels and/or if a scatter of the determined magnification centers exceeds a given limit value. ### Claim 13 (depends on 1) The method according to claim 1, wherein at least one same feature is recognized in the image portions respectively defined for the channels, wherein a respective position of the at least one recognized same feature is determined in the respective image portions of the channels, and wherein a deviation between the positions determined for the channels in each case is determined and evaluated. ### Claim 14 (depends on 1) The method according to claim 1, wherein the medical visualization system is in the form of a stereoscopic medical visualization system with at least two channels. ### Claim 15 A medical visualization system, comprising: a plurality of channels for capturing and imaging a capturing region, a camera for each of the plurality of channels, configured to capture the respective capturing region imaged by way of the channel, a common mechanical magnification optical unit, and a control device, wherein the control device is configured, for calibration purposes, to determine a respective magnification center for each of the channels and control the common mechanical magnification optical unit in such a way that at least two magnification levels are set, and to identify an image region which does not move or which moves the least across the magnification levels for each of the channels in image representations which are captured at the at least two magnification levels by means of the respective camera, in each case proceeding from the respectively determined magnification centers, to define an image portion for each of the channels in the captured image representations with the respectively identified magnification center as the center, and to restrict an output of the captured image representations at all magnification levels to the image portion defined for the respective channel.