Surgical Microscope Camera Modeling Using Distributed Calibration Poses

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Solution Overview

Problem

Existing calibration methods for surgical microscopes fail to reproducibly map the entire measurement space, leading to inaccuracies and a lack of automated calibration, especially in regions underrepresented by random recordings, and struggle with compensating for assembly and manufacturing tolerances.

Innovation Solution

A method for creating a camera model for surgical microscopes that involves positioning a calibration object in various poses within the measurement space, making recordings, and using optimization algorithms to determine calibration parameters, ensuring the model accurately represents the entire space, allowing for automated and reproducible calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If random recordings of calibration object are used, then calibration process is simple, but measurement precision and reliability of camera model deteriorate in underrepresented regions

Engineering Contradiction:

Improvecalibration process simplicityVSAvoidcamera model accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by pre-defining a set of poses that comprehensively cover the entire measurement space before calibration begins. These poses are calculated in advance based on the measurement space boundaries and camera model requirements, ensuring that all regions are adequately represented without requiring random trial recordings during the calibration process itself.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by making the calibration process adaptive through optimization algorithms. The system dynamically adjusts the camera model parameters by minimizing a cost function that measures the deviation between observed and expected positions of calibration object features across multiple poses, allowing the model to converge to high accuracy regardless of initial conditions.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If manual calibration methods are used, then device complexity is low, but productivity and time consumption worsen

Engineering Contradiction:

Improvecalibration system complexityVSAvoidcalibration speed

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent applies self-service by implementing an automated calibration system that performs all calibration operations without manual intervention. The system automatically positions the calibration object through the measurement space, captures images, processes the data through optimization algorithms, and generates the camera model independently, eliminating the need for manual calibration operations while significantly increasing productivity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical calibration operations with an automated system that uses computational methods. Instead of manual adjustment and observation, the system uses optimization algorithms that computationally minimize the deviation between observed and expected feature positions, substituting mechanical/manual processes with automated computational ones to improve efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If comprehensive pose coverage is achieved, then camera model reliability improves, but loss of time and productivity worsen

Engineering Contradiction:

Improvecamera model representativenessVSAvoidcalibration duration

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating an optimal set of poses that comprehensively cover the measurement space before calibration begins. This predefined pose set ensures complete spatial coverage while minimizing the number of required recordings, thus achieving high reliability without excessive time consumption.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies partial action by using a strategically selected subset of poses that are sufficient to fully characterize the camera model across the entire measurement space. Rather than recording at every possible position, the system identifies and uses only the critical poses needed for accurate model generation, avoiding unnecessary time expenditure while maintaining comprehensive coverage.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12363273B2Method for creating a camera model for a camera of a surgical microscope, and arrangement having a surgical microscope

Publication Date: 2025.07.15 CARL ZEISS MEDITEC AG

AI summary

A method for creating a camera model for a camera of a surgical microscope includes positioning a calibration object in an initial pose in an observation region of the camera, determining a pose delta for reaching a first pose for the calibration object in a measurement space of the camera starting from the initial pose, positioning the calibration object in the first pose in accordance with the determined pose delta, making a recording of the calibration object in the first pose with the camera, positioning the calibration object in at least one further pose, making a recording of the calibration object in the at least one further pose, and creating a camera model based on the recordings made, the first pose and the at least one further pose being chosen with a distribution in the measurement space such that a camera model is obtained which represents the entire measurement space.