Sensor Calibration for Illumination Alignment in Sterile Environments

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Solution Overview

Problem

Current automated adjustment methods for illumination devices in sterile environments, such as operating rooms, require complex calibration processes to align the illumination area, which are time-consuming and labor-intensive, often necessitating manual handling that breaches sterility.

Innovation Solution

A method involving the use of a sensor device and an illumination device to generate a point of light on a calibration surface, with iterative positioning and detection to establish correspondence points between coordinate systems, allowing for the creation of a transformation matrix for automated alignment, reducing manual intervention and simplifying calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual adjustment of illumination device is used, then alignment can be achieved, but sterility is compromised due to handling requirements

Engineering Contradiction:
Improvealignment adjustmentVSAvoidsterility breach
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces manual mechanical adjustment with an automated robot arm system that performs illumination device alignment without human contact. The robot arm executes adjusting movements in its coordinate system to change the direction of illumination, eliminating the need for personnel to grip or handle the illumination device, thus maintaining sterility while achieving precise alignment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a sensor device as an intermediary between the operator and the illumination device. The sensor device detects the position and orientation of the illumination device and provides feedback to the control system, enabling automated alignment without direct human contact. This intermediary system allows the illumination device to be adjusted automatically while preserving the sterile environment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If automated adjustment via gesture control is used, then sterility is maintained, but calibration complexity increases due to coordinate system transformation requirements

Engineering Contradiction:
Improvesterility maintenanceVSAvoidcalibration process
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses a calibration object with known geometric features (such as a checkerboard pattern or spherical markers) to create a reference model. The sensor device captures images of this calibration object, and the system automatically calculates the transformation matrix by comparing the captured features with the known geometry. This copying approach simplifies calibration by providing clear, measurable reference points that automatically define the coordinate system relationship between the sensor device and the illumination device.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent employs parameter changes in the calibration process by using a calibration object with specifically designed geometric parameters (known positions, orientations, and dimensions). By changing the parameters of the calibration object to have well-defined, measurable features, the system can automatically compute the transformation matrix without complex manual procedures. The calibration process transforms the physical calibration object into digital parameter data that directly defines the coordinate system relationship.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If complex calibration procedures are implemented, then alignment precision is improved, but calibration time increases significantly

Engineering Contradiction:
Improvealignment precisionVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary calibration by placing a calibration object in the workspace before actual operation. The system automatically captures images of the calibration object and computes the transformation matrix in advance, preparing the coordinate system relationship before the illumination device needs to be adjusted. This preliminary action ensures that when alignment is needed, the system already has the necessary transformation data, eliminating time-consuming calibration during actual use.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements self-service calibration where the system automatically performs all calibration operations without manual intervention. The sensor device autonomously captures images of the calibration object, the control system automatically processes the images to extract geometric features, and the transformation matrix is computed and stored automatically. This self-service approach eliminates manual calibration steps while maintaining high precision, significantly reducing calibration time from minutes to seconds.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3010438B1Method for calibrating a sensor device for regulating the alignment of an illumination device and illumination system
Publication Date: 2017.08.09 DRAGERWERK AG
  • EP3010438B1 patent drawingFigure 1
  • EP3010438B1 patent drawingFigure 2
  • EP3010438B1 patent drawingFigure 3

AI summary

The invention relates to a method for calibrating a sensor device (110) for regulating the alignment of an illumination device (120) for modifying the position of an illumination region (200) generated by the illumination device (120) in an illumination direction (A), comprising the following steps: a) generating a light spot (10), emanating from the illumination device (120) in the illumination direction (A), on a calibration surface (310), b) defining a first calibration point (22a) as a center point (M1, M2, M3) of a sphere surface (400) in the illumination direction (120), c) identifying the position of the light spot (10) on the calibration surface (310) using the sensor device (110), d) modifying the alignment of the illumination device (120) along the sphere surface (400), e) repeatedly performing steps c) and d) with the generation of at least three different positions of the light spot (10) on the calibration surface (310), f) determining the distances (D) of the different positions of the light spot (10), g) repeatedly performing steps b) to f) until a stop criterion is reached, h) defining the first calibration point (22a) and the identified position of the light spot (10) on the calibration surface (310) as a correspondence point for the relationship between the coordinate system of the sensor device (110) and the coordinate system of the illumination device (120), i) defining at least one further calibration point (22b, 22c) as a center point (M1, M2, M3) of a sphere surface (400) in the illumination direction (A), j) performing steps b) to h) for the at least one further calibration point (22b, 22c).