LED Color Sensor Calibration Matrix for Cross-Talk Classification

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Solution Overview

Problem

The challenge in surgical robotic systems is the difficulty in accurately classifying colors from light-emitting diodes (LEDs) due to significant cross-talk between color channels in the color sensor, leading to reduced manufacturing yield and classification accuracy.

Innovation Solution

A method involving a calibration process using a 3x3 matrix to convert RGB color space readings to HSV, applying a calibration matrix to filter out cross-talk, and setting proper thresholds for accurate color classification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If color sensors are used to detect LED colors in foot pedals, then visibility and differentiation of pedals is improved, but cross-talk between color channels reduces measurement precision

Engineering Contradiction:
Improvepedal visibilityVSAvoidcolor classification accuracy
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by transforming color measurements from the RGB color space to the HSV color space. This transformation changes the parameters used to represent color, separating hue (color identity) from saturation and value, which helps isolate the cross-talk effect and improve color classification accuracy despite sensor imperfections

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary calibration matrix that acts as a mediator between the raw sensor measurements and the final color classification. This matrix is derived from measurements of known reference colors and transforms the distorted sensor readings into accurate color space coordinates, effectively compensating for the cross-talk between color channels

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If strict color classification thresholds are applied, then classification accuracy is improved, but manufacturing yield decreases due to sensor variations

Engineering Contradiction:
Improvecolor classification accuracyVSAvoidmanufacturing yield
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by performing calibration measurements during the manufacturing process to characterize each sensor's specific response. This pre-characterization data is stored and used during quality control to set individualized acceptance criteria, allowing sensors with normal variations to pass while still maintaining strict color classification standards

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the approach to thresholding by moving from fixed universal thresholds to dynamic thresholds based on each sensor's calibrated response characteristics. This allows the system to accommodate normal manufacturing variations while maintaining accurate color classification, thereby improving manufacturing yield without sacrificing precision

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Improves manufacturing yield and classification accuracy of LEDs in surgical robotic systems by effectively filtering cross-talk and ensuring precise color reproduction.

Implementation Method 1

The LED lights generate different colors allowing the surgeon to differentiate between foot pedals

Methodology Applied
Scientific EffectLight emitting diode: Light Emitting Diode

Implementation Method 2

measuring a color of the at least one LED in a first color space

Methodology Applied
Scientific EffectColor detection: Absorption Spectroscopy

Data Source

PatentEP4255118B1System and method for color sensor characterization, calibration, and threshold-setting
Publication Date: 2025.12.17 COVIDIEN LP
  • EP4255118B1 patent drawingFigure 1
  • EP4255118B1 patent drawingFigure 2
  • EP4255118B1 patent drawingFigure 3~4

AI summary

A method for generating a calibration matrix for light sources includes activating at least one LED of a plurality of multicolor LEDs of a light source and measuring a color of the at least one LED in a first color space. The method also includes scaling the color of the at least one LED relative to the plurality of multicolor LEDs, obtaining a plurality of scaled color measurements, and calculating the calibration matrix based on the plurality of scaled color measurements. A method for calibrating a light source includes activating at least one LED of a plurality of multicolor LEDs of a light source and measuring a color of the at least one LED in a first color space; converting the measured color using a calibration matrix to a calibrated first color space measurement; converting the calibrated first color space measurement to a second color space values; comparing the second color space values to thresholds derived from the calibration matrix; and outputting a calibration failure message in response to the second color space values exceeding the thresholds.