Multicolor Camera Display Calibration

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Solution Overview

Problem

Electronic displays exhibit variability in tone-response and color-response due to manufacturing inconsistencies, leading to inefficient calibration processes that are time-consuming and only measure one color at a time, resulting in incomplete and inaccurate calibration data.

Innovation Solution

A multicolor camera with three charge-coupled devices (3CCD) is used to capture and calibrate color test patterns simultaneously, eliminating color crosstalk and enabling rapid, accurate measurement of RGB bands, and applying spectral-based calibration to generate correction matrices for improved display homogeneity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a spectrometer or color meter is used for display calibration, then measurement precision is improved, but productivity deteriorates due to sequential single-color measurement taking up to 48 minutes

Engineering Contradiction:
Improvecolor measurement precisionVSAvoidcalibration speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the spectral measurement function into three separate CCD sensors, each dedicated to capturing a specific wavelength band (red, green, blue). This segmentation allows simultaneous measurement of all three color channels, eliminating the sequential measurement bottleneck while maintaining spectral-based measurement precision through dedicated sensors for each color range.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from sequential temporal measurement (one wavelength at a time) to parallel spatial measurement by using three separate CCD sensors that simultaneously capture different wavelength bands. This dimensional change from time-sequential to space-parallel architecture enables full-color calibration in a single capture event.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If a spectrometer measures one wavelength at a time, then measurement precision for individual wavelengths is improved, but loss of time increases due to sequential measurement requirements

Engineering Contradiction:
Improvespectral measurement precisionVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The spectral measurement task is segmented across three independent CCD sensors, each optimized for a specific wavelength range. This allows simultaneous capture of red, green, and blue spectral information without sequential delays, maintaining the precision benefits of spectral measurement while eliminating time loss through parallel processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables continuous simultaneous measurement of all three color channels through three parallel CCD sensors, eliminating the stop-and-go sequential measurement process. All wavelength bands are captured in one continuous action, removing idle time between measurements while preserving spectral precision.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If display calibration is performed at multiple colors sequentially, then measurement precision across color spectrum is improved, but productivity deteriorates due to repeated measurements

Engineering Contradiction:
Improvecolor response precisionVSAvoidcalibration throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the color measurement function into three dedicated CCD sensors, each capturing a specific color band simultaneously. This eliminates the need for repeated sequential measurements at different colors, as all color information is captured in parallel in a single measurement event, maintaining comprehensive color precision while maximizing calibration throughput.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges the measurement of all three color channels into a single simultaneous capture operation using three synchronized CCD sensors. Instead of performing separate measurements for red, green, and blue channels, all color data is acquired together in one action, improving productivity while maintaining precision through the combined spectral coverage.

Inventive Principle:
Principle #5Merging (Combining)

4Device complexity

If a single spot measurement is performed, then device complexity is reduced, but measurement precision deteriorates due to inability to capture display non-uniformity

Engineering Contradiction:
Improvemeasurement system complexityVSAvoiddisplay homogeneity measurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent creates a universal measurement system where the three-CCD camera simultaneously performs both spot measurement and spatial uniformity assessment. The same parallel imaging system used for color measurement also captures display non-uniformity across different regions, adding the multi-functionality of homogeneity detection without significantly increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent adds the spatial dimension to color measurement by using the parallel CCD architecture to capture both color information and spatial non-uniformity simultaneously. This dimensional enhancement allows the system to measure display homogeneity across multiple locations without requiring separate measurement devices, improving precision while maintaining reasonable complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This method significantly reduces calibration time and enhances color accuracy, achieving average color errors below one CIE DE2000 unit across multiple colors and backlight settings, ensuring precise color representation.

Implementation Method 1

a spectrally calibrated multicolor camera to capture images of a multicolor calibration pattern

Methodology Applied
Scientific EffectSpectral separation: Dispersion (of waves)

Implementation Method 2

a multicolor camera having three charge coupled devices (3CCD) is used to evaluate color test patterns

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP2751799B1Fast calibration of displays using spectral-based colorimetrically calibrated multicolor camera
Publication Date: 2022.09.14 QUALCOMM INC
  • EP2751799B1 patent drawingFigure 1
  • EP2751799B1 patent drawingFigure 2
  • EP2751799B1 patent drawingFigure 3

AI summary

Described are a system and method to calibrate displays using a spectral-based colorimetrically calibrated multicolor camera. Particularly, discussed are systems and methods for displaying a multicolor calibration pattern image on a display unit, capturing the multicolor calibration pattern image with a multicolor camera having a plurality of image sensors, with each image sensor configured to capture a predetermined color of light, comparing a set of reference absolute XYZ coordinates of a set of colors from the multicolor calibration pattern with a set of measured XYZ color coordinates captured using the colorimetrically calibrated camera, and calibrating the display unit based on the comparison between the reference coordinates and the measured coordinates.