2D Graphic Code Reading with Calibration Zones

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing 2D graphic codes, particularly color graphic codes, face challenges in reliable and precise reading due to variations in acquisition conditions such as hardware and software configurations, lighting conditions, and heterogeneity in lighting, leading to inconsistent and error-prone results.

Innovation Solution

The method employs spatial interpolation to estimate the theoretically observable color of each color base on the surface of the 2D graphic code, using calibration zones to normalize readings across different devices and lighting conditions, ensuring uniform and accurate data retrieval even under complex lighting scenarios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If 2D graphic codes use high symbol density to increase information storage capacity, then the amount of information that can be stored increases, but the reliability and accuracy of reading the code deteriorates due to device and lighting variations

Engineering Contradiction:
Improveinformation storage capacityVSAvoidreading reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-defining calibration zones with known reference colors at specific positions within the 2D graphic code structure. These calibration zones are embedded during code generation to establish a reference framework before the actual reading process occurs, enabling the system to compensate for acquisition variations during decoding

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements parameter changes by dynamically adjusting color interpretation parameters based on measurements from calibration zones. The system measures actual colors in calibration zones, compares them to reference colors, and uses the derived correction factors to adjust color readings in data zones, thereby maintaining reading reliability across varying acquisition conditions

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If color is introduced into 2D graphic codes to increase information density, then the information density increases, but reading consistency deteriorates due to color variations from different devices and lighting conditions

Engineering Contradiction:
Improveinformation densityVSAvoidcolor measurement consistency
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent applies local quality by assigning different functional roles to different zones within the 2D graphic code. Calibration zones contain known reference colors used exclusively for measurement correction, while data zones contain the actual information-encoded colors. This spatial differentiation of quality and function enables accurate color measurement despite device and lighting variations

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements feedback by using the measured color values from calibration zones to generate correction factors that are then applied to the color readings in data zones. This closed-loop approach continuously adjusts color interpretation based on actual acquisition conditions, significantly improving color measurement consistency across different devices and lighting scenarios

Inventive Principle:
Principle #23Feedback

3Reliability

If traditional black and white barcodes are used, then reading reliability is maintained, but information storage capacity is limited

Engineering Contradiction:
Improvereading reliabilityVSAvoidinformation storage capacity
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies dimensionality change by transitioning from traditional one-dimensional black and white barcodes to two-dimensional graphic codes with multiple colors. This dimensional expansion allows significantly more information to be encoded in the same physical space while maintaining reading reliability through the integrated calibration zone system that compensates for color measurement variations

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

Data Source

PatentEP3945450B1Graphic code reading
Publication Date: 2024.08.28 IDEMIA FRANCE SAS
  • EP3945450B1 patent drawingFigure 1
  • EP3945450B1 patent drawingFigure 2~3
  • EP3945450B1 patent drawingFigure 4

AI summary

The invention relates to the reading, by a reading device (DV1), of a 2D graphic code (CG1) comprising zones (Z) including data zones encoding information from real colors in a color base (BS1) and calibration zones presenting a predefined reference color, the method comprising: optical acquisition of the 2D graphic code under common acquisition conditions (CD1) to obtain image data (DT1); measurement of the observable color (CLB) in the calibration zones; spatial interpolation, from the observable colors (CLB) in the calibration zones, to estimate the theoretically observable color for each color of the base in the 2D graphic code; and classification from the spatial interpolation to determine the real color of the analyzed data zones.