Weft-Knitted QR Code Mapping with Stitch-Shape Compensation

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Solution Overview

Problem

Existing solutions for implementing QR codes on knitted fabrics fail to ensure reliable reading by standard optical readers and mobile device applications due to the non-square shape of knit stitches, and they are not reproducible at an industrial level.

Innovation Solution

A method to map each square of a QR code onto a weft knitted base element composed of a specific number of stitches, compensating for the non-square shape of knit stitches, using a combination of base elements with defined numbers of courses and wales, enabling correct reading by standard optical readers and mobile applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a QR code is implemented on knitted fabric using conventional methods, then the QR code can be produced on fabric, but the reading reliability by standard optical readers and mobile devices is poor due to the non-square shape of knit stitches

Engineering Contradiction:
ImproveQR code reading reliabilityVSAvoidSquare shape precision of QR code modules
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention divides each QR code module into multiple knit stitches arranged in a specific pattern. Instead of using a single stitch or a simple rectangular block, each module is segmented into a configuration of stitches that collectively form a square shape, compensating for the inherent non-square nature of individual knit stitches.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses an asymmetric arrangement of knit stitches within each module to compensate for the asymmetric distortion caused by the knitting process. By carefully positioning stitches with different numbers of courses and wales, the method creates a visually square appearance despite the underlying asymmetric stitch structure.

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If a QR code is implemented on knitted fabric with standard methods, then production can be simplified, but the QR code cannot be reliably reproduced at an industrial level

Engineering Contradiction:
ImproveQR code production simplicityVSAvoidIndustrial reproduction reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the parameters of the knit stitch configuration, specifically using a defined number of courses different from a defined number of wales in each base element. This parameter adjustment compensates for the natural distortion in knitting and enables reliable industrial reproduction of square-shaped QR code modules.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a QR code is implemented on knitted fabric without compensating for stitch shape, then the implementation process is simpler, but the QR code does not maintain a square appearance

Engineering Contradiction:
ImproveQR code implementation complexityVSAvoidSquare appearance of QR code modules
Core Design Contradiction:
Device complexityVSShape

Solution Approach 1:

The invention applies preliminary action by pre-calculating and pre-defining the specific stitch configurations needed to create square-shaped modules. The method establishes predetermined patterns of courses and wales that automatically compensate for distortion, eliminating the need for post-production adjustments while maintaining square appearance.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4272117B1Method for implementing a QR code in weft knitted fabric
Publication Date: 2025.08.13 POLITECNICO DI MILANO
  • EP4272117B1 patent drawingFigure 1
  • EP4272117B1 patent drawingFigure 2
  • EP4272117B1 patent drawingFigure 3A

AI summary

It is disclosed a method for implementing a knitted QR code. The method comprises the steps of generating a sample QR code (1) comprising a plurality of modules having at least two different colours, comprises defining a base element (1-2.1a; 2-2.1a) of a weft knitted fabric, wherein each base element comprises a number of courses different from the number of wales, and comprises converting each module of the plurality of modules of the sample QR code into a respective base element of the weft knitted fabric, thereby generating the weft knitted QR code (10).