Color-Coded Location Symbols for Reliable Indoor Image Decoding

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Solution Overview

Problem

Existing methods for providing navigation and location-based information in enclosed environments, such as indoor spaces, are inadequate due to reliance on GPS which is unreliable indoors, and existing image-based encoding schemes like QR codes are difficult to read and lead to user confusion.

Innovation Solution

The development of novel computer-readable symbols comprising polygons with distinct colors, encoded using a specific color scheme and tessellation patterns, allowing reliable decoding by mobile devices regardless of lighting conditions and size, and a system for distributing these symbols to provide location-based information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional barcodes or QR codes are used for encoding location information, then the encoding can be implemented with simple monochrome patterns, but the symbols are difficult to read and lead to user confusion especially in enclosed environments

Engineering Contradiction:
Improveease of symbol productionVSAvoidease of symbol reading
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent applies color changes by using multiple distinct colors (red, green, blue, cyan, magenta, yellow) to represent different binary values in the color elements. This color-based encoding scheme makes the symbols more visually distinct and easier to read compared to monochrome barcodes, while still being manufacturable through standard printing processes that apply cyan, magenta, and yellow pigments to a substrate.

Inventive Principle:
Principle #32Color changes

2Reliability

If GPS is used for navigation in enclosed environments, then outdoor navigation can be provided, but GPS is unreliable indoors and cannot provide accurate location information

Engineering Contradiction:
Improvereliability of location informationVSAvoidapplicability to enclosed environments
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the GPS satellite-based electromagnetic positioning system with a local visual encoding system using color-coded symbols that can be read by image sensors on mobile devices. This substitution enables reliable location identification in enclosed environments where GPS signals are unavailable, while the system can still work outdoors by placing the same type of symbols in those environments.

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

3Loss of information

If existing image-based encoding schemes are used, then information can be encoded in a machine-readable form, but the schemes are difficult to read and cause user confusion

Engineering Contradiction:
Improveinformation encoding capabilityVSAvoiddifficulty of symbol detection
Core Design Contradiction:
Loss of informationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses color changes with six distinct colors representing different binary values (00, 01, 10, 11 for red, green, blue and their combinations). This color-based approach enhances information encoding capability while improving detectability through the use of distinct, visually separable colors that are easier for image sensors to differentiate compared to subtle variations in monochrome patterns.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent changes the parameter of color intensity and hue to encode information. By using six distinct colors with different RGB values, the system increases both the information density and the ease of detection. The color elements are defined by specific intensity characteristics in the sRGB color space, making them easier to detect and distinguish than traditional binary black-and-white patterns.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If color-based encoding is implemented to improve readability, then symbol recognition can be enhanced, but the color elements may not be reliably distinguished under various lighting conditions

Engineering Contradiction:
Improveease of symbol identificationVSAvoidreliability of color detection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent defines specific intensity characteristics for each color element in the sRGB color space, with each primary color (red, green, blue) having intensity greater than twice the other two colors. This parameter specification ensures reliable color distinction under various lighting conditions by creating sufficient intensity margins that are robust to illumination variations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates a verification process where the system checks whether the detected color elements satisfy the required intensity relationships. This feedback mechanism allows the decoding system to verify color identification reliability and request re-reading if the color thresholds are not met, ensuring accurate symbol recognition regardless of lighting conditions.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3509015B1A method for encoding information, a tangible medium having a symbol produced thereon using the method, and an information system
Publication Date: 2021.01.27 SODYO
  • EP3509015B1 patent drawingFigure 1
  • EP3509015B1 patent drawingFigure 2
  • EP3509015B1 patent drawingFigure 3~4

AI summary

A method for encoding information, comprising: specifying a digital value; and producing a symbol that encodes the specified digital value in a set of color elements having different, respective colors, to be identified in an image of the symbol as red, green, blue, cyan, magenta and yellow color elements, respectively, wherein the symbol is produced by applying cyan, magenta and yellow pigments to a substrate so as to produce the color elements, such that the color elements exhibit the following red, green, and blue intensity characteristics when measured in an sRGB color space: for the red color elements, the red intensity is greater than twice the blue and green intensities; for the green color elements, the green intensity is greater than twice the red and blue intensities; for the blue color elements, the blue intensity is greater than twice the red and green intensities; for the cyan color element, the blue and green intensities are both greater than twice the red intensity; for the magenta color element, the red and blue intensities are both greater than twice the green intensity; and for the yellow color element, the red and green intensities are both greater than twice the blue intensity.