2D Barcode Recognition via Image Rectification

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Solution Overview

Problem

Automatic identification and evaluation of 2-D barcodes in real-world scenarios using ordinary cameras or mobile phone cameras are challenging due to factors like illumination variation, rotation, and perspective distortion, making barcode localization difficult.

Innovation Solution

The system processes input images of 2-D barcodes to compensate for illumination variations, convert them into binary images, and rectify the barcodes into a predetermined square format, generating a 2-D barcode symbol matrix that can be recognized by a symbol recognition module.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a charge coupled camera capturing device is used to capture 2-D barcodes in real-world scenarios, then the system can capture digital images of 3-D scenes, but the images suffer from illumination variation, rotation, and perspective distortion that make barcode localization difficult

Engineering Contradiction:
Improveability to capture barcodes in real-world scenariosVSAvoidbarcode localization difficulty
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The system performs preliminary actions by capturing an image of the 2-D barcode before processing it. The captured image is then rectified to generate a warped image with corrected perspective distortion, and finally processed to generate the barcode symbol matrix. This preliminary capture step enables the system to handle real-world scenarios while the subsequent processing steps correct for the difficulties mentioned.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes parameters by transforming the captured image through rectification to generate a warped image. This parameter transformation corrects perspective distortion and illumination variation, converting the difficult-to-localize barcode in the original image into an easier-to-process barcode in the warped image with standardized geometry and lighting.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the captured digital image is processed to compensate for illumination variations and perspective distortion, then barcode recognition accuracy improves, but the processing complexity and time increase

Engineering Contradiction:
Improvebarcode recognition accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The processing pipeline is segmented into distinct stages: capturing the image, rectifying the image to compensate for distortion and illumination, generating the barcode symbol matrix, and presenting the data. This segmentation allows each stage to be optimized independently and enables parallel processing of different operations, reducing overall processing time while maintaining accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system replaces complex manual barcode reading mechanisms with automated image processing algorithms. Instead of requiring physical alignment or manual scanning, the system uses computational methods to rectify images and extract barcode data, significantly reducing processing time while improving accuracy.

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

3Manufacturing precision

If the 2-D barcode is rectified to remove non-uniform lighting and perspective distortion, then the barcode can be accurately segmented and converted to a matrix array, but the computational resources and processing steps increase

Engineering Contradiction:
Improvebarcode segmentation precisionVSAvoidprocessing system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The rectified image serves as an intermediary between the captured image and the final barcode symbol matrix. This intermediary step corrects perspective distortion and illumination variation, creating a standardized representation that simplifies the subsequent matrix generation process. The rectified image acts as a bridge that reduces the complexity of direct processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system applies parameter changes through rectification to transform the captured image into a warped image with corrected geometry and lighting. This parameter transformation simplifies the segmentation process by creating uniform conditions, reducing the computational complexity required for accurate barcode extraction while maintaining high segmentation precision.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS7780084B22-D barcode recognition
Publication Date: 2010.08.24 MICROSOFT TECHNOLOGY LICENSING LLC
  • US7780084B2 patent drawing
  • US7780084B2 patent drawing
  • US7780084B2 patent drawing

AI summary

Systems and methods for 2-D barcode recognition are described. In one aspect, the systems and methods use a charge coupled camera capturing device to capture a digital image of a 3-D scene. The systems and methods evaluate the digital image to localize and segment a 2-D barcode from the digital image of the 3-D scene. The 2-D barcode is rectified to remove non-uniform lighting and correct any perspective distortion. The rectified 2-D barcode is divided into multiple uniform cells to generate a 2-D matrix array of symbols. A barcode processing application evaluates the 2-D matrix array of symbols to present data to the user.