Imaging Scanner Border Search for Accurate Form Extent

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Solution Overview

Problem

Conventional imaging-based bar code readers face challenges in accurately determining the extent of an imaged form or document due to large size differences between the target bar code and the form, leading to magnified errors in extrapolating the form's bounds from the bar code's center, especially when small pixel errors are magnified during the scaling process.

Innovation Solution

An imaging-based system and method that utilizes a target bar code of known size and location within a form to identify the border of the form by determining reference points within the bar code and the form, allowing for accurate identification and saving of the imaged border within a captured image frame.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the target bar code is used as the reference to extrapolate the form's bounds, then the bar code reading function is achieved, but the measurement precision of the form's extent deteriorates due to magnified errors from size differences

Engineering Contradiction:
Improvebar code reading capabilityVSAvoidform extent determination accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces a border detection mechanism as an intermediary between the bar code identification and the form extent determination. Instead of directly extrapolating from the bar code, the system first detects the border surrounding the form, which serves as a more reliable reference for determining the form's actual bounds and reduces error magnification

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the form identification process into distinct stages: first identifying the bar code within the form, then separately detecting the border that surrounds the form. This segmentation allows each detection task to be optimized independently, with the border detection providing accurate spatial boundaries without being affected by the size disparity between the bar code and the entire form

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If the form size is much larger than the bar code size, then the form contains more information, but the error magnification during scaling increases

Engineering Contradiction:
Improveform information contentVSAvoidscaling error magnitude
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The border acts as an intermediary reference that bridges the gap between the small bar code and the large form. By detecting the border that directly surrounds the form, the system obtains accurate spatial boundaries without needing to perform error-prone scaling operations from the bar code dimensions to the form dimensions

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent shifts from a one-dimensional scaling approach (scaling from bar code size to form size) to a two-dimensional detection approach by identifying the border that directly outlines the form. This dimensional shift allows the system to determine form boundaries through direct detection rather than through error-prone proportional scaling

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

3Device complexity

If conventional extrapolation methods are used from bar code center, then the process is simple, but the accuracy of border identification deteriorates

Engineering Contradiction:
Improveprocessing algorithm simplicityVSAvoidborder location accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The border detection serves as an intermediary step that provides accurate spatial reference information. Rather than directly extrapolating from the bar code center, the system detects the border that surrounds the form, which gives precise boundary information without requiring complex extrapolation calculations

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs border detection as a preliminary action before final form identification. By first detecting the border that surrounds the form, the system establishes accurate spatial boundaries that can then be used to precisely identify the form extent, improving overall accuracy before final processing

Inventive Principle:
Principle #10Preliminary action

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 approach enables precise identification of the acquisition area's extent, reducing errors and ensuring accurate imaging and decoding of the form, even when the bar code is significantly smaller than the form, by using information about the bar code's size and location to search for and identify the form's border.

Implementation Method 1

If the target object is within the field of view of the camera assembly, light reflected from the target object is focused through the imaging lens assembly

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

light reflected from the target object is focused through the imaging lens assembly such that focused light is concentrated onto the sensor array

Methodology Applied
Scientific EffectLight focusing: Focusing

Implementation Method 3

The pixels of the sensor array are sequentially read out by image processing circuitry of the imaging system, generating an analog signal representative of a captured image frame

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP2507741B1Imaging-based scanner including border searching for image acquisition
Publication Date: 2015.01.21 SYMBOL TECH INC
  • EP2507741B1 patent drawingFigure 1
  • EP2507741B1 patent drawingFigure 2
  • EP2507741B1 patent drawingFigure 3

AI summary

A method utilizing an imaging-based bar code reader to identify a desired acquisition area within a captured image frame, the desired acquisition area including a target bar code and an extent of the desired acquisition area bounded by a border featuring: identifying a region of the captured image frame corresponding to an image of the target bar code; determining a reference point within the imaged target bar code; determining a reference point within an image of the desired acquisition area; searching for an image of the border of the desired acquisition area; identifying the imaged border of the desired acquisition area; and saving in memory a portion of the captured image frame corresponding to an image within the imaged border.