Sheet Detection Device Using Reflection and Transmission Imaging

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Solution Overview

Problem

Existing sheet detection systems face challenges in accurately recognizing the external shape and authenticity of sheets with transparent portions, as the transparent regions are often assimilated into the background, leading to incorrect edge detection and misrecognition, especially when using infrared light or single wavelength transmissive light, which fails to detect various types of documents with clear windows.

Innovation Solution

A sheet detection device comprising a first image collection unit for reflection image data and a second image collection unit for transmission image data, with a sheet detector that binarizes and performs OR processing on both to generate OR-processed image data, allowing for precise detection of the external shape and presence or absence of the sheet, even with transparent portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If transmission image data alone is used for detection, then the device structure can be simplified, but transparent portions are assimilated into the background causing incorrect edge detection

Engineering Contradiction:
Improvedetection device structureVSAvoidedge detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent combines transmission image data and reflection image data through OR processing to create composite image data. This merging allows the detection device to utilize both imaging modes simultaneously, where the transmission image reveals the overall sheet position while the reflection image captures transparent portions that appear dark against the background, thereby solving the edge detection accuracy problem without requiring overly complex separate detection systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a second imaging dimension (reflection imaging) to complement the primary transmission imaging dimension. By adding this alternative viewing mode and processing both through OR operations, the system overcomes the limitation of transparent portions being invisible in transmission mode, achieving accurate edge detection of transparent areas without significantly increasing device complexity.

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

2Measurement precision

If reflection image data alone is used for detection, then transparent portions can be detected as dark regions, but sheets with no transparent portions cannot be accurately detected

Engineering Contradiction:
Improvetransparent portion detection accuracyVSAvoidsheet detection reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent merges transmission image data and reflection image data using OR processing. For sheets with transparent portions, the reflection image provides the necessary contrast to detect edges. For sheets without transparent portions, the transmission image ensures reliable detection. The OR operation combines these complementary detection capabilities, ensuring high reliability across all sheet types.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the detection parameter by using different imaging modes (transmission and reflection) for different sheet types. By dynamically selecting and combining appropriate detection parameters based on sheet characteristics, the system achieves both high precision for transparent portions and high reliability for all sheet types.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If binarization and OR processing are applied to both image data, then detection precision is improved, but processing complexity increases

Engineering Contradiction:
Improvesheet detection precisionVSAvoidimage processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or hardware-based detection systems with a software-based image processing approach. By using binarization and OR processing algorithms, the system achieves high detection precision through computational methods rather than mechanical complexity, thereby improving precision while keeping the actual device structure relatively simple.

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

Solution Approach 2:

The patent applies parameter changes through image processing transformations (binarization and OR operations) on the collected image data. These parameter transformations convert grayscale image data into binary form and combine multiple data sets, achieving enhanced detection precision through algorithmic processing rather than hardware complexity.

Inventive Principle:
Principle #35Parameter changes

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 improves the precision of detecting the external shape and presence of sheets with transparent portions, reducing errors in sheet recognition and enabling accurate handling and processing of various types of documents, including banknotes with clear windows.

Implementation Method 1

a first image collection unit for reflection image data

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a second image collection unit for transmission image data

Methodology Applied
Scientific EffectLight transmission: Light

Data Source

PatentEP3598401B1Paper sheet detection device, paper sheet processing apparatus, and paper sheet detection method
Publication Date: 2022.01.12 GLORY LTD
  • EP3598401B1 patent drawingFigure 1
  • EP3598401B1 patent drawingFigure 2~3
  • EP3598401B1 patent drawingFigure 4(a)~4(b)

AI summary

The present invention provides a sheet detection device, a sheet handling device, and a sheet detection method capable of improving the precision of detecting at least one of the external shape or the presence or absence of a sheet having a transparent portion. The sheet detection device of the present invention includes a first image collection unit configured to collect reflection image data of a sheet under transport on a transport path, a second image collection unit configured to collect transmission image data of the sheet under transport on the transport path, and a sheet detector configured to detect at least one of the external shape or the presence or absence of the sheet based on the reflection image data and the transmission image data.