Scanner Depth Correction via Backing Pattern Detection

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Solution Overview

Problem

Existing reading devices face challenges in accurately correcting for variations in reading depth due to factors like document flapping, which affects the accuracy of read values.

Innovation Solution

The implementation of a reading device that uses a detection pattern to detect variations in reading depth, allowing for correction of read data based on modulation transfer function (MTF) values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a predetermined pattern is formed on the backing of the object to be read to correct variations in read value, then the accuracy of read value correction is improved, but the detection accuracy depends on sheet thickness causing inconsistent correction across different thicknesses

Engineering Contradiction:
Improveread value accuracyVSAvoiddetection accuracy across different sheet thicknesses
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

A predetermined pattern is formed on the backing of the object to be read before the reading process. This pattern serves as a reference for detecting reading depth variations and correcting read values, enabling accurate correction even when the object changes position in the reading-depth direction during scanning

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The predetermined pattern on the backing acts as an intermediary element that mediates between the reading device and the object being read. By scanning this pattern and comparing it against reference data, the system can detect reading depth variations and apply appropriate corrections to the read values, making the detection independent of sheet thickness

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the object to be read changes position in the reading-depth direction at the scanning position due to flapping, then the ease of operation is improved (natural conveyance), but the measurement precision deteriorates due to variations in read value

Engineering Contradiction:
Improvenatural document conveyanceVSAvoidread value accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system scans a predetermined pattern on the backing and compares the scanned pattern against reference data to detect reading depth variations. This feedback mechanism enables real-time detection of position changes in the reading-depth direction, allowing the system to correct read values and maintain measurement precision even when documents flap during natural conveyance

Inventive Principle:
Principle #23Feedback

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 accurate detection and correction of reading depth variations, improving the accuracy and quality of scanned images regardless of document thickness.

Implementation Method 1

reads light reflected from a document surface in a visible area

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

reads light reflected from a document surface in an infrared area

Methodology Applied
Scientific EffectInfrared radiation detection: Infrared Radiation

Data Source

PatentEP3979612B1Reading device, image forming apparatus, and correction method
Publication Date: 2025.04.09 RICOH CO LTD
  • EP3979612B1 patent drawingFigure 1
  • EP3979612B1 patent drawingFigure 2~3
  • EP3979612B1 patent drawingFigure 4

AI summary

A reading device (1, 10, 25) and a method of correction. The reading device (1, 10, 25) includes a scanner (31) configured to read an image in a first wavelength range and an image in a second wavelength range from light reflected by a surface of a recording medium, a detector (32, 33) configured to detect a change from a reference position in a reading-depth direction when the surface (100a) of the recording medium is read by the scanner (31), based on an amount of characteristic read from the image in the second wavelength range, and a corrector (34) configured to correct the image in the first wavelength range based on the change detected by the detector (32, 33). The method includes reading the images in the first wavelength range and the second wavelength range from the light reflected by the surface (100a) of the recording medium.