Radiographic Signal Correction Using Light-Blocking Pixels

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Solution Overview

Problem

Existing radiographic imaging systems experience image unevenness due to variations in offset signal outputs among signal processing units, particularly caused by temperature distribution and gain differences in amplifier ICs, leading to image artifacts.

Innovation Solution

A radiographic imaging apparatus and method that corrects offset signals by using light-blocking pixels to generate offset signals, which are then subtracted from the effective pixel signals, employing quadratic or polynomial interpolation to align signals across different signal processing units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple signal processing units are used to process signals from different detection areas, then processing capacity is improved, but image unevenness occurs due to gain differences among amplifier ICs

Engineering Contradiction:
Improvesignal processing capacityVSAvoidimage uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the gain of each signal processing unit based on temperature detection. The control unit measures temperature variations among amplifier ICs and compensates for gain differences by adjusting amplification parameters, thereby maintaining image uniformity while utilizing multiple processing units for high-capacity signal processing.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If offset signal correction is performed using light-blocking optical black area, then shading artifact is reduced, but image unevenness remains due to temperature distribution effects

Engineering Contradiction:
Improveshading correction accuracyVSAvoidtemperature-induced image unevenness
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback control by continuously monitoring temperature variations among amplifier ICs and using this information to dynamically adjust gain settings. This closed-loop feedback mechanism compensates for temperature-induced offset signal variations, effectively eliminating image unevenness while maintaining the benefits of optical black area shading correction.

Inventive Principle:
Principle #23Feedback

3Productivity

If amplifier ICs are distributed across multiple detection areas, then signal processing efficiency is improved, but offset signal output varies among units due to temperature distribution

Engineering Contradiction:
Improvesignal processing efficiencyVSAvoidoffset signal consistency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent compensates for temperature-induced offset variations by dynamically adjusting amplification parameters of each amplifier IC based on real-time temperature measurements. This parameter adjustment ensures consistent offset signal output across all distributed signal processing units, maintaining reliability while preserving processing efficiency benefits.

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 suppresses image unevenness, resulting in high-quality radiographic images with reduced artifacts, even in the presence of temperature-induced signal variations.

Implementation Method 1

a conversion element, such as a photoelectric conversion element

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP3793189B1Radiography device and control method therefor
Publication Date: 2026.02.18 CANON KK
  • EP3793189B1 patent drawingFigure 1
  • EP3793189B1 patent drawingFigure 2
  • EP3793189B1 patent drawingFigure 3

AI summary

A radiographic imaging apparatus includes: an effective pixel area including a plurality of detection areas, in each of which a first pixel including a photoelectric conversion element and a second pixel including a light-blocking element are provided; a plurality of signal processing units that are provided so as to correspond to the plurality of detection areas and each process, for a corresponding one of the detection areas, an output signal from the first pixel and an output signal from the second pixel provided in the corresponding one of the detection areas; and a correction unit that makes, for each signal processing unit among the plurality of signal processing units, a correction to the output signal from the first pixel processed by the signal processing unit, by using the output signal from the second pixel processed by the signal processing unit.