X-ray Deficiency Pixel Correction with Noise Evaluation

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Solution Overview

Problem

X-ray deficiency pixels in X-ray images, caused by automatic detection and reset operations in flat panel detectors, lead to noise amplification and unnatural image patterns when corrected by amplifying output values based on deficiency ratios, affecting diagnostic accuracy.

Innovation Solution

A radiation imaging apparatus with acquisition, correction, calculation, and noise reduction means to evaluate and reduce noise levels in X-ray deficiency pixels by referencing adjacent non-deficiency pixels, using correction coefficients calculated through regression analysis and noise reduction filtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If output values are amplified based on deficiency ratio to correct X-ray deficiency pixels, then correction accuracy is improved, but noise level increases

Engineering Contradiction:
Improvecorrection accuracyVSAvoidnoise level
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the correction approach by introducing an evaluation parameter (evaluation value) that assesses the noise level increase caused by correction. Based on this evaluation, the system dynamically adjusts the correction strength or applies noise reduction processing, transforming the fixed amplification approach into a adaptive parameter-based correction system that balances accuracy and noise control

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback by calculating an evaluation value that measures the noise level increase resulting from correction operations. This evaluation feedback is then used to control the correction process, allowing the system to adjust correction intensity or apply additional noise reduction when the evaluation indicates excessive noise amplification, thereby resolving the contradiction between correction accuracy and noise control

Inventive Principle:
Principle #23Feedback

2Device complexity

If automatic X-ray detection is implemented to start accumulation operation, then interface complexity is reduced, but charge removal occurs during detection period

Engineering Contradiction:
Improveinterface complexityVSAvoidcharge loss
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The patent converts the harmful effect of charge removal during the detection period into a beneficial correction opportunity. By detecting which pixels suffered charge removal (X-ray deficiency pixels) and applying targeted correction using adjacent non-deficiency pixels, the system transforms the previously lost information into correctable data, maintaining image quality while preserving the simplified automatic detection approach

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent performs preliminary identification of X-ray deficiency pixels during the detection phase by comparing charges between adjacent pixels. This preliminary action allows the system to flag and subsequently correct affected pixels in the accumulation phase, preventing permanent information loss while maintaining the benefit of automatic detection without complex interfaces

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

Suppresses noise level deterioration during pixel correction, resulting in more accurate and natural X-ray images by aligning noise levels with adjacent pixels, enhancing diagnostic image quality.

Implementation Method 1

a flat panel detector (to be referred to as an FPD hereinafter) has been put into practical use, which accumulates X-rays as a charge signal, converts it into a digital signal

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3061398B1Radiographic imaging device and method for controlling same, radiographic image processing device and method, and program and computer-readable storage medium
Publication Date: 2020.09.23 CANON KK
  • EP3061398B1 patent drawingFigure 1
  • EP3061398B1 patent drawingFigure 2
  • EP3061398B1 patent drawingFigure 3

AI summary

A radiation imaging apparatus acquires a radiation image from radiation detected by radiation detection means, corrects a first pixel that is a correction target in the radiation image by referring to a second pixel other than the first pixel, calculates an evaluation value that evaluates an increase in a noise level caused by correcting the first pixel, and performs processing of reducing the noise level for the first pixel after the correction based on the calculated evaluation value.