Dual-Energy Radiation Detector Pixel Equalization

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Solution Overview

Problem

Dual-energy radiation detection devices face challenges in achieving accurate foreign substance inspection, particularly with substances like cartilage, which have high radiotransparency, leading to small contrast differences in radiation images, making it difficult to perform subtraction processing when radiation detectors have different pixel counts.

Innovation Solution

The radiation detection device is designed with vertically-piled radiation detectors that overlap in the radiation incident direction, allowing for temporal alignment without detection timing control, and employs image processing sections that apply pixel change processing, such as interpolation and thinning-out, to equalize the number of pixels from both detectors, facilitating arithmetic processing like subtraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the pixel area in the low energy radiation detector is reduced to increase contrast difference for high radiotransparency substances, then the contrast difference in radiation images is improved, but the number of pixels becomes different from the high energy radiation detector, making subtraction processing difficult

Engineering Contradiction:
Improvecontrast differenceVSAvoidpixel number matching
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by adjusting the pixel area in the low energy radiation detector to optimize contrast difference for detecting high radiotransparency substances like cartilage. The pixel area is specifically designed to be smaller than in the high energy detector, and this parameter is compensated through image processing techniques that resize images to match pixel counts before subtraction processing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an image processing section as an intermediary that performs pixel number matching between images from detectors with different pixel configurations. This intermediary component enables subtraction processing by transforming images to a common pixel grid, resolving the incompatibility caused by different pixel areas while preserving the optimized contrast enhancement.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If vertically-piled radiation detectors are used to simplify temporal alignment, then detection timing control is simplified, but the pixel areas must be different to optimize low energy detection, creating pixel number mismatch

Engineering Contradiction:
Improvedetection timing alignmentVSAvoidpixel number consistency
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transitions from a side-by-side detector arrangement to a vertically-piled configuration, changing the spatial dimension of detector placement. This dimensional change simplifies temporal alignment since both detectors simultaneously capture radiation from the same specimen position. The pixel area difference is then managed through image processing that operates in the data dimension rather than requiring physical pixel uniformity.

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

Solution Approach 2:

The patent segments the detection system into two functionally specialized detectors with different pixel areas optimized for their respective energy ranges. The low energy detector uses smaller pixels for enhanced contrast, while the high energy detector uses larger pixels. This segmentation is reconciled through image processing that integrates the segmented data streams into a unified analysis framework.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If side by side radiation detectors with different pixel areas are used to detect different foreign substance sizes, then detection versatility is improved, but temporal alignment and subtraction processing become complex

Engineering Contradiction:
Improveforeign substance size detectionVSAvoidsynchronization control
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the detection capabilities of two detectors with different pixel areas into a unified dual-energy detection system. Rather than operating independently for different size detections, both detectors work simultaneously on the same specimen, with their data combined through image processing. This merging maintains versatility while simplifying control through the vertically-piled configuration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The vertically-piled detector configuration provides universal functionality for detecting both small and large foreign substances by capturing radiation at two energy levels simultaneously. The system achieves multi-functionality through energy discrimination rather than spatial separation, allowing a single detection position to serve multiple detection purposes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration enables easy arithmetic processing, including subtraction, even when the number of pixels in the radiation detectors differs, improving the accuracy of foreign substance inspection by enhancing contrast differences in radiation images.

Implementation Method 1

a first radiation detector (32) that detects radiation in a first energy range transmitted through a specimen (S) of interest and generates first radiation image data (L) representing a first radiation image

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

a second radiation detector (42) that detects radiation in a second energy range transmitted through the specimen (S) and generates second radiation image data (H) representing a second radiation image

Methodology Applied
Scientific EffectCompton scattering: Compton Scattering

Implementation Method 3

a radiation detector having a scintillator layer and pixels

Methodology Applied
Scientific EffectScintillation: Scintillation

Data Source

PatentEP2479557B1Radiation detecting device
Publication Date: 2017.07.26 HAMAMATSU PHOTONICS KK
  • EP2479557B1 patent drawingFigure 1
  • EP2479557B1 patent drawingFigure 2
  • EP2479557B1 patent drawingFigure 3

AI summary

A radiation detection device 80 according to an embodiment is a radiation detection device for a foreign substance inspection using a subtraction method, and includes a first radiation detector 32 that detects radiation in a first energy range transmitted through a specimen S and generates a first image, a second radiation detector 42 that detects radiation in a second energy range higher than the radiation in the first energy range and generates a second image, a first image processing section 34 that applies image processing to the first image, and a second image processing section 44 that applies image processing to the second image, wherein a first pixel width in an image detection direction of each pixel of the first radiation detector 32 is smaller than a second pixel width in the image detection direction of each pixel of the second radiation detector 42, and the first image processing section 34 and the second image processing section 44 carry out pixel change processing to make the number of pixels of the first image and the number of pixels of the second image equal to each other.