Dual-Energy Radiation Detector Pixel Mismatch Subtraction

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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 and making it difficult to distinguish them from meat, and the difference in pixel numbers between low-energy and high-energy detectors complicates subtraction processing.

Innovation Solution

The radiation detection device is designed with vertically-piled radiation detectors that overlap in the radiation incident direction, allowing for synchronized detection timings and image correction to ensure the same position accuracy, even when the number of pixels differs between detectors, thereby preventing pseudo edges and enhancing subtraction image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the pixel width in the orthogonal direction is reduced to increase the number of pixels for better contrast difference in low-energy range detection, then the contrast difference in radiation images between substances with high radiotransparency is improved, but the number of pixels in the low-energy detector becomes different from the high-energy detector, making subtraction processing difficult

Engineering Contradiction:
Improvecontrast difference in radiation imageVSAvoidpixel number mismatch between detectors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by adjusting the pixel width in the orthogonal direction for the low-energy detector to have a different value than the high-energy detector. This allows each detector to be optimized for its specific energy range, with the low-energy detector having smaller pixel widths to enhance contrast difference for substances like cartilage, while the high-energy detector maintains larger pixel widths suitable for its detection characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the detection system into two independent detectors with different pixel configurations - the low-energy detector with smaller pixels for high-contrast detection and the high-energy detector with larger pixels for overall imaging. This segmentation allows each detector to be independently optimized without compromising the other, and the image correction unit processes each detector's output separately before combining them.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If two radiation detectors with different pixel areas are arranged side by side to detect different energy ranges, then dual-energy detection capability is achieved, but the number of pixels differs between detectors, complicating arithmetic processing and image alignment

Engineering Contradiction:
Improvedual-energy detection capabilityVSAvoidarithmetic processing and image alignment
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent transitions from a side-by-side arrangement to a vertically-piled arrangement where detectors overlap in the radiation incident direction. This dimensional change allows both detectors to capture the same specimen area simultaneously, and the image correction unit processes the images to ensure proper alignment before arithmetic operations, thereby maintaining ease of operation while preserving dual-energy detection capability.

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

Solution Approach 2:

The patent introduces an image correction unit as an intermediary between the two detectors with different pixel configurations. This intermediary unit processes the images from both detectors, adjusting and aligning them so that arithmetic processing can be performed accurately despite the different original pixel areas, thus facilitating easy operation while maintaining versatility.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If the pixel width in the conveying direction is reduced to increase the number of line outputs for better spatial resolution, then the spatial resolution is improved, but the number of line outputs becomes different between detectors, making synchronized detection and subtraction processing difficult

Engineering Contradiction:
Improvespatial resolutionVSAvoidnumber of line outputs
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by allowing the pixel width in the conveying direction to vary between detectors - the low-energy detector has smaller pixel widths for higher spatial resolution in that direction, while the high-energy detector has larger pixel widths. The image correction unit dynamically adjusts the line outputs to match between detectors, enabling synchronized detection and arithmetic processing despite the different initial configurations.

Inventive Principle:
Principle #15Dynamics

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, such as subtraction, even with detectors having different pixel numbers, resulting in improved accuracy and prevention of pseudo edges in the subtraction image, thus facilitating effective foreign substance inspection.

Implementation Method 1

a radiation detector having a scintillator layer and pixels, and detects radiation transmitted through a specimen and generates a radiation image

Methodology Applied
Scientific EffectScintillation: Scintillation

Data Source

PatentEP2479558B1Radiation detecting device
Publication Date: 2017.10.04 HAMAMATSU PHOTONICS KK
  • EP2479558B1 patent drawingFigure 1
  • EP2479558B1 patent drawingFigure 2
  • EP2479558B1 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, including a first radiation detector 32 and a second radiation detector 42 that detect radiation transmitted through a specimen S, a timing control section 50 that controls detection timings, and an image correction section 34, wherein a first pixel width Wb1 in an orthogonal direction orthogonal to an image detection direction of each pixel of the first radiation detector 32 is smaller than a second pixel width Wb2 in the orthogonal direction of each pixel of the second radiation detector 42, the timing control section 50 synchronizes detection timings of the second radiation detector 42 to detection timings of the first radiation detector 32, and the image correction section 34 sums Wb2/Wb1 pixel data successive in an image from the first radiation detector 32.