X-ray Detection Arrays Remove Luminance Lines

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Solution Overview

Problem

In X-ray inspection apparatuses using direct conversion-type X-ray detection element arrays, sensitivity is reduced at the connecting portions between arrays, leading to luminance reduction lines in images, which are difficult to correct, especially when inspecting thick objects like meat.

Innovation Solution

The apparatus employs a conveyance unit, X-ray radiation unit, and image processing unit that includes edge detection and horizontal gradation processing to synthesize X-ray transmission images, effectively removing luminance reduction lines by combining direct and indirect conversion-type X-ray detection arrays to handle both soft and hard X-rays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple direct conversion-type X-ray detection element arrays are disposed side-by-side to increase detection area, then the detection coverage is improved, but sensitivity is reduced at the connecting portions between arrays causing luminance reduction lines in images

Engineering Contradiction:
Improvedetection areaVSAvoidsensitivity
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The detection system is divided into multiple direct conversion-type X-ray detection element arrays arranged side-by-side, where each array independently detects X-rays in its designated region. This segmentation enables coverage of a larger detection area while maintaining the high sensitivity characteristics of direct conversion technology in each segment, resolving the contradiction between detection area and sensitivity at connecting portions.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If linear correction processing is applied to cancel luminance reduction lines, then image uniformity is improved for thin objects, but correction effectiveness is insufficient for thick objects with non-linear X-ray absorption characteristics

Engineering Contradiction:
Improveimage uniformityVSAvoidcorrection effectiveness
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The correction method transitions from linear correction processing to gradient-based correction processing that adapts to the actual X-ray absorption characteristics of the object. By calculating luminance gradients in the conveyance direction and using them to correct luminance reduction lines, the system achieves effective correction for both thin and thick objects with varying absorption properties, resolving the limitation of linear correction for non-linear absorption cases.

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 allows for accurate detection of foreign matters even in thick objects by enhancing image quality and removing sensitivity-related artifacts, improving the detection of materials like glass, rubber, and light metals.

Implementation Method 1

a plurality of direct conversion-type X-ray detection element arrays disposed side-by-side in rows along a direction intersecting both a conveyance direction in which the object is conveyed by the conveyance unit and a radiation direction in which X-rays are radiated by an X-ray radiation unit and configured to convert X-rays of a first energy band into electric charge

Methodology Applied
Scientific EffectDirect conversion: Photoelectric Effect

Implementation Method 2

an edge detection unit configured to carry out edge detection processing on the X-ray transmission image to generate an edge detected image

Methodology Applied
Scientific EffectEdge detection:

Implementation Method 3

a horizontal direction gradation unit configured to carry out horizontal direction gradation processing along the conveyance direction on the edge detected image to generate a horizontal direction gradation image

Methodology Applied
Scientific EffectHorizontal direction gradation:

Data Source

PatentEP3361240B1X-ray examination device
Publication Date: 2020.07.15 ISHIDA CO LTD
  • EP3361240B1 patent drawingFigure 1
  • EP3361240B1 patent drawingFigure 2(a)~2(b)
  • EP3361240B1 patent drawingFigure 3

AI summary

An X-ray inspection apparatus includes a conveyance unit, an X-ray radiation unit, an X-ray detection unit, and an image processing unit. The X-ray detection unit has a plurality of direct conversion-type X-ray detection element arrays disposed side-by-side in rows along a direction intersecting both a conveyance direction in which an object is conveyed by the conveyance unit and a radiation direction in which X-rays are radiated by the X-ray radiation unit. The image processing unit has an edge detection unit configured to carry out edge detection processing on an X-ray transmission image to generate an edge detected image, a horizontal direction gradation unit configured to carry out horizontal direction gradation processing on the edge detected image to generate a horizontal direction gradation image, and a synthesizing unit configured to synthesize the X-ray transmission image and the horizontal direction gradation image to generate a post-processing X-ray transmission image.