Multiview Volumetric X-ray Imaging for Thin Object Detection

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Solution Overview

Problem

Conventional x-ray scanners are inadequate in detecting thin objects, as projection imaging methods fail to reliably identify objects with thin dimensions parallel to the radiation beams, leading to incomplete detection of contraband items.

Innovation Solution

The implementation of a multiview volumetric imaging system that uses multiple x-ray sources and detectors positioned to form projection images from different angles, allowing for the computation of volumetric images by measuring attenuation along multiple rays from various directions, thereby enhancing the detection of thin objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional projection imaging methods are used, then the system structure is simple and cost-effective, but thin objects with dimensions parallel to radiation beams cannot be reliably detected

Engineering Contradiction:
Improvedetection accuracy of thin objectsVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from conventional 2D projection imaging to 3D volumetric imaging by introducing multiple radiation sources positioned at different angles. This dimensional change enables detection of thin objects that were previously invisible in single-plane projections, as the多角度 views provide depth information necessary to distinguish thin objects from background structures.

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

Solution Approach 2:

The imaging system is segmented into multiple independent radiation sources, each positioned at a different angle relative to the object. This segmentation allows each source to capture specific angular information, and the combination of these segmented views reconstructs complete 3D volumetric data, improving detection capability while maintaining manageable system complexity.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple x-ray sources and detectors are positioned to form projection images from different angles, then volumetric images can be computed to detect thin objects, but the device complexity increases

Engineering Contradiction:
Improvevolumetric imaging accuracyVSAvoidnumber of sources and detectors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Each radiation source in the system is designed to be multi-functional, serving both as a projection source for its specific angle and as part of the overall volumetric reconstruction system. The detectors similarly serve multiple purposes by capturing data from multiple angular perspectives, reducing the need for additional specialized components and managing system complexity.

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

Solution Approach 2:

The patent merges multiple projection images from different angular sources into a single volumetric reconstruction. By combining the data from multiple sources and detectors through tomographic algorithms, the system achieves high measurement precision without requiring each individual component to be overly complex, as the complexity is distributed and integrated mathematically.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If conventional CT scanners are used to achieve volumetric imaging, then thin objects can be detected, but the cost and system complexity increase significantly

Engineering Contradiction:
Improvedetection of contraband itemsVSAvoidsystem configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system applies local quality by positioning radiation sources and detectors at specific strategic angles rather than using a complete 360-degree CT configuration. This localized approach captures sufficient angular information for volumetric reconstruction of contraband items while avoiding the excessive complexity and cost of full CT systems, optimizing the detection capability for security screening applications.

Inventive Principle:
Principle #3Local quality

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 improves the accuracy of detecting thin objects by forming detailed volumetric images, which can identify contraband items more effectively than traditional projection imaging systems, while maintaining efficiency and reducing the need for complex and costly CT scanners.

Implementation Method 1

The term 'x-rays' refers to electromagnetic radiation of a very short wavelength that is capable of penetrating many objects

Methodology Applied
Scientific EffectX-ray: X-Ray

Implementation Method 2

Because higher-density materials in the item being scanned will absorb more x-rays than lower-density materials, the signal output by the detectors that are in the 'shadow' of higher-density materials will be lower in value

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP1994400B1Radiation scanning systems and methods
Publication Date: 2021.04.07 LEIDOS SECURITY DETECTION & AUTOMATION INC
  • EP1994400B1 patent drawingFigure 1
  • EP1994400B1 patent drawingFigure 2
  • EP1994400B1 patent drawingFigure 3

AI summary

A method for operating an inspection system is disclosed in which an item under inspection may be moved in a first direction relative to and at least partially between at least one radiation source and at least some radiation detectors illuminated by the at least one radiation source. The radiation source and detectors may be operated such that ray paths extending linearly between the at least one radiation source and at least some of the radiation detectors form acute angles with respect to a plane having a normal direction coinciding with the first direction that are substantially in excess of three degrees. Data accumulated by the radiation detectors may be processed to form a three-dimensional tomographic data image of at least a portion of the item under inspection. In some embodiments, transmission data based upon outputs of a plurality of radiation detectors may be processed to form a tomographic image, in which, for all possible orientations of a three dimensional plane, the orientation vectors of at least some of the rays of radiation for which transmission data was accumulated and used to form the tomographic image form an angle of less than eighty-five degrees or greater than ninety five degrees with respect to the plane.