Sparse X-ray Detector Array with Iterative Reconstruction

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Solution Overview

Problem

Conventional X-ray imaging systems, particularly those using projection imaging, struggle to reliably detect and characterize thin objects, especially when they are packaged with other objects, due to the lack of distinct pixel groups in projection images, leading to incomplete or inaccurate object characterization.

Innovation Solution

The use of a sparse detector array in conjunction with iterative reconstruction methods, such as the Algebraic Reconstruction Technique (ART), to form volumetric images from multiple radiation measurements from different angles, allowing for the detection of thin objects by compensating for the reduced number of detectors with advanced image processing techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a full detector array is used, then measurement precision and image quality are improved, but device complexity and cost increase

Engineering Contradiction:
Improveimage qualityVSAvoiddetector array size
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies partial action by using a sparse detector array that captures only a subset of the measurements that would be obtained with a full detector array. Instead of measuring all possible projection angles and positions, the system selectively measures only those projections needed to reconstruct the volumetric image, thereby reducing detector requirements while maintaining adequate image quality through iterative reconstruction algorithms

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent replaces the mechanical/physical solution of using a large number of detectors with a computational solution. Iterative reconstruction algorithms process the limited measurements from the sparse detector array to reconstruct volumetric images, substituting computational complexity for physical detector complexity and achieving comparable image quality with fewer detectors

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If projection imaging is used, then system simplicity is maintained, but detection reliability of thin objects deteriorates

Engineering Contradiction:
Improveimaging system simplicityVSAvoidthin object detection
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent transitions from two-dimensional projection imaging to three-dimensional volumetric imaging. By acquiring measurements from multiple angles and reconstructing volumetric data, the system enables detection of thin objects that would be indistinguishable in 2D projection images, as the volumetric representation preserves depth information and allows visualization of objects along the beam path

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

3Reliability

If multiple measurements from different angles are taken, then thin object detection reliability is improved, but measurement time and productivity decrease

Engineering Contradiction:
Improvethin object detectionVSAvoidimaging speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies partial action by measuring only the necessary projections from multiple angles rather than acquiring complete data sets at all possible angles. The sparse detector array combined with iterative reconstruction allows the system to obtain sufficient angular information for reliable thin object detection while minimizing the number of measurements required, thereby balancing detection reliability with imaging speed

Inventive Principle:
Principle #16Partial or excessive 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

This approach enables the cost-effective production of accurate volumetric images, reducing the number of detectors required and maintaining image quality, while also reducing the overall cost and size of the imaging system, effectively addressing the limitations of conventional systems in detecting thin objects.

Implementation Method 1

X-ray imaging typically includes passing high-energy radiation (i.e., X-rays) through an object to be imaged. X-rays from a source passing through the object interact with the internal structures of the object and are altered according to various characteristics of the material (e.g., transmission, scattering and diffraction characteristics, etc.). By measuring changes (e.g., attenuation) in the X-ray radiation that exits the object, information related to material through which the radiation passed may be obtained

Methodology Applied
Scientific EffectX-ray attenuation: Absorption (EM radiation)

Data Source

PatentEP2817661B1X-ray imager with sparse detector array
Publication Date: 2019.10.02 L3 COMMUNICATIONS SECURITY AND DETECTION SYSTEMS INC
  • EP2817661B1 patent drawingFigure 1
  • EP2817661B1 patent drawingFigure 2
  • EP2817661B1 patent drawingFigure 3

AI summary

A system and method for imaging objects with a sparse detector array that includes fewer detectors than conventional x-ray scanning systems. The sparse detector array is positioned to receive x-ray radiation from the at least one x-ray source after passing through an inspection area. The sparse detector array includes a plurality of rows of detector elements, wherein at least some of the plurality of rows are separated by gaps such that the at least some of the plurality of rows are non-contiguous. An iterative reconstruction process is used to determine a volumetric image of the object from the radiation measurements recorded by the detectors in the sparse detector array.