Iterative CT Image Reconstruction at High Pitch

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Solution Overview

Problem

Existing imaging systems using penetrating radiation face challenges in achieving complete pi-line coverage when objects are transported at high speeds, leading to insufficient measurement data for accurate volumetric reconstruction.

Innovation Solution

The system employs a transport mechanism that adjusts the speed of object traversal relative to the X-ray source and detector geometry, allowing for incomplete pi-line coverage, and utilizes iterative reconstruction techniques to derive volumetric data from measurement data collected during high-speed scanning, enabling efficient image reconstruction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the object is transported at high speed through the scan path, then the scanning efficiency and productivity are improved, but the measurement data becomes insufficient for complete pi-line coverage, degrading the manufacturing precision of the reconstructed image

Engineering Contradiction:
Improvescanning speedVSAvoidimage reconstruction accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system performs preliminary actions by collecting measurement data at high speed with intentionally incomplete pi-line coverage, then applies iterative reconstruction algorithms that incorporate prior knowledge and constraints to complete the image reconstruction process, achieving both high scanning speed and acceptable image quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the parameter of pi-line coverage from the traditional requirement of complete coverage to incomplete coverage acceptable at high pitches, enabling faster scanning while using advanced reconstruction algorithms to maintain sufficient image quality for security screening applications

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If the transport speed is increased to improve productivity, then the scanning time is reduced, but the measurement data quality deteriorates due to insufficient pi-line coverage

Engineering Contradiction:
Improvescanning timeVSAvoidmeasurement data completeness
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The system performs partial action by collecting only the necessary measurement data at high speed without achieving complete pi-line coverage, relying on iterative reconstruction algorithms to fill in the gaps and produce sufficient image quality for security screening

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The invention replaces the mechanical requirement of complete pi-line coverage through controlled object movement with a computational approach using iterative reconstruction algorithms that can generate accurate images from incomplete measurement data

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

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 faster scanning of objects while maintaining acceptable image quality, even at high speeds, and adapts to different security screening needs by operating in multiple modes with varying speeds and geometries.

Implementation Method 1

an X-ray source to emit a conical beam of X-ray radiation

Methodology Applied
Scientific EffectX-ray radiation: X-Ray

Implementation Method 2

measuring the intensity of X-rays received through the object. The attenuation of the X-ray beam depends on material properties of the object

Methodology Applied
Scientific EffectAttenuation: Absorption (EM radiation)

Data Source

PatentEP3365871B1Systems and methods for image reconstruction at high computed tomography pitch
Publication Date: 2023.06.28 LEIDOS SECURITY DETECTION & AUTOMATION INC
  • EP3365871B1 patent drawingFigure 1
  • EP3365871B1 patent drawingFigure 2
  • EP3365871B1 patent drawingFigure 3A

AI summary

Methodologies, systems, apparatus, and non-transitory computer-readable media are described herein to facilitate acquisition of volumetric data and volumetric image reconstruction. An imaging system can be configured to transport an object at a speed relative to the scan path of an X-ray source such that insufficient measurement data is collected for classically complete geometrical coverage. Iterative image reconstruction techniques may be used to generate volumetric images based on measured volumetric data of at least a portion of the object.