Field-Emission X-Ray Source for 3D Security Imaging
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Solution Overview
Problem
Conventional x-ray imaging systems face challenges in obtaining three-dimensional images of objects, particularly in security screening, due to the limitations of transmission-based two-dimensional x-ray systems and the time-consuming process of backscatter x-ray inspection, which struggles with fast-moving objects and has long warm-up times for x-ray sources.
Innovation Solution
The implementation of a field-emission x-ray source with individually-controllable pixels and a control system that allows for the generation of pulsed x-ray beams from multiple locations, enabling real-time three-dimensional imaging and rapid switching between different x-ray sources to improve image optimization and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If conventional transmission-based two-dimensional x-ray systems are used, then the imaging process is simple and fast, but three-dimensional information about the object is not obtained
Solution Approach 1:
The patent applies computed tomography (CT) imaging technology to transition from two-dimensional projection imaging to three-dimensional cross-sectional imaging. Multiple projection images are acquired from different viewing angles and reconstructed by a computer to form three-dimensional images, thereby obtaining comprehensive spatial information about the inspected object without significantly increasing system complexity
Solution Approach 2:
The patent introduces a computer as an intermediary to process and reconstruct multiple projection images into three-dimensional images. The computer acts as the mediating element that transforms raw projection data into meaningful three-dimensional visualizations, enabling the transition from 2D to 3D imaging while managing system complexity
2Measurement precision
If backscatter x-ray techniques with sequential pencil beam scanning are used, then material discrimination is improved, but the imaging process becomes time-consuming and cannot handle fast-moving objects
Solution Approach 1:
The patent segments the x-ray source into multiple independently controllable pixels arranged in a two-dimensional array. Each pixel can be individually controlled to emit x-rays, allowing parallel acquisition of multiple projection images simultaneously. This segmentation enables the system to maintain high material discrimination accuracy while dramatically increasing inspection throughput by eliminating sequential scanning
Solution Approach 2:
The patent implements continuous x-ray emission from all active pixels simultaneously, replacing the sequential pencil beam scanning approach. This continuous parallel action allows the system to acquire all necessary projection data in a single pass, thereby maintaining measurement precision while eliminating the time delays inherent in sequential scanning and enabling inspection of fast-moving objects
3Reliability
If filament-based x-ray tubes with long warm-up times are used, then stable x-ray flux is achieved, but the ability to image moving objects sharply and switch between beams is limited
Solution Approach 1:
The patent employs field emission cathodes that can be rapidly turned on and off without requiring long warm-up periods. These cathodes use cold field emission technology instead of heated filaments, allowing for extremely fast activation and deactivation. This enables the system to achieve stable x-ray flux when needed while maintaining the capability for rapid beam switching and imaging of moving objects, effectively replacing the slow, continuous operation of traditional filaments with controllable, on-demand emission
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 solution enables the generation of accurate, real-time three-dimensional x-ray images of objects, reducing operator training time, false alarms, and increasing efficiency in security screening, while allowing for precise imaging of moving objects and quick switching between different x-ray sources.
Implementation Method 1
a field-emission cathode comprising a plurality of individually-controllable pixels configured to emit electron beams
Implementation Method 2
When the electrons bombard the target, most of their energy is converted to thermal energy. A small portion of the energy is transformed into x-ray photons radiated from the target
Implementation Method 3
When the electrons bombard the target, most of their energy is converted to thermal energy
Implementation Method 4
An x-ray detector can be operable to detect the x-ray beams
Implementation Method 5
The pixels can be individually controlled such that the x-ray beams are generated simultaneously or in a predetermined sequence from different locations
Data Source
AI summary
Systems and methods for x-ray imaging and scanning of objects are disclosed. According to one aspect, the subject matter described herein can include providing an x-ray source configured to generate a plurality of individually-controllable x-ray beams, positioning an object to be imaged in a path for intercepting at least one of the x-ray beams, activating the x-ray source, detecting intensities of the emitted x-ray beams, and generating imaging data based on the intensities for constructing an image of the object.