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Publication Number
US-12442779-B2
Publication Date
2025-10-14
Expiration Date
Abstract
An inspection portal includes a first x-ray source configured to emit a first beam, a first backscatter detector configured to detect backscatter from the first beam, a second x-ray source configured to emit a second beam, a second backscatter detector configured to detect backscatter from the second beam, and at least one first collimator and at least one second collimator, each oriented to detect backscatter from the associated beam and to block scatter from the other beam. The first and second backscatter detectors are configured to weight signals acquired using each of their detector element based on the first and second beams. The first backscatter detector is configured to use signal processing techniques to mitigate crosstalk due to scatter from the second beam, and the second backscatter detector is configured to use the signal processing techniques to mitigate crosstalk due to scatter from the first beam.
Core Innovation
The described inspection portal images an object using multiple x-ray sources and corresponding backscatter detectors. The portal includes a first x-ray source emitting a first beam and a first backscatter detector detecting backscatter from the first beam, and a second x-ray source emitting a second beam and a second backscatter detector detecting backscatter from the second beam. First and second collimators are coupled to the respective backscatter detectors and are oriented to detect backscatter from their associated beam while blocking scatter from the other beam.
This cross-beam scatter blocking is combined with signal processing techniques at each backscatter detector to mitigate crosstalk due to scatter radiation from the other beam. In the described embodiments, the backscatter detectors include a multi-element detector array, and the portal performs signal weighting based on current beam position so that signals acquired by detector elements are weighted according to the current position of the beams.
Additional embodiments discuss combining backscatter imaging with transmission radiography, where a transmission beam is generated using a single x-ray source with a shutter and a fan beam collimator, and a backscatter beam is generated using a chopper wheel, with timing so transmission and backscatter are incident on the object at different times or using selective detector inactivity to reduce interference. The document further describes energy discrimination for backscatter detection, including use of energy thresholds and plastic scintillators loaded with high-Z materials such as bismuth or tin, with optional high-energy-resolution detectors, and dynamic collimation concepts to further improve image quality and reduce interference.
Claims Coverage
The independent claims cover two-beam backscatter imaging with cross-beam scatter blocking and detector-based crosstalk mitigation, an additional transmission-and-backscatter imaging configuration using collimation to prevent backscatter from reaching the backscatter detector, and multi-element backscatter detectors with position-dependent signal weighting combined with signal processing crosstalk mitigation.
Cross-beam collimation and mutual backscatter crosstalk mitigation
An inspection portal comprising a first x-ray source emitting a first beam towards the object, a first backscatter detector detecting backscatter from the first beam, a second x-ray source emitting a second beam towards the object, a second backscatter detector detecting backscatter from the second beam, at least one first collimator coupled to the first backscatter detector and at least one second collimator coupled to the second backscatter detector, where the first collimator is oriented to detect backscatter from the first beam and to block scatter from the second beam and the second collimator is oriented to detect backscatter from the second beam and to block scatter from the first beam, and where each backscatter detector uses signal processing techniques to mitigate crosstalk due to scatter radiation from the other beam.
Transmission-and-backscatter simultaneous incidence with backscatter-detector isolation
An inspection portal comprising a first x-ray source emitting a first beam, a collimator defining an aperture generating a transmission beam from the first beam, a transmission detector detecting transmission from the transmission beam, a second x-ray source emitting a second beam, a chopper wheel generating a backscatter beam from the second beam such that the transmission beam and the backscatter beam are incident on the object simultaneously, a backscatter detector detecting backscatter from the backscatter beam, and at least one collimator coupled to the backscatter detector positioned and oriented to prevent backscatter from the transmission beam from reaching the backscatter detector.
Position-dependent detector-element weighting with dual-beam signal-processing crosstalk mitigation
An inspection portal comprising a first x-ray source emitting a first beam towards the object, a first backscatter detector detecting backscatter from the first beam, a second x-ray source emitting a second beam towards the object, a second backscatter detector detecting backscatter from the second beam, at least one first collimator coupled to the first backscatter detector and at least one second collimator coupled to the second backscatter detector oriented to block cross-beam scatter, where the first and second backscatter detectors each comprise a plurality of detector elements, where the first and second backscatter detectors weight signals acquired using each detector element based on a current position of the first and second beams, and where each backscatter detector uses signal processing techniques to mitigate crosstalk due to scatter from the other beam.
Across the independent claims, the coverage centers on oriented collimators that block cross-beam scatter and on mitigating crosstalk using signal processing at backscatter detectors. One independent claim further requires multi-element backscatter detectors that apply position-dependent signal weighting based on current beam position, and another independent claim covers a transmission radiography configuration using a chopper wheel for backscatter with collimation that prevents transmission-beam backscatter from reaching the backscatter detector.
Stated Advantages
Reduce interference by blocking cross-beam scatter and mitigating crosstalk using signal processing techniques.
Improve image quality by further reducing interference using energy discrimination and dynamic collimation concepts.
Reduce interference in combined imaging by controlling timing so transmission and backscatter are incident at different times or by selectively deactivating detection when crosstalk is higher.
Documented Applications
Imaging an object in an inspection portal, including vehicle inspection x-ray portals.
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