Dynamic X-ray Flux Control for Security Scanner Image Quality
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Solution Overview
Problem
Computed Tomography (CT) baggage scanners face inefficiencies due to constant x-ray flux emission, leading to indistinguishable images from dense objects and unnecessary radiation exposure, which reduces image quality and shortens the lifespan of the x-ray tube.
Innovation Solution
A security examination apparatus with an x-ray source and detectors configured to adjust x-ray flux based on real-time detection data, dynamically adjusting radiation output as the object moves through the scanner, optimizing radiation usage and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the x-ray tube emits x-rays at a fixed rate, then the system operation is simple and reliable, but the image quality deteriorates when scanning dense objects and the x-ray tube lifespan is reduced
Solution Approach 1:
The x-ray tube flux is changed from fixed to dynamically adjustable based on real-time detection. The system continuously monitors the density of objects in the scanning path and adjusts the x-ray flux accordingly, allowing the system to adapt to varying object densities while maintaining operational reliability.
Solution Approach 2:
A feedback loop is established where detectors monitor object density in real-time and provide signals to the control system, which then adjusts the x-ray tube flux. This closed-loop control ensures that the x-ray flux is optimized for each specific scanning scenario, improving image quality without compromising system reliability.
2Ease of operation
If the x-ray tube emits x-rays at a fixed rate, then the system operation is simple, but unnecessary radiation exposure occurs when no objects are being scanned
Solution Approach 1:
The system uses detectors to continuously monitor whether objects are present in the scanning path. When no objects are detected, the feedback signal triggers the x-ray tube to reduce or stop emission, eliminating unnecessary radiation exposure while maintaining simple automated operation.
Solution Approach 2:
The system automatically detects the presence or absence of objects and self-adjusts the x-ray flux without requiring manual intervention. This self-service capability eliminates wasteful radiation exposure while keeping the system easy to operate.
3Duration of action of stationary object
If the x-ray tube emits x-rays at a fixed rate, then continuous operation is maintained, but the lifespan of the x-ray tube is reduced
Solution Approach 1:
Instead of continuous fixed-rate emission, the x-ray tube operates periodically based on detected need. The system emits x-rays only when objects are present and requires emission, reducing overall operational stress on the tube while maintaining continuous scanning capability.
Solution Approach 2:
The x-ray flux parameter is dynamically changed based on scanning conditions. By adjusting the flux intensity and duration according to object density and presence, the system reduces cumulative stress on the x-ray tube, extending its lifespan while maintaining continuous operation capability.
4Productivity
If a dense bag is scanned with fixed x-ray flux, then the scanning process is straightforward, but the contents are rendered indistinguishable in the image
Solution Approach 1:
The x-ray flux is dynamically adjusted based on the detected density of the bag. When a dense bag is detected, the system increases the x-ray flux to ensure sufficient penetration and maintain image distinguishability, while keeping the scanning process efficient and automated.
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
Enhances image quality by adjusting radiation flux according to object density, reducing unnecessary radiation exposure, and extending the lifespan of the x-ray source by optimizing energy use.
Implementation Method 1
a first detector configured to detect x-rays that have traversed the object in the upstream portion
Implementation Method 2
a second x-ray detector configured to detect second x-rays emitted from the x-ray source that have traversed the object in the downstream portion
Implementation Method 3
Highly dense objects absorb more radiation than less dense objects, and thus an object having a high density, such as a metal gun, for example, will be apparent when surrounded by less dense objects
Data Source
AI summary
Radiation flux can be adjusted “on the fly” as an object (204) is being scanned in a security examination apparatus. Adjustments are made to the radiation flux based upon radiation incident on a first radiation detector (226) in an upstream portion (233) of an examination region. The object under examination is thus exposed to different radiation flux in coordination with a downstream motion (235) of the object relative to a second radiation detector (228). The radiation flux is adjusted so that a sufficient number of x-rays (that traverse the object) are incident on the second radiation detector. Images of the object can then be generated based upon data from the second radiation detector, where these images are thus of a desired/higher quality.