Multiple-View-Angle Cargo Inspection Using Discrete Radiation Source Positions
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Solution Overview
Problem
Current CT scanning systems for cargo security inspection are inefficient due to slow scanning speeds and overlapping images of multiple objects, making it difficult to distinguish contrabands and requiring extensive data collection for precise reconstruction.
Innovation Solution
A multiple-view-angle cargo security inspection method involving a radiation source and data collecting unit that rotate or move in discrete positions around the cargo to acquire transmission projection data from multiple angles, allowing for faster scanning and precise three-dimensional image reconstruction using algorithms like filter back-projection, expectation maximization, or ordered subsets statistical algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If circular-orbit scanning manner is used, then mechanical structure is simple and easy to realize, but scanning speed is slow and efficiency is low for large bulk objects
Solution Approach 1:
The patent segments the scanning process into multiple discrete view angles (e.g., 0°, 45°, 90°, 135°) around the cargo, with the radiation source positioned at different angular positions. This segmentation allows parallel data acquisition from multiple angles, significantly improving scanning speed while maintaining mechanical simplicity through fixed positioning stations rather than continuous rotation mechanisms.
Solution Approach 2:
The patent transitions from a single-plane circular scanning approach to a multi-dimensional angular arrangement, positioning the radiation source at multiple discrete angles around the cargo in a three-dimensional space. This dimensional expansion enables simultaneous multi-angle imaging, dramatically increasing productivity without complicating the mechanical structure.
2Area of stationary object
If multiple articles are imaged in perspective imaging, then imaging coverage is comprehensive, but articles overlap in the image making it hard to distinguish them
Solution Approach 1:
The patent employs asymmetric angular positioning of the radiation source at multiple discrete view angles (e.g., 0°, 45°, 90°, 135°) around the cargo, creating non-overlapping projection paths. This asymmetric multi-angle arrangement ensures that articles at different positions and orientations are captured from diverse perspectives, preventing image overlap and enabling clear distinction of individual articles while maintaining comprehensive coverage.
Solution Approach 2:
The patent adds the angular dimension to the imaging process by capturing images from multiple discrete angles around the cargo. This transforms a single two-dimensional projection into a set of multi-angle two-dimensional images, effectively utilizing three-dimensional spatial information to resolve the overlap problem while maintaining comprehensive area coverage.
3Measurement precision
If a great number of projections are collected for precise reconstruction of large cross section objects, then reconstruction precision is improved, but inspection speed decreases and efficiency is low
Solution Approach 1:
The patent applies partial action by selecting a specific set of discrete view angles (e.g., 4-60 positions) that provides sufficient reconstruction precision without requiring complete 360-degree coverage. This selective sampling approach achieves acceptable reconstruction quality with fewer projections, thereby improving inspection speed and efficiency while maintaining adequate precision for security inspection purposes.
Solution Approach 2:
The patent changes the parameter of view angle distribution from continuous circular scanning to discrete angular positions. By optimizing the number and angular spacing of discrete viewing positions, the system achieves a balance between reconstruction precision and scanning speed, allowing faster inspection while maintaining sufficient image quality for detecting contrabands.
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 method significantly increases the efficiency of cargo security inspections by balancing scanning speed and precision, improving the accuracy of distinguishing objects and detecting contrabands, while allowing for flexible imaging modes including conventional and CT imaging.
Implementation Method 1
a radiation source for generating a beam of rays for transmitting through the object to be inspected
Data Source
AI summary
A multiple-view-angle cargo security inspection method for inspecting an object using a cargo security inspection system, the cargo security inspection system including a radiation source for generating a beam of rays for transmitting through the object to be inspected and a data collecting unit for collecting the transmission projection data after the beam of rays has transmitted through the inspected object, the method including a scanning step including: rotating the radiation source and/or the object about a rotation axis so as to achieve a relative rotation, thereby positioning the radiation source in a plurality of discrete positions with different view angles with respect to the inspected object, wherein, in each view angle, the radiation source moves along a straight line in a direction parallel to the rotation axis and at the same time scans the inspected object so as to acquire the transmission projection data at each view angle.