In-line X-ray Dimensional Control Using Multi-angle Radiography
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Solution Overview
Problem
Existing X-ray dimensional control methods for manufactured objects are inefficient and costly, particularly when dealing with high-speed in-line control, as they require extensive data processing and expensive equipment, and often fail to accurately measure dimensions orthogonal to the direction of projection due to limited radiographic projections.
Innovation Solution
A method involving a series of manufactured objects with constant attenuation coefficients, using a transport device to move objects along a rectilinear trajectory, positioning X-ray generator tubes and sensors outside the conveying volume to acquire radiographic projections from different angles, and analyzing these images with a computer system to construct a digital geometric model for accurate linear dimension measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional CT or rotating gantry systems are used to achieve accurate three-dimensional measurements, then measurement precision is improved, but productivity deteriorates due to acquisition times of at least one minute per object plus loading and unloading times, limiting inspection to 10-30 objects per hour
Solution Approach 1:
The patent segments the measurement process by using multiple linear sensors positioned at different angles to simultaneously capture different projection views during a single pass through the conveyor, eliminating the need for sequential rotational scanning and enabling high-speed parallel data acquisition
Solution Approach 2:
The patent replaces the mechanical rotation system with a fixed array of linear sensors positioned at various angles, substituting mechanical movement with a stationary multi-sensor configuration that achieves the same measurement capability at much higher speeds
2Measurement precision
If vertical axis rotation or rotating gantry apparatuses are used to obtain highly accurate three-dimensional measurements through multiple projections, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses multiple linear sensors to capture multiple projection copies of the object simultaneously during a single conveyor pass, eliminating the need for complex rotational mechanisms while achieving complete three-dimensional reconstruction through computational methods
Solution Approach 2:
The patent creates a multi-functional measurement system where linear sensors positioned at different angles serve multiple purposes: each sensor captures projections for both three-dimensional reconstruction and direct two-dimensional dimensional measurements in its projection plane, eliminating the need for separate measurement systems
3Productivity
If limited radiographic projections are used in the direction of displacement, then productivity is improved by enabling high-speed conveyor operation, but measurement precision deteriorates for dimensions orthogonal to the projection direction
Solution Approach 1:
The patent adds angular dimension to the measurement system by positioning linear sensors at different angles relative to the conveyor direction, enabling three-dimensional reconstruction and accurate measurement of dimensions in all directions including those orthogonal to the displacement direction, despite limited projections along the displacement axis
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
Enables efficient and accurate measurement of linear dimensions in all directions, including those orthogonal to the projection direction, at high speeds and low costs, without the need for expensive equipment or extensive data processing, by constructing a complete three-dimensional digital model from limited radiographic projections.
Implementation Method 1
positioning at least one focus of an X-ray generator tube and image sensors each exposed and sensitive to X-rays obtained from an associated focus
Implementation Method 2
selecting a series of manufactured objects in which each of said objects is made of a material with a constant attenuation coefficient at all points of the object
Data Source
AI summary
A measurement method comprises acquiring, using image sensors (Cji) for each object during its displacement, at least three radiographic images of the region to be inspected. The images are obtained from at least three radiographic projections of the region to be inspected, the directions of projection (Dji) of which are different from each other. A computer system is provided with an a priori geometric model of the region to be inspected for the series of objects. Using the computer system and considering a constant attenuation coefficient and, from the a priori geometric model, at least three radiographic images of the region to be inspected, a digital geometric model of the region to be inspected is determined. For each object of the series, from the digital geometric model of the region to be inspected, at least one linear dimension measurement of the region to be inspected is determined.