Offset CT Scanning Reduces Beam Hardening Artifacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current CT scanning technologies face challenges in achieving high-quality scans of complex objects like turbine blades due to beam hardening and concave wall effects, particularly when dealing with objects that have varying thickness and complex cross-sections, leading to reduced image quality and increased artifacts.
Innovation Solution
The method involves positioning the object offset from the axis of rotation in a CT scanning apparatus, allowing the object to be scanned at multiple angles, and optionally using a jacket with a filling material to maintain consistent material thickness and reduce scattering, thereby improving image quality and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the object is positioned centrally on the axis of rotation, then the scanning path length is minimized, but beam hardening and concave wall effects increase leading to image artifacts
Solution Approach 1:
The patent applies asymmetry by deliberately offsetting the object from the central axis of rotation. This asymmetric positioning creates an annular scan path where the object rotates around a region rather than through the center, which distributes the x-ray beam path lengths more evenly and reduces the concentration of scattered rays that cause concave wall effects and beam hardening artifacts.
Solution Approach 2:
The patent introduces a radial dimension offset to the traditional central scanning approach. By positioning the object at a radial distance from the axis of rotation, the scanning path is transformed from a central rotational path to an annular path, effectively adding a spatial dimension consideration that reduces beam path variations and minimizes harmful scattering effects.
2Strength
If the x-ray voltage is increased to penetrate thicker objects, then the penetration capability improves, but the contrast between materials decreases
Solution Approach 1:
The patent applies local quality by using different x-ray voltage settings for different regions of the object. The system performs a preliminary scan to identify regions of varying thickness, then applies higher voltage specifically to thicker regions that require enhanced penetration, while maintaining lower voltage in thinner regions to preserve material contrast. This localized adjustment optimizes both penetration and contrast in different parts of the object.
3Productivity
If multiple objects are scanned simultaneously, then the productivity increases, but the complexity of optimizing scan parameters for all features increases
Solution Approach 1:
The patent applies universality by developing a standardized offset positioning methodology that can be applied to multiple different object types and configurations. The annular scanning approach with offset positioning serves as a universal solution that works for various object geometries, allowing multiple objects to be scanned simultaneously with consistent parameter optimization strategies rather than requiring unique parameter sets for each object.
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 approach results in reduced beam artifacts, higher contrast, and improved scanning efficiency, enabling better image quality and reduced scan time for complex objects, even when scanning multiple objects simultaneously.
Implementation Method 1
An x-ray source produces polychromatic x-rays that penetrate a part and form an x-ray image on a detector
Implementation Method 2
The composition of the part may effectively attenuate the CT scanning x-ray beam
Implementation Method 3
The support is rotatable relative to the emitting and receiving elements about an axis of rotation to allow creation of an image from projections each taken at a different relative angle of rotation
Implementation Method 4
Aiming to reduce beam hardening and poor penetration, the known arrangements teach to increase the voltage of the x-ray emitting apparatus
Implementation Method 5
use a physical or software-based scatter correction
Implementation Method 6
The x-ray images are combined via a process called reconstruction to produce a 3D representation of the object
Data Source
AI summary
There is provided a method for scanning of an object in a scanning apparatus. The method comprises disposing the object on a support of the scanning apparatus, so that the object is positioned between an imaging beam emitting element and an imaging beam receiving element oppositely disposed to either side of the support. The support is rotatable relative to the emitting and receiving elements about an axis of rotation to allow creation of an image from projections each taken at a different relative angle of rotation. The object is positioned on the support so that a part to be scanned of the object is offset from the axis of rotation. The method further comprises operating the scanning apparatus at the multiple relative angles of rotation to produce an image of the offset object.