CT Projection Data Correction via Z-Effective Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Computed tomography (CT) images often suffer from artifacts due to radiation scatter and beam hardening, leading to inaccurate density and atomic composition representations of objects, which can result in false positives and negatives during inspections.
Innovation Solution
A method and system for correcting projection data in CT examinations by segmenting images to identify sub-objects, determining z-effective values, and performing beam hardening corrections using these values to generate corrected projection data, and iteratively updating CT values based on similarity comparisons between synthetic and measured projection data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If beam hardening correction is performed using conventional methods, then image artifacts are reduced, but measurement precision of atomic composition remains inaccurate
Solution Approach 1:
The patent changes the parameter used for beam hardening correction from conventional CT value-based methods to z-effective value-based methods. By determining z-effective values for sub-objects through segmentation and using these values to correct projection data, the system achieves more accurate representation of atomic composition while reducing image artifacts caused by beam hardening effects
Solution Approach 2:
The patent segments the imaged object into sub-objects to individually determine z-effective values for each sub-object. This segmentation approach allows for more precise beam hardening correction by accounting for the specific atomic composition of each sub-object, thereby improving measurement precision while reducing artifacts
2Measurement precision
If z-effective values are determined for sub-objects, then atomic composition representation is improved, but device complexity increases
Solution Approach 1:
The system segments the CT image into sub-objects and determines z-effective values for each sub-object. This segmentation enables precise atomic composition representation by characterizing each sub-object's material properties independently, improving measurement precision despite increased processing complexity
Solution Approach 2:
The patent introduces z-effective values as an intermediary parameter between conventional CT values and atomic composition representation. This intermediary enables more accurate atomic composition characterization while providing a systematic framework for handling the increased complexity through standardized calculation and application procedures
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 reduces image artifacts, improves the accuracy of density and atomic composition representations, enhancing the ability to discriminate between objects based on their true properties and reducing false positives and negatives.
Implementation Method 1
an image(s) is formed based upon the radiation absorbed and/or attenuated by interior aspects of the object
Implementation Method 2
objects having a higher density and/or atomic number may reflect or absorb a disproportionate amount of radiation in a low range(s) of the emitted radiation spectrum or spectra. This later phenomenon is sometimes referred to as beam hardening.
Implementation Method 3
the detector array may be configured to filter the impinging radiation photons (e.g., emitted across a single energy spectrum) based upon energy
Data Source
AI summary
Among other things, one or more techniques and/or systems are described for correcting projection data generated from a computed tomography (CT) examination of an object and/or for computing or updating a CT value of the object from the projection data. An image generator is configured to generate a CT image of an object under examination. Using this CT image, a set of actions are performed to correct projection data from which the CT image was generated and/or to update a CT value of one or more voxels within the CT image. In this way, the projection data and/or CT image is adjusted to reduce image artifacts and/or otherwise improve image quality and/or object detection.