Cone-Beam CT Artifact Correction via Material Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cone-beam computed tomography (CBCT) systems face challenges in accurately reconstructing images due to cone-beam artifacts, especially at larger cone angles, which interfere with diagnosis and require lengthy processing times for effective correction.
Innovation Solution
A method and apparatus that separate high-density and low-density material images from a CBCT image, iteratively subtracting a reproduced cone-beam artifact image to correct for artifacts, using a thresholding method and median filter to enhance accuracy and speed, allowing for quick removal of cone-beam artifacts even at larger cone angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an iterative approach is used to reduce cone-beam artifacts, then artifact reduction performance is improved, but processing time increases excessively
Solution Approach 1:
The patent applies preliminary action by performing material separation and scalar value calculation before the main artifact reduction process. The high-density material image is separated and its scalar value is computed in advance, allowing the iterative subtraction process to start with pre-prepared data, thus reducing overall processing time while maintaining artifact reduction effectiveness
Solution Approach 2:
The patent segments the image into high-density and low-density material components using thresholding. This segmentation allows different processing strategies to be applied to different material types, with the high-density material (which causes cone-beam artifacts) being separately identified and processed through scalar value subtraction, improving both speed and accuracy
2Productivity
If a two-pass algorithm is used to reduce computation time, then processing speed is improved, but correction performance is degraded at greater cone angles
Solution Approach 1:
The patent implements a dynamic iterative correction process that adapts to different cone angles. Instead of using a fixed two-pass algorithm, the system performs multiple iterations of scalar value subtraction, where the number of iterations can be adjusted based on the cone angle. For larger cone angles, more iterations are performed to maintain correction performance while still being faster than traditional methods
Solution Approach 2:
The patent changes key parameters including the threshold value for material separation and the scalar value used in subtraction. By dynamically adjusting these parameters based on the specific imaging conditions and cone angle, the system optimizes both processing speed and correction performance for different clinical scenarios
3Area of stationary object
If a large-area X-ray detector is used to image large volumes, then imaging coverage is improved, but cone-beam artifacts become more severe
Solution Approach 1:
The patent extracts and removes the harmful cone-beam artifact component from the reconstructed image. By separating the high-density material that causes artifacts and subtracting its scalar value contribution, the system effectively takes out the harmful factor while preserving the useful diagnostic information from the large-area detector imaging
Solution Approach 2:
The patent converts the harmful effect of high-density materials (which generate cone-beam artifacts) into a beneficial process. By identifying these materials through thresholding and using their scalar values for subtraction, the system transforms the artifact-source into a correction tool, where the same high-density materials that cause problems are used to guide the correction process
Data Source
AI summary
Disclosed is a technique for quickly removing and correcting a cone-beam artifact generated in a computed tomography (CT) image in consideration of bone and soft tissue regions when using a large-area X-ray detector in order to reduce a CT imaging time for large volumes in a cone-beam CT system. An apparatus includes an input unit configured to receive a start image including a cone-beam artifact, a computation unit configured to separate a high-density material image and a low-density material image from the start image received by the input unit, generate a reproduced image in which the cone-beam artifact is reproduced using the low-density material image, execute a correction process for subtracting the reproduced image from the start image to generate a corrected image, and iterate the correction process using the corrected image as a start image; and an output unit configured to output a final corrected image generated.