3D Image Reconstruction Artifact Reduction via Segmentation
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Solution Overview
Problem
Current methods for reconstructing three-dimensional image data sets from two-dimensional projection images, particularly in X-ray imaging and tomosynthesis, suffer from significant artifacts due to highly absorbent regions like metal parts or calcifications, which are not effectively addressed by existing artifact reduction techniques, especially when only a limited number of projection images with restricted angular ranges are used.
Innovation Solution
A method involving morphological operations to segment highly absorbent regions, generating processing images, creating mask images, and using synthetic images to reduce artifacts by selectively backprojecting filtered images, allowing for efficient artifact reduction with minimal computing requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If filtered backprojection is used for image reconstruction, then reconstruction speed is improved, but image artifacts occur due to highly absorbent regions
Solution Approach 1:
The patent segments the projection images by detecting highly absorbent regions (metal parts or calcifications) and separating them from the surrounding tissue. This segmentation allows the reconstruction algorithm to treat different regions differently, applying artifact reduction techniques specifically to areas affected by highly absorbent materials while maintaining reconstruction speed through efficient region-based processing.
Solution Approach 2:
The patent applies different processing strategies to different regions of the image. Highly absorbent regions are processed with artifact reduction algorithms that account for their specific properties, while other regions use standard reconstruction methods. This local quality approach ensures optimal artifact reduction in problem areas without compromising overall reconstruction efficiency.
2Object-generated harmful factors
If iterative reconstruction approach is used instead of filtered backprojection, then image artifacts are reduced, but computing requirements increase
Solution Approach 1:
The patent applies iterative artifact reduction techniques selectively only to regions containing highly absorbent materials rather than performing full iterative reconstruction on the entire image. This partial action approach maintains the speed advantages of filtered backprojection while reducing artifacts in critical areas, avoiding the excessive computing requirements of complete iterative reconstruction.
Solution Approach 2:
By segmenting the image into highly absorbent regions and non-highly absorbent regions, the patent applies computationally intensive artifact reduction only where necessary. This segmentation strategy reduces the overall computing burden compared to full iterative reconstruction while still achieving significant artifact reduction in the problematic regions.
3Loss of time
If limited number of projection images with restricted angular range are used, then scanning time is reduced, but image artifacts are enhanced
Solution Approach 1:
The patent changes the processing parameters and algorithms used for reconstruction when dealing with limited angular ranges. By detecting the restricted angular coverage and applying specialized artifact reduction techniques tailored to this condition, the system maintains image quality and reduces artifacts even when scanning time is reduced and fewer projection images are available.
Solution Approach 2:
The patent applies enhanced artifact reduction processing specifically to regions where artifacts are most likely to occur due to limited angular coverage. This localized quality enhancement addresses the artifact problem in critical areas without requiring additional scanning time or projection images.
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 effectively reduces or eliminates artifacts from highly absorbent regions with minimal computational effort, improving image quality by deciding voxel reconstruction data sources based on mask values, thus enhancing the accuracy of three-dimensional image data sets in applications like 3D mammography.
Implementation Method 1
highly absorbent objects are located in the imaging area. In particular, metal parts or calcifications, in other words deposits of calcium salts, exhibit an X-ray absorption differing significantly from tissue
Data Source
AI summary
A method for determining a three-dimensional image data set from a plurality of two-dimensional projection images of an object under examination applies at least one morphological operation to each projection image in order to provide a processing image associated with the respective projection image. At least one respective imaging segment is segmented, in which a highly absorbent region is mapped, depending on the associated processing image, and a respective mask image is generated in which pixels belonging to the imaging segment are marked. An associated synthetic image for each projection image is determined, the image data of which within the imaging segment is set to predetermined values. The projection images and the synthetic images are separately filtered. The three-dimensional image data set is determined by backprojecting the mask images to determine a mask value for each voxel of the image data set.