Tomographic Image Extrapolation and Smoothing for Artifact Reduction
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Solution Overview
Problem
Existing tomographic image generation methods require significant amounts of processed data and result in long waiting times before diagnostic processes can begin, while also introducing artifacts such as striped density irregularities.
Innovation Solution
A tomographic image generating apparatus and method that perform an extrapolating process along a prescribed direction and a smoothing process perpendicular to it, determining pixel values in non-detecting regions to reduce data requirements and prevent artifacts, using a radiation source and detector to capture projection image data while adjusting their relative positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional tomographic image generation methods are used to expand the represented range, then the field of view is expanded, but the amount of processed data increases and waiting time lengthens
Solution Approach 1:
The patent divides the field of view into a first field of view (fully sampled) and a second field of view (partially sampled). By segmenting the processing area, the system can process the first field of view with high quality while using simplified processing for the second field of view, reducing overall computation time and data requirements while still expanding the total represented range.
Solution Approach 2:
The patent applies partial sampling to the second field of view, acquiring only necessary projection image data rather than complete data for the entire expanded field of view. This partial action approach reduces the amount of data to be processed while still achieving the goal of expanding the represented range, thereby reducing waiting time.
2Area of stationary object
If conventional tomographic image generation methods are used to expand the represented range, then the field of view is expanded, but the amount of processed data increases
Solution Approach 1:
The patent segments the field of view into fully sampled and partially sampled regions. The partially sampled second field of view requires less processing data while still contributing to the expanded total field of view, thus reducing the overall quantity of processed data needed.
Solution Approach 2:
The patent extracts only the necessary projection image data for the second field of view that contributes to expanding the represented range, rather than processing complete data for the entire area. This extraction of essential data reduces the total amount of processed data while achieving field of view expansion.
3Loss of information
If extrapolating process is performed on acquired projection image data, then pixel values in non-detecting regions are determined, but striped density irregularities may occur
Solution Approach 1:
The patent performs a smoothing process on the acquired projection image data before performing the extrapolating process. This preliminary smoothing action prepares the data in advance to reduce high-frequency components that would otherwise cause striped density irregularities during extrapolation, thereby preventing artifacts while still determining pixel values in non-detecting regions.
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 the amount of processed data needed and minimizes artifacts, enabling faster generation of high-quality tomographic images with expanded regions without requiring special processing sequences.
Implementation Method 1
a radiation source for applying radiation to a subject, and a radiation detector for detecting radiation that has passed through the subject and acquiring projection image data from the detected radiation
Data Source
AI summary
A tomographic image of a subject is generated from projection image data acquired in a series of image capturing processes carried out by a radiation detector based on radiation emitted from a radiation source and transmitted through the subject. An extrapolating process is performed on each of the projection image data along a prescribed direction, and a smoothing process is performed on each of the projection image data along a direction perpendicular to the prescribed direction, thereby determining values of a plurality of pixels in non-detecting regions, which do not belong to a detecting region of the radiation detector. The determined values of the pixels also are used to generate the tomographic image.