Tomographic Imaging Device with Contour-Based Sparse Sampling
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Solution Overview
Problem
Sparse angular sampling in tomographic imaging techniques leads to varying sampling densities, resulting in over-sampling of regions closer to the z-axis and under-sampling of regions farther away, causing artifacts and contradicting the goal of reduced radiation dose.
Innovation Solution
A tomographic imaging device with a radiation detector on a curved track around an axis, where sampling positions are determined based on the estimated object contour to maintain constant sampling density, with straight paths between sampling positions having approximately equal lengths, and a planning unit to control the radiation source for optimal data acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant angular distance between sampling positions is used, then device complexity is reduced and acquisition time is shortened, but sampling density varies within the object causing over-sampling in inner regions and under-sampling in outer regions
Solution Approach 1:
The patent applies local quality by adjusting the angular distance between sampling positions based on the local radial distance from the z-axis. Outer regions with larger radial distances receive smaller angular distances between samples, while inner regions receive larger angular distances. This localized adjustment ensures uniform sampling density across the entire object while maintaining reduced total sample count and acquisition time.
2Device complexity
If constant angular distance between sampling positions is used, then the sampling procedure is simplified, but this leads to over-sampling of inner object regions and under-sampling of outer object regions
Solution Approach 1:
The planning unit implements local quality by determining angular distances between sampling positions based on the radial distance of object regions from the z-axis. Each region receives a locally optimized angular distance that compensates for the geometric sampling density variation, ensuring uniform coverage without requiring complex manual configuration.
Solution Approach 2:
The patent applies preliminary action by using a planning unit to pre-calculate optimal sampling positions and angular distances before the actual tomographic scan. This preliminary determination of non-uniform angular spacing based on object geometry eliminates the need for complex real-time adjustments during scanning while achieving uniform sampling density.
3Object-affected harmful factors
If fewer sampling positions are used to reduce radiation dose, then radiation exposure is reduced, but sampling density becomes insufficient in outer object regions leading to artifacts
Solution Approach 1:
The patent applies local quality by allocating sampling positions non-uniformly based on radial distance from the z-axis. Outer regions with larger radial distances receive proportionally more sampling positions with smaller angular distances between them, ensuring sufficient sampling density in these previously under-sampled regions while maintaining an overall reduced total number of samples compared to uniform sampling.
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 ensures consistent sampling density across the object, reducing artifacts and radiation exposure by optimizing sampling positions based on the object's contour, thereby enhancing image quality and reducing radiation dose.
Implementation Method 1
a radiation detector for measuring radiation traveling through an object to be imaged, the radiation detector being configured to measure radiation travelling along at least one ray path only at a plurality of selected sampling positions on a curved track around an axis
Data Source
AI summary
The invention relates to tomographic imaging device (1). The device (1) comprises a radiation detector (3) for measuring radiation traveling through an object to be imaged, the radiation detector (3) being configured to measure radiation only at a plurality of selected sampling positions on a curved track around an axis (z). A planning unit (12) is configured to determine the selected sampling positions on the basis of an estimated contour (44; 53) of the object (21) in a plane (x-y) substantially perpendicular to the axis (z). Further, the invention relates to a method for operating the device (1). The invention is particularly applicable in computed tomography imaging.