Scattered Ray Correction in Energy Subtraction Imaging
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Solution Overview
Problem
Current radiation imaging systems using flat panel detectors face errors in bone and soft tissue thickness estimation due to varying scattered ray doses from different materials, leading to inaccurate material decomposition images in energy subtraction techniques.
Innovation Solution
An image processing apparatus that corrects for scattered rays by using pre-set transmittance information for multiple thicknesses of different materials, obtaining accurate thickness images by processing radiation images captured at various energies and accounting for both scattered and unscattered rays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If scattered ray correction is performed without considering material differences, then correction processing can be simplified, but errors in bone and soft tissue thickness estimation occur
Solution Approach 1:
The patent applies local quality by creating separate correction processing paths for different material types (bone and soft tissue). The processing unit determines material type for each pixel and applies material-specific transmittance information, allowing scattered ray correction to be tailored to local material characteristics rather than using a uniform correction approach.
Solution Approach 2:
The patent changes the parameter of transmittance information by preparing multiple sets of transmittance data corresponding to different material types and thickness combinations. The processing unit selects and applies the appropriate transmittance set based on the determined material type, thereby adapting the correction parameters to match the actual material being imaged.
2Measurement precision
If material-specific transmittance information is used for scattered ray correction, then thickness estimation accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple sets of transmittance information for different material types and thickness combinations before actual imaging processing. This preparation work is done in advance, so that during actual correction processing, the system only needs to select and apply the appropriate pre-computed data, reducing the computational burden during real-time operation.
Solution Approach 2:
The processing unit performs self-service by automatically determining the material type for each pixel and selecting the corresponding transmittance information without requiring manual intervention. The system autonomously manages the complexity of material-specific correction by implementing automated material identification and appropriate correction application.
3Productivity
If energy subtraction is performed with scattered rays included, then imaging process is simplified, but errors in bone and soft tissue images occur
Solution Approach 1:
The patent applies the taking out principle by separating scattered rays from the total radiation signal before performing energy subtraction. The processing unit calculates scattered ray components based on material type and thickness, then removes these scattered ray components from the original images, allowing energy subtraction to be performed on corrected images that are free from scattered ray contamination.
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 enables precise estimation of material thicknesses, reducing errors in bone and soft tissue imaging by effectively accounting for the scattered ray dose and material variations, thereby improving the accuracy of material decomposition images.
Implementation Method 1
obtain thickness images of the first and second materials in which the scattered rays have been corrected by using information regarding transmittance including scattered rays and transmittance not including the scattered rays that is set in advance for each of multiple thicknesses
Implementation Method 2
material decomposition images, such as a bone image and a soft tissue image for example, can be obtained by processing a plurality of images of different energies obtained by emitting X-rays with different tube voltages
Data Source
AI summary
An image processing apparatus includes a processing unit configured to, by using a plurality of pieces of information that correspond to a plurality of mutually different radiation energies and that have been obtained by irradiating an object with radiation and performing imaging, and information regarding transmittance including scattered rays and transmittance not including the scattered rays that is set in advance for each of multiple thicknesses of a first material and a second material that is different from the first material, obtain thickness images of the first and second materials in which the scattered rays have been corrected.