Optical Absorption Coefficient Calculation for Non-Orthogonal CT Planes
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Solution Overview
Problem
Existing methods for calculating optical absorption coefficients in CT imaging, such as the convolution integral method and techniques in Patent Literatures 1 and 2, are inefficient when the tomographic plane is not orthogonal to the optical axis, leading to unnecessary calculations and reduced speed enhancement.
Innovation Solution
An optical absorption coefficient calculation device and program that utilize global and rotational transform operators to transform specific object coordinates into a global coordinate system, enabling direct convolution operations and reducing unnecessary calculations by focusing on necessary parts of the object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the convolution integral method or existing speed-enhancement techniques are used, then calculation speed is improved for orthogonal tomographic planes, but the method cannot support non-orthogonal tomographic planes requiring full object calculation
Solution Approach 1:
The patent divides the object into multiple local coordinate systems, each corresponding to a specific tomographic plane orientation. By segmenting the calculation domain according to different orientations, the system can apply optimized convolution operations tailored to each segment rather than performing full-object calculations for all orientations.
Solution Approach 2:
The patent transforms coordinates between different reference frames using transform operators that adapt to the specific orientation parameters of each tomographic plane. By changing the coordinate system parameters to match the plane orientation, the system maintains calculation efficiency across different orientations without requiring full recalibration.
2Productivity
If transform operators are used to enable direct convolution for specific regions, then calculation speed improves, but device complexity increases
Solution Approach 1:
The patent pre-calculates and stores transform operators for different tomographic plane orientations before actual imaging. By performing the coordinate transformation setup in advance, the system avoids complex real-time calculations during image acquisition, thereby improving productivity without proportionally increasing operational complexity.
Solution Approach 2:
The patent introduces transform operators as intermediary mathematical tools that bridge between the detector coordinate system and various object-oriented coordinate systems. These operators act as mediators that simplify the relationship between different coordinate frames, making the overall system more manageable despite the multiple transformations required.
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
Enables high-speed calculation of optical absorption coefficients for specific regions of an object by directly performing convolution operations, reducing errors due to axis deviations and improving image quality.
Implementation Method 1
transmission projection data acquired on a detection plane of a detector for light beams applied from a light source to an object
Implementation Method 2
detector for light beams applied from a light source to an object
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Provided is an optical absorption coefficient calculation technique capable of calculating an optical absorption coefficient of any part of an object at high speed. An optical absorption coefficient calculation device A includes a global coordinate transform operator determination unit 3 that determines a global coordinate transform operator for transforming a specific coordinate in a specific region into a global coordinate value, a rotational transform operator determination unit 4 that determines a rotational transform operator for transforming the global coordinate value into a coordinate after relative rotation, a detector coordinate value determination unit 5 that determines a detector coordinate value based on a coordinate acquired by applying the global coordinate transform operator and the rotational transform operator to the specific coordinate, a convolution operation unit 6 that performs convolution operation with a filter function on transmission projection data, and an integration unit 7 that calculates the optical absorption coefficient of the specific coordinate by acquiring a calculated value of the convolution operation calculated based on the transmission projection data of the detector coordinate value for each rotation angle and accumulating the calculated value.