Intermediate Image Generation Opacity Level Determination
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Solution Overview
Problem
Conventional methods for generating intermediate pseudo three-dimensional images from two-dimensional data using ray casting struggle to produce linear changes in opacity levels, resulting in nonlinear output pixel value changes, which hinders the creation of intermediate images that appear to change linearly with a changing phase.
Innovation Solution
The method determines opacity levels using a nonlinear function, specifically Formula (1): Fα(g) = 1.0 - t(α) ⋅ F A(g) + t(α) ⋅ F B(g), where t(α) is a monotonically increasing function defined by Formula (2), to allocate opacity levels based on pixel values, ensuring a smoother transition as the changing phase approaches either opacity level setting condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a linear interpolation method is used to determine opacity levels between two setting functions, then the changing phase transitions linearly, but the output pixel values change nonlinearly
Solution Approach 1:
The patent changes the parameter determination method from linear interpolation to nonlinear determination using minimum and maximum opacity levels. By calculating the minimum opacity level Fmin(g) and maximum opacity level Fmax(g) based on the two setting functions FA(g) and FB(g), and then determining the actual opacity level F(g) as a linear combination of these bounds, the patent achieves linear output pixel value changes while maintaining controlled changing phase transitions.
2Ease of operation
If the opacity level is determined by linearly interpolating between two setting functions, then the changing phase varies linearly, but the output image changes nonlinearly
Solution Approach 1:
The patent transforms the linear changing phase control into linear output image changes by introducing nonlinear parameter bounds Fmin(g) and Fmax(g). The opacity level F(g) is determined as Fa(g) + (Fb(g) - Fa(g)) × α, where Fa(g) and Fb(g) are the minimum and maximum opacity levels derived from the two setting functions. This parameter transformation ensures that linear variation in α produces linear changes in output pixel values.
3Device complexity
If conventional ray casting with linear opacity interpolation is used, then the intermediate image generation is computationally simple, but the visual transition appears nonlinear
Solution Approach 1:
The patent enhances the visual transition linearity by changing how opacity parameters are determined. Instead of directly interpolating between setting functions FA(g) and FB(g), the patent first computes bound functions Fmin(g) and Fmax(g) representing minimum and maximum opacity levels, then uses these bounds to determine the final opacity level. This parameter transformation maintains computational efficiency while achieving visually linear transitions.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
when generating an intermediate image, which is an image in the middle of changing from one to the other of two pseudo three-dimensional images generated by ray casting a three-dimensional image under two different opacity level setting conditions, determining an opacity level setting condition by determining an opacity level to be allocated according to each pixel value such that a variation in the opacity level for a change in a changing phase of the intermediate image become smaller as the changing phase approaches closer to a pseudo three-dimensional image generated under either one of the two different opacity level setting conditions in which a smaller value is allocated as the opacity level to be allocated according to each pixel value, and generating an intermediate image which appears to change substantially linearly with a linear change in the changing phase by ray casting the three-dimensional image under the determined opacity level setting condition.