Opacity Curve Adjustment for Virtual Endoscopy Viewpoint Changes
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Solution Overview
Problem
Conventional virtual endoscopic image generation methods struggle to maintain clear visualization of the interior of lumens, especially in structures like bronchial tubes and blood vessels, due to varying pixel values along the luminal structure, leading to incomplete display of inner walls when the viewpoint position changes.
Innovation Solution
A projection image generation apparatus and method that adjusts the opacity curve based on the viewpoint position change by determining a movement amount using data distribution histograms, allowing the opacity curve to be translated and updated accordingly to maintain optimal opacity settings for clear visualization across different viewpoints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed opacity curve is used for volume rendering, then the initial virtual endoscopic image can be generated, but the inner walls of lumens become invisible when the viewpoint position changes
Solution Approach 1:
The patent applies dynamics by making the opacity curve adjustable and adaptable to different viewpoint positions. Instead of using a fixed opacity curve, the system dynamically modifies the opacity curve based on the current viewpoint position within the lumen, allowing the virtual endoscopic image to maintain reliable visualization of inner walls regardless of viewpoint changes.
Solution Approach 2:
The patent implements parameter changes by modifying the opacity curve parameters according to the viewpoint position. The system calculates an appropriate opacity curve for each viewpoint position by adjusting parameters such as the threshold value that determines which voxles are rendered as transparent or opaque, ensuring consistent visualization of inner walls across different viewpoints.
2Ease of operation
If manual opacity and chromaticity settings are used, then user control is achieved, but the process is time-consuming and subjective
Solution Approach 1:
The patent applies self-service by enabling the system to automatically determine and adjust the opacity curve based on the viewpoint position and local data characteristics. The computer automatically analyzes the three-dimensional data around the current viewpoint and selects appropriate opacity parameters without requiring manual user intervention, thus saving time while maintaining effective control.
Solution Approach 2:
The system uses feedback by continuously monitoring the viewpoint position and automatically adjusting the opacity curve parameters accordingly. The computer analyzes the local data distribution at each viewpoint position and modifies the opacity settings in real-time, creating a closed-loop system that adapts to changing conditions without manual input.
3Device complexity
If a single opacity curve is used for all viewpoint positions, then processing simplicity is maintained, but visualization quality deteriorates in tapered structures
Solution Approach 1:
The patent implements local quality by applying different opacity curve characteristics to different viewpoint positions within the lumen. Instead of using a uniform opacity curve for all positions, the system adjusts the opacity parameters locally according to the specific geometric characteristics of the lumen at each viewpoint, such as tapering or branching, thereby improving visualization accuracy without excessive complexity.
Solution Approach 2:
The system uses dynamics to transition from a static, single opacity curve to a dynamic, position-dependent opacity curve. The opacity parameters are automatically adjusted based on the current viewpoint position and local data characteristics, allowing the visualization quality to adapt to the specific geometry of tapered structures like bronchial tubes while maintaining reasonable processing complexity.
Data Source
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AI summary
In generating a virtual endoscopic image, an interior of a lumen is made viewable even when the viewpoint position is changed. A virtual endoscopic image generation means (12) generates a virtual endoscopic image by volume rendering based on three-dimensional data. An opacity curve setting means (13) sets an opacity curve which defines the relationship between pixel values of the three-dimensional data and opacity values. A viewpoint position setting means (14) sets a viewpoint position of a virtual endoscopic image. A movement amount determination means (15) determines a movement amount of the opacity curve with respect to an opacity curve at a reference viewpoint position. When a virtual endoscopic image is generated by the virtual endoscopic image generation means (12), the opacity curve setting means (13) sets an opacity curve obtained by moving the opacity curve by the determined movement amount in the virtual endoscopic image generation means (12).