Virtual Endoscopy Artifact-Free Filet View Method
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing virtual endoscopy methods for elongated organs like intestines and blood vessels suffer from significant spatial deformations and display artifacts, making it difficult to accurately represent and analyze the internal structures.
Innovation Solution
The method involves determining an unfolding axis along the center of the lumen, adjusting the orientation of sampling planes to avoid intersections, and using a variable angular sampling increment to maintain constant arc length, ensuring accurate representation with minimal deformations and artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a perspective filet view method is used to image the interior of the intestine, then the visualization is achieved, but spatial deformations are introduced in an unpredictable way
Solution Approach 1:
The patent changes the sampling parameters from fixed angular increments to variable angular increments that adapt to the local geometry of the lumen. By calculating the mean curvature at each sampling point and adjusting the angular step size accordingly, the method maintains uniform sampling density along the centerline while avoiding spatial deformations in the unfolded view.
Solution Approach 2:
The patent introduces dynamic adjustment of sampling plane orientations based on the local geometry at each sampling point. The sampling planes are no longer fixed perpendicular to the centerline but are rotated to be perpendicular to the local mean curvature vector, allowing the system to adapt to changing luminal shapes and maintain accurate spatial representation.
2Manufacturing precision
If constant arc length sampling is used, then spatial deformations are reduced, but sampling planes may intersect inside the structure
Solution Approach 1:
The patent performs preliminary calculation of the mean curvature vector at each sampling point before determining the sampling plane orientation. This preliminary geometric analysis allows the method to predict and prevent potential intersections between sampling planes by adjusting orientations in advance, rather than correcting intersections after they occur.
Solution Approach 2:
The patent introduces the mean curvature vector as an intermediary element that mediates between the centerline geometry and the sampling plane orientations. This curvature vector serves as a bridge that translates the 3D luminal shape into appropriate sampling plane angles, ensuring that planes are oriented to avoid intersections while maintaining constant arc length sampling.
3Quantity of substance
If rays are cast from secondary sampling points, then sampling coverage is increased, but rays are not necessarily contained in a plane
Solution Approach 1:
The patent applies local quality by orienting sampling planes perpendicular to the local mean curvature vector at each sampling point rather than using a global fixed orientation. This local adaptation ensures that rays cast from secondary sampling points remain within their respective sampling planes, maintaining planarity while achieving comprehensive sampling coverage through the distributed network of locally-oriented planes.
Data Source
Figure 1~2
Figure 3~4
Figure 5(a)~5(c)
AI summary
The present invention concerns a method for performing virtual endoscopy on a volumetric image of a lumen-defining structure having an elongated lumen, comprising steps of determining an unfolding axis substantially inside the lumen, defining sampling planes substantially perpendicular to and intersecting said unfolding axis at sampling positions, selecting ray casting directions in said sampling planes, performing ray casting to define pixel values, and arranging said pixel values into an unfolded view, wherein said ray casting directions are selected so that the angle increment between them is substantially inversely proportional to the ray propagation distance into the lumen, from the unfolding axis to the structure. The present invention concerns also a computer program implementing the method.