JP-7854586-B2 - Program for extracting the centerline of a 3D image

Inventors

• 米山 繁
• 福澤 大輔
• 栗原 好昭

Assignees

• 株式会社アイブイラボ

Dates

Publication Date

20260507

Application Date

20221214

Claims (5)

1. A centerline extraction device for extracting and drawing a centerline from three-dimensional image data of an object by computational processing, equipped with means for performing the following processes by computer. (a) A three-dimensional image representing the contour shape of the object is obtained, and the entire three-dimensional image is assumed to be filled without gaps with voxels corresponding to pixels. (b) Heat sources are set up inside all of the above voxels, or at regularly distributed grid points, that continuously emit a constant amount of heat per unit time. (c) The heat from the above heat source may be released in all directions from the center of the voxel. (d) The voxels on the outermost surface of the object and the adjacent external voxels are heat-absorbing sources that are at zero degrees and absorb heat to the greatest extent possible. (e) Calculate the temperature of all voxels when a steady state is reached in which heat exchange occurs between voxels with heat sources and voxels with heat absorption sources, and between voxels with heat sources and other voxels with heat sources, and a constant temperature difference is maintained between each voxel. (f) Read the temperature difference described above and leave the group of voxels that are hotter than the surroundings. (g) Connect the remaining voxel groups that are hotter than the surrounding area in order to draw the center line.
2. The centerline extraction apparatus according to claim 1, characterized by repeatedly removing voxels in order from those with lower temperatures to those with higher temperatures, thereby leaving a group of voxels with higher temperatures than the surrounding area.
3. The centerline extraction apparatus according to claim 1 or 2, characterized in that it calculates the temperature of all voxels using the thermal diffusion equation when a steady state is reached while a constant temperature difference is maintained between each voxel.
4. A computer program for centerline extraction that causes a computer to function as the means described in claim 1.
5. A computer-readable recording medium containing the computer program described in claim 4.

Description

This invention relates to a centerline extraction program for extracting and drawing centerlines from three-dimensional image data of an object through computational processing. For example, continuous pores formed within porous ceramic materials, or blood vessels inside the human body as seen in MRI scans, are winding and have uneven thickness and cross-sectional shapes. To analyze the state of such objects, their centerlines are extracted and plotted. Various computational processing techniques have been introduced for extracting the center line from three-dimensional image data obtained by photographing an object, using computer computation (Patent Documents 1-4) (Non-Patent Documents 1-3). Japanese Patent Publication No. 2002-269539Patent No. 4675509Patent No. 4688361Patent No. 4748843 Sequential Algorithms and Properties of Thinning and Thinning of Three-Dimensional Digital Images Using Euclidean Distance Transformation, IEICE Transactions on Electronics, Information and Communication Engineers, Vol. J79-D-II No.10, pp.1675-1685, October 1996.Topological analysis of three-dimensional network structures using wire thinning, Journal of Polymer Science, Vol. 58, No. 1, pp. 13-21 (Jan., 2001)"A Three-Dimensional Steady-State Heat Conduction Analysis Program Using Finite Element Method," by Kengo Nakajima, published by the Information Technology Center, University of Tokyo. Figure 1 is an explanatory diagram illustrating the relationship between the object and the voxel group.Figure 2 is an explanatory diagram of voxels and heat sources.Figure 3 is an explanatory diagram of voxels on the outer surface of an object and adjacent external voxels.Figure 4(a) is an explanatory diagram illustrating an example of centerline extraction for an object with little change in outer diameter. Figure 4(b) is an explanatory diagram illustrating an example of centerline extraction for an object with a rapidly changing outer diameter according to the present invention. Figure 4(c) is an explanatory diagram illustrating an example of centerline extraction for an object using a known method. Figure 4(d) is an explanatory diagram illustrating an example of centerline extraction for a branched portion of an object according to the present invention.Figure 5 is an illustrative diagram illustrating an example of the calculation formula used for centerline extraction in the present invention.Figure 6 shows a case where the external shape changes rapidly, with (a) being an example of calculation using a known method and (b) being an explanatory diagram of an example of calculation according to the present invention.Figure 7 shows a case where there is a bulge in the middle of a blood vessel, with (a) being an example of calculation according to the present invention and (b) being an explanatory diagram of an example of calculation using a known method.Figure 8 is an explanatory diagram of the calculation model using the finite volume method.Figure 9 is an explanatory diagram of the calculation procedure using the finite volume method (1).Figure 10 is an explanatory diagram of the calculation procedure using the finite volume method (2).Figure 11 is an explanatory diagram of the calculation procedure using the finite volume method (3).Figure 12 is an explanatory diagram illustrating the temperature comparison of extracted grid points. The embodiments of the present invention will be described in detail below, for each example.