Voxel
The voxel (British: voxel) is the element of the volume and expresses the value of the regular lattice unit in the three-dimensional space. A term "voxel" is the bag word which put "volume" (volume) and "pixel (pixel)" together. This is analogy of two-dimensional image data being expressed in a pixel. The voxel is used for visualization and the analysis of medical care and scientific data well. The volume type display may express resolution in voxel. For example, it is expression such as 512*512*512 voxel.
Like a pixel, voxel in itself does not have a coordinate in the space, but can guess by position relations (each position in the data structure, i.e., to constitute one solid image) with the other voxel group.
Table of contents
Voxel data
The voxel is a cube of the small volume with constant scalar value / vector value and has a scalar value / vector level corresponding to the lattice / pixel when I expressed three-dimensional data discretely. The border of the voxel fits an adjacent lattice between lattices exactly. The resolution of voxel data is limited, and only the central data of each cell are correct. Under the supposition that voxel data sampled a signal set a limit to a band appropriately, it is necessary to apply a low-path filter to the correct reconstruction of the data point between the sampled voxel. When I make it suitable for the approximation of this low-path filter visually, there is the thing which applied multinomial expression interpolation to the three dimensions.
The voxel level expresses various attributes. By the CT scanning, X-ray absorption factor (Hounsfield Unit) is a price of the voxel [1]. The values to be provided by MRI and a supersonic wave are different each.
The voxel may support plural scalar values, and it becomes the vector value. For example, in the echographic B mode and Doppler echo, density or a speed rate of change are provided, and those data support each voxel position.
Directly three-dimensional rendering includes the available value. For example, it is a normal vector and the color for the surface.
Voxel has some different kinds. One is means to express a three-dimensional object in three-dimensional BitMap not a vector (on the contrary, the polygon expresses it in a vector). It is the voxel topography used by a game and simulation well one more. Generally, the voxel topography is used as substitute means of the height map. Unlike a height map, I can express an overhang and a cave or a bridge by the three-dimensional topography.
Use
Data visualization
I can visualize the solid comprised of voxel by direct volume rendering and I extract the surface from there as a polygon and can do rendering. The marching cube method is used for a surface sampling method well, but other technique exists, too.
TV game
- As for the game of NovaLogic company including "Delta Force", there are many things adopting a voxel-based rendering technology.
- There are several things using the voxel in the game of Westwood Studios. "Command & コンカーレッドアラート" was "the command & コンカータイベリアン sun" and performed rendering of a vehicle in voxel. I performed rendering of people in voxel by the game of "Blade Runner".
- I used voxel in game "A+M+O+K" for Sega Saturn.
- There is the voxel mode pack which a fan produced in "Duke Nukem 3D" and converts indication into voxel.
- "CRYSIS" uses the voxel for topography system.
- Voxelstein 3D draws the object which I can destroy in voxel [2].
Expansion
One of the things which generalized voxel has "doc cell (doxel)" or dynamic voxel. This is used by the four-dimensional data such as three-dimensional animation data. For example, this can say a three-dimensional image of 100*100*100 voxel if there is the image of 100*100*100*100 doc cell even if 100 tops form a line. A resource is necessary for storage and the operation of such data in large quantities, but helps space-time studies.
Allied item
Footnote, source
- ^ Novelline, Robert. Squire's Fundamentals of Radiology. Harvard University Press. 5th edition. 1997. It is p.29 ISBN 0674833392
- ^ Voxelstein 3D
Outside link
This article is taken from the Japanese Wikipedia Voxel
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