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Uses Voxel processing is used to visualize 3D shapes and structures using a number of cross-sectional images.
In medicine, brains, hearts, tissue sections, and even whole human bodies are sampled via several volumetric sampling techniques, including MRI, CT, PET, confocal microscopy and volumetric ultrasound.
So how does it work? A set of cross-sectional digital images (slices), called a dataset, is created with a number of pixels on each. The distance between any two consecutive pixels in each slice represents a real world distance. This is called the interpixel distance.
The distance between any two consecutive slices also represents a real world depth, called the interslice distance.To process a volumetric dataset, the slices are stacked in the computer's memory according to the interpixel and interslice distances. This builds up a 'virtual' co-ordinated space which accurately reflects the real world dimensions of the originally sampled object.
Additional slices are then created to fill in the spaces between each slice. These are created through interpolation so that a solid block of data is created in the computer's memory.
The pixels have now become volume pixels, or voxels. These can be loaded into memory, so that the whole volume can be translated, rotated and rendered.
Voxel Opacity Because voxels are 3 dimensional, they have the capability to obscure other voxels. To overcome this problem, each voxel is given an opacity value which determines the voxel's intensity, and therefore, its transparency.
Any voxels with an opacity value of 127 or less, which would appear dark, are rendered completely transparent, therefore creating a more realistic image.
Movement Static 3D renderings wouldn't be of any use to a game, so movement of voxels is required.
A series of renderings must therefore be created. Each one is rotated by a constant increment around a stationary axis. Once this is done for all three dimensions, a rotatable image is created so movement along any plane is possible.
Demo Click here to download a voxel demo [15Kb]
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