# Basic Terminologies

From CRIPTWiki

Pixel:

- A square display unit. All 2D pictures are composed of pixels.
- A 3 pixel by 3 pixel pictures contains 9 pixels.
- Pixel is flat with unit length of 1 and width of 1.

Voxel:

- A cube display unit.All 3D data sets are made from voxels.
- A 3 voxel by 3 voxel by 3 voxel matrix contains 27 voxels.
- voxel is 3D and has length of 1 and width of 1 and height of 1.

Two Dimensional Imaging (eg. Histology): Data measurment including length and width.

- NOTE: histology is always considered 2D but it does include height. Hence if you are given many histological slices, you can reconstitute them into a 3D data set as well.

Three Dimensional Imaging (eg. Modeling, plastic, virtual,etc): Data measurement including height, length and width.

- Note: Model is considered 3D most of the time. However, once you start dynamically swapping 3D data sets (eg. a heart beating through time). Hence, a series of 3D data sets of relevant structures are considered 4D.

Four Dimensional Imaging: Data measurement including height, length, width and time. Time is the key here. This is the hardest dataset to work with. Make sure you recycle lable should it be necessary.

CT/CAT MRI fMRI

Surface Generation Volumetric Rendering Isosurface