MATLAB: What exactly represents a voxel after loading an image into an array/matrix

3d3d plotsimageimage processing

I know a voxel represents a grid in 3d space, but what exactly voxel is when we load an image(s) in matrix? I am not sure but if I load an image in array/matrix foo, then foo(1,1,1) represents a voxel? Is it necessary to load an images(s) in 3d matrix/array?
Will anybody please clear my basic concept by giving a simplest example, I am newbie to matlab and image processing!

Best Answer

A voxel represents some attribute of your sample at a 3-D location. For example, it could be the radiographic density, or the signal from an MRI instrument, or the color of a fluorescent material, or whatever.