1. A method of obtaining fiber structure information of a nerve fiber in an object, the method comprising: obtaining image information of voxels of the object, the voxels including a first voxel and second through Nth voxels; setting a tracking start area including the first voxel; setting a tracking processing area to include an adjacent voxel, which is included in the second through Nth voxels and is adjacent to the tracking start area, based on a criteria; determining a similarity between image information of the adjacent voxel and the first voxel; and obtaining the fiber structure information according to the determined similarity.