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; setting a tracking start area including one or more of first voxels; setting a tracking processing area to include one or more of second voxels, which are adjacent to the tracking start area, based on a criteria; determining similarity between image information of the second voxels and the first voxels; and obtaining the fiber structure information according to the determined similarity, wherein the similarity comprises diffusion direction similarity between diffusion directions of the first voxels and the second voxels, and the fiber structure information is obtained according to a first diffusion time obtained based on the diffusion direction similarity, the first diffusion time including a time of a substance diffusing from the first voxels to the second voxels.