1. An image processing apparatus, comprising: a processor to control one or more processor-executable units; a splitting unit to split a first space within an input three-dimensional (3D) model into a plurality of subspaces in order to generate an acceleration structure of the input 3D model; and a decision unit to set a subspace determined as having a relatively high probability of including a ray progress path among the plurality of subspaces, as a child node having a relatively high traversal priority in the acceleration structure among a plurality of child nodes.