1. An image processing apparatus comprising: a processor; a ray tracer to perform ray tracing with respect to a plurality of first rays, selected from among all rays, for photon mapping; a sampling unit to sample a ray space using the plurality of first rays traced by the ray tracer; and a reconstructor to reconstruct the sampled ray space to provide at least one second ray for generating a pseudo photon, using the plurality of first rays traced by the ray tracer.