1. An image processing apparatus comprising: a computer processor comprising: a depth estimation unit which estimates depth of an input three dimensional (3D) image; a text area detection unit which detects a text area included in the 3D image; a mask generation unit which generates a text mask corresponding to the detected text area; and a depth correction unit which corrects a depth of the text area to be a first depth value based on the estimated depth of the input 3D image and the generated text mask.