1. A medical image processing unit comprising: a volume data input unit for inputting three-dimensional volume data from a modality; a volume rendering unit for inputting light source information indicating a shape, position, and orientation of a light source, inputting texture information indicating a pattern and a reflection property of an object irradiated with a light source, generating a two-dimensional rendered image by converting the three-dimensional volume data, which is input to the volume data input unit, into two-dimensional volume data, and correcting the two-dimensional rendered image based on the input light source information and texture information; a depth information generator for generating depth information indicative of length from a virtual view position in a virtual three-dimensional space to the three-dimensional volume data on the basis of the three-dimensional volume data which is input to the volume data input unit; an anti-aliasing unit for identifying a target in the rendered image generated by the volume rendering unit based on the depth information generated by the depth information generator and executing anti-aliasing processing on an edge portion of the identified target; a display unit for displaying an image including the target, on which the anti-aliasing processing has been executed, as a rendered image; an oil layer image generator for generating an oil layer image based on the input light source information and texture information; and an image synthesizer for synthesizing the oil layer image generated by the oil layer image generator and the rendered image generated by the volume rendering unit and displaying a synthesized image as the rendered image on the display unit.