Provided are a method and an apparatus for image processing. A scene includes a low resolution depth image and a high resolution color image. A depth image up-scaler up-scales the depth image using an interpolation so as to improve the resolution of the depth image. A color-depth similarity based filter removes noise from the up-scaled depth image using the color image and the up-scaled depth image. A boundary sharpening filter converts a boundary between objects in the up-scaled depth image into a clearer boundary. The resolution of the depth image may increase to the level of the resolution of the color image by means of the depth image up-scaler, the color-depth similarity based filter and the boundary sharpening filter, and the depth of each pixel in the depth image may be adjusted.