1. A method of providing three dimensional image data for use in rendering image elements of at least one view of the three dimensional image data, the method comprising: providing a 2D first image, as a background image providing a mixed image by overlaying a second image, as a foreground image, on the first image, said overlaying incorporating transparency data for the second image, wherein the mixed image includes background image objects and foreground image objects; providing a transparency map related to the mixed image, the transparency map comprising transparency values for pixels of the mixed image; providing a first depth indication map for the mixed image, the first depth indication map comprising depth indication values for pixels of the mixed image; modifying values of a first set of values in an image region of the mixed image determined between a transition point in the transparency map and a transition point in the first depth indication map based on a second set of values, wherein the first set of values comprising a set of values corresponding to one of: the transparency values and the depth indication values, and the second set of values comprising a set of values corresponding to one of: the depth indication values and the transparency values, wherein the modified values of the first set of values represent modification of the first set of values dependent on the second set of values; and generating the three dimensional image data, said three-dimensional image data comprising the first image, the mixed image, the transparency map and the first depth indication map.