Three dimensional image data is provided which includes data representing a first image which specifically may be a background image. A mixed image which is a combination of the first image and a second image which specifically may be a foreground image, a transparency map related to the mixed image comprising transparency values for pixels of the mixed image and a depth indication map for the mixed image comprising depth indication values for pixels of the mixed image. The use of a mixed image may allow three dimensional processing while at the same time allowing 2D backwards compatibility. Image quality around image objects may be improved by modifying transparency values in response to depth indication values and/or depth indication values in response to transparency values. Specifically, an improved alignment of transitions of depth indication values and transparency values may provide improved three dimensional foreground image object edge data.