An apparatus for generating an image comprises a receiver (101) which receives 3D image data providing an incomplete representation of a scene. A receiver (107) receives a target view vector indicative of a target viewpoint in the scene for the image and a reference source (109) provides a reference view vector indicative of a reference viewpoint for the scene. A modifier (111) generates a rendering view vector indicative of a rendering viewpoint as a function of the target viewpoint and the reference viewpoint for the scene. An image generator (105) generates the image in response to the rendering view vector and the 3D image data.