1. A method of rendering image data for effecting the production of sub-images by a multi-view display, the method comprising the steps of: receiving a first image signal representing a first image comprising 3D image data not yet rendered for multi-view display; spatially filtering the first image signal to provide a second image signal, the second image signal representing a second image, the spatial filtering comprising mapping an image element of the first image to at least one image element of the second image, where a strength of the spatial filter is dependent on a depth of the image element of the first image relative to a reference depth of the first image; and sampling the second image to define a plurality of said sub-images, each sub-image being associated with a different respective view direction of the image.