A 3-dimensional image is obtained from a 2-dimensional display by varying the apparent distance of the image from the viewer on a pixel by pixel basis. This can be done by positioning an array of pixel-level optical elements in alignment with the pixels in the image. In a preferred format, each of the optical elements is generally elongate and has a focal length which varies along its length with the result that the point along its length at which light enters the optical element determines the apparent visual distance of the associated pixel from the viewer. In the case of a cathode-ray tube application, controlling the position of entry of the light is done by controlling the electron beam to move a minute distance vertically as it scans horizontally. In a television application, the vertical distance may be determined by a depth component incorporated in the broadcast signal received by a television set. Applications and embodiments relating to computer monitors, film and still printed imagery are also described. Specifically there is provided a method of retrofitting 3-D information to conventional 2-D imaging, comprising the step of digitizing each scene, defining individual objects in the scene, assigning a specified depth to each object in the scene, scanning each pixel in the scene and assigning respective depth components to the pixels according to the specified depth.