A light engine arranged to form an image visible from a viewing window, the light engine comprising a display device for displaying a hologram of the image and spatially modulating light based on the hologram. The hologram is configured to angularly distribute spatially-modulated light of the image based on position of image content, where angular channels of the spatially-modulated light correspond with respective continuous regions of the image. The light engine further comprises a waveguide pupil expander for receiving the spatially-modulated light and providing a plurality of light propagation paths for the spatially-modulated light from the display device to the viewing window, and a control device between the waveguide and the viewing window. The control device comprises an aperture arranged such that a first viewing position receives a first channel of spatially-modulated light and a second viewing position receives a second channel of spatially-modulated light.