A holographic image projection system for projecting an image at an acute angle onto a surface includes: a spatial light modulator (SLM) to display a hologram; an illumination system to illuminate the displayed hologram; projection optics to project light from the illuminated displayed hologram onto the surface at an acute angle form the image; and a processor having an input to receive input image data for display and an output to provide hologram data for the SLM, wherein the processor is configured to: input image data and convert this to target image data; generate from the target image data hologram data for display as a hologram on the SLM to reproduce a target image; and wherein the target image is distorted to compensate for the projection of the hologram at an acute angle to form the image.