Dispersion-based Color Projection using Masked Prisms

We present a method for projecting arbitrary color images using a white light source and an optical device with no colored components—consisting solely of one or two prisms and two transparent masks. When illuminated, the first mask creates structured white light that is then dispersed in the prism and attenuated by the second mask to create the color projection. We derive analytical expressions for the mask parameters from the physical components and validate our approach both in simulation and also demonstrate it on a wide variety of images using two different physical setups (one consisting of two inexpensive triangular prisms, and the other using a single rhombic prism). Furthermore, we show that optimizing the masks simultaneously enables obfuscating the image content, and provides a tradeoff between increased light throughput (by up to a factor of three) and maximum color saturation.