A coloured image has been projected, using a device containing no coloured components.
Researchers from Dartmouth College in the USA and Disney Research Zürich built a photo projection system that uses black images, a white light source and a prism to show colour. The end result, it is said, could be future systems that can trade off colour fidelity, efficiency and resolution to create full-colour projections.
Two masks, created using an off-the-shelf laser printer, are used to reconstruct an image – one on each side of the prism. The first mask uses slits to create a structured pattern of light, which enters the prism and is split into a set of rainbows. One rainbow forms a single ‘pixel’ or value of colour. The second mask reconstitutes the image as it leaves the prism, blocking any colours that do not exist in the image.
By manipulating the mathematical models used to create the masks, the researchers could change the focus of the projection, to optimise saturation or the amount of light returned.
In the future, multispectral projections could be used to go beyond the current RGB model. Dynamic projections could be created with high-resolution greyscale LCD displays to create the masks.
