Holographic pseudocolouring of gray level information

A new method for the pseudocolouring of transparencies using holographic techniques is presented. An image hologram of a transparency is first registered. When this hologram is illuminated by two waves of different wavelengths, one of the two waves produces a positive holographic image while the other produces a negative transmitted image. The positive and negative images are added at the final image plane resulting in a colour coded image. Conventional white light lamps can be used for the reconstruction and the method can be very easily implemented. A detailed description of the method and some experimental results are shown.