Density Pseudocolor Encoding By Holographic Techniques With Three Primary Colors

A new optical method to generate a family of color-coded images using holographic techniques is presented. This method involves the introduction of three primary colors. Thus, this technique overcomes an important limitation of previous holographic techniques. An image hologram of a black-and-white transparency is first registered. This hologram is put in contact with a beam splitter, and the sandwich is illuminated by three partially coherent waves. One wave produces a positive image, a second wave pro-duces an image with reversed contrast, the negative, and the third image corresponds to the product of the positive and the negative. Coding these waves in three primary colors and adding them at the final image plane results in a color-coded image. The principle of the method, theory, and some experimental color results are presented.