Real-time optical image subtraction using dynamic holographic interference in photorefractive media.

A method of optical image subtraction is proposed. It provides parallel and real-time amplitude subtraction of two images by using holographic interference in photorefractive media. This new method provides an automatic phase shift of 180 deg between the two images and may be viewed as a real-time implementation of Gabor’s image-subtraction technique. Some experimental results are presented and discussed.