The transmission properties of some bacteriorhodopsin-film spatial light modulators are uniquely suited to allow nonlinear optical image-processing operations to be applied to images with multiplicative noise characteristics. A logarithmic amplitude-transmission characteristic of the film permits the conversion of multiplicative noise to additive noise, which may then be linearly filtered out in the Fourier plane of the transformed image. I present experimental results demonstrating the principle and the capability for several different image and noise situations, including deterministic noise and speckle. The bacteriorhodopsin film studied here displays the logarithmic transmission response for write intensities spanning a dynamic range greater than 2 orders of magnitude.
© 1995 Optical Society of America
Original Manuscript: October 17, 1994
Revised Manuscript: March 15, 1995
Published: August 10, 1995
John D. Downie, "Nonlinear coherent optical image processing using logarithmic transmittance of bacteriorhodopsin films," Appl. Opt. 34, 5210-5217 (1995)