We modeled an optical system for estimation of the fractal dimension to provide a measure of surface roughness for an entire image and for image segmentation. Although the simulated optical result was similar to that calculated by digital techniques, both suffered from problems known to occur with estimating fractal dimension. Furthermore, the optical estimation did not have as good a resolution as that obtained with digital estimates due primarily to the limited dynamic range of the detector.
Samuel Peter Kozaitis, Rufus H. Cofer, "Optical estimation of fractal dimension for image assessment," Proc. SPIE 1702, Hybrid Image and Signal Processing III, (1 July 1992);