The function of any processor is to map input data to output data. Multi-layer processing systems can implement mappings not feasible in single-layer systems. A layered architecture not only facilitates the implementation of non-linear operations, but also provides successive stages for linear processing. We describe the use of layered architectures in optical processing.
Jason M. Kinser,
James D. Brasher,
Charles F. Hester,
"Layered optical processing architectures", Proc. SPIE 1702, Hybrid Image and Signal Processing III, (1 July 1992); doi: 10.1117/12.60556; https://doi.org/10.1117/12.60556