The image processor presented here was designed for road traffic measurement and uses a four pixels parallelism to process images. It can perform morphological transformations on four, two or one pixel up to 0.3 ms for a 256 x 256 image. It processes binary and grey level images with neighbourhood and arithmetical processors. Its recursive part allows quick reconstructions.
"Parallel Architecture for Mathematical Morphology", Proc. SPIE 1199, Visual Communications and Image Processing IV, (1 November 1989); doi: 10.1117/12.970057; https://doi.org/10.1117/12.970057