Computing SSD/SSE using pattern with omitted pixel The goal is to compute a weighted SSD over a small neighborhood of pixels (Np pattern in the following figure)

I want to know why the bottom-right pixel is omitted: 


It is said that to enable SSE-optimized processing but I didn't really understand it!

This is the link for the PDF: http://vision.in.tum.de/_media/spezial/bib/engel2016dso.pdf

and it is the figure - 4
By excluding the bottom right pixel, the authors only need to process 8 pixels which can be stored in eight SSE registers (xmm0 through xmm7).
https://en.wikipedia.org/wiki/Streaming_SIMD_Extensions#Registers