what is the size of patch in pmvs?

i try to make pmvs in matlab with

Yasutaka Furukawa et al.'s Paper "Accurate, Dense, and Robust Multi-View Stereopsis"

he say

'The extent of the rectangle is chosen so that the smallest axis-aligned square in R(p) containing its image projection is of size μ×μ pixels in size(μ is either 5 or 7 in all of our experiments).'

i don't understand what it mean

i think i need some example about it can i get some example about that?

The patch extent is calculated in the following way:

1. Project patch p on to R(p) and get the patch in the image R(p), so now we have the pixels in the image R(p) that corresponds to the patch p - lets call this sub image Ip.
2. Take Ip and find the smallest square that enclose Ip - lets call it S(Ip). Axis aligned means that the square isn't oriented. See the difference between Oriented bounding box and Axis aligned bounding box
3. The size of S(Ip) needs to be μ X μ pixels.