Linear shift-invariant filters
	Both cross-correlation and convolution filters have the following properties • linear: – how about scale?  Is the following true? • shift-invariant:  same operation applied for every x,y in f Any filter with these properties (LSI) may be written as a cross-correlation • Is this also true for convolution? Convolution has nice properties in the Fourier Domain • we won’t cover this, but see Forsyth Chap. 8.3 for a nice discussion