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Gaussian Blur

Blitz3D Forums/Blitz3D Programming/Gaussian Blur

JBR(Posted 2006) [#1]
Hi, have my matrix 13 by 13 which means 169 calculations per image pixel.
This is slow.

I read that the method is 'Linearly Seperable' which would mean i could use 13+13 = 26 calculations per pixel.
This is faster.

Problem is I don't know exactly how to do this.
Do I use the middle lines from the matrix?

Thanks
Jim


b32(Posted 2006) [#2]
Maybe it means you should first you apply the horizontal blur (13 calculations), and then the vertical blur (again 13) ?


Mr Snidesmin(Posted 2006) [#3]
Why not just do an approximation and only blur with nearby pixels?

Eg:
dim mat#(12, 12)
dim matblurred#(12, 12)

For x = 0 To 12
For y = 0 To 12
   mat#(x, y) = Rnd()
   matblurred(x, y) = mat(x, y) 
Next
Next


For x = 1 To 11
For y = 1 To 11
	n# = 0
	n = n + mat#(x-1, y-1)
	n = n + mat#(x-1, y)
	n = n + mat#(x-1, y+1)
	n = n + mat#(x, y-1)
	n = n + mat#(x, y)
	n = n + mat#(x, y+1)
	n = n + mat#(x+1, y-1)
	n = n + mat#(x+1, y)
	n = n + mat#(x+1, y+1)
	matblurred(x, y) = n / 9#
Next
Next