notes-txt.txt

5x5 gaussian blur

# so this, below, is an approximation or .. what the heck is it?
2  4   5 . .
4  9  12 . .
5  12 15
. .      . .

etc
divided by 159

Seems to say it all, including relationship to sigma

http://www.mvtec.com/halcon/download/documentation/reference/hdevelop/binomial_filter.html

sigma = sqrt(n-1)/2

 n  |  sigma
-------------
 3  |  0.7523
 5  |  1.0317
 7  |  1.2505
 9  |  1.4365
11  |  1.6010
13  |  1.7502
15  |  1.8876
17  |  2.0157
19  |  2.1361
21  |  2.2501
23  |  2.3586
25  |  2.4623
27  |  2.5618
29  |  2.6576
31  |  2.7500
33  |  2.8395
35  |  2.9262
37  |  3.0104


http://books.google.com/books?id=b1s4N98t3ucC&pg=PA124&lpg=PA124&dq=binomial+mask+gaussian&source=web&ots=luMR733hLa&sig=uu7Bh_wt77lrbhTLC5fLtaoyrWA&hl=en&sa=X&oi=book_result&resnum=5&ct=result#PPA124,M1


u = Matrix([1,4,6,4,1])
g = u.transpose() * u
sage: g

[ 1  4  6  4  1]
[ 4 16 24 16  4]
[ 6 24 36 24  6]
[ 4 16 24 16  4]
[ 1  4  6  4  1]

Specifically Hessian theory...

  http://www.cs.utah.edu/~gk/MS/html/node14.html#eq:2dd2