Line | |
---|
1 | % isptnorm ISotropic PoinT NORMalization |
---|
2 | % |
---|
3 | % [xnorm,T] = isptnorm(x); |
---|
4 | % x ... [N x dim] coordinates |
---|
5 | % |
---|
6 | % xnorm ... normalized coordinates |
---|
7 | % T ... transformation matrix used |
---|
8 | % |
---|
9 | % T. Svoboda, 5/2001 |
---|
10 | |
---|
11 | |
---|
12 | function [xnorm,T] = isptnorm(x); |
---|
13 | |
---|
14 | |
---|
15 | % data dimension |
---|
16 | dim = size(x,2); |
---|
17 | N = size(x,1); |
---|
18 | |
---|
19 | % make homogenous coordinates |
---|
20 | x(:,dim+1) = ones(N,1); |
---|
21 | |
---|
22 | % compute sum of square diferences |
---|
23 | for i=1:dim, |
---|
24 | ssd(:,i) = (x(:,i)-mean(x(:,i))).^2; |
---|
25 | end |
---|
26 | |
---|
27 | scale = (sqrt(dim)*N) / (sum(sqrt(sum(ssd')))); |
---|
28 | |
---|
29 | T = zeros(dim+1); |
---|
30 | |
---|
31 | for i=1:dim, |
---|
32 | T(i,i) = scale; |
---|
33 | T(i,dim+1) = -scale*mean(x(:,i)); |
---|
34 | end |
---|
35 | T(dim+1,dim+1) = 1; |
---|
36 | |
---|
37 | xnorm = T*x'; |
---|
38 | xnorm = xnorm'; |
---|
39 | % return nonhomogenous part of the points coordinates |
---|
40 | xnorm = xnorm(:,1:dim); |
---|
41 | |
---|
42 | |
---|
43 | |
---|
Note: See
TracBrowser
for help on using the repository browser.