Help for Otsu implementation from C

Peter Otten __peter__ at web.de
Wed Sep 19 13:55:53 CEST 2007


azrael wrote:

> Can somone look at this

> def otsu(hi):
>     fmax=-1.0
>     border=len(hi)
>     for i in range(border):
>         if hi[i]!=0:break
>     for j in range(border-1,0-1,-1):
>         if hi[j] != 0:break
>     s = sum([k*hi[k] for k in range(border)]) n = sum(hi) #
>     product(im.size)
>     n1=n2=csum=0.0
>     for k in range(i,j):
>         n1 += hi[k]
>         n2  = n - n1
>         csum+= k * hi[k]
>         m1 = csum/ n1
>         m2 = (s - csum)/n2

As I said in my previous post, try replacing this line

>         sb = n1 * n2 * (m2 - m1)

with the original

          sb = n1 * n2 * (m1 - m2) * (m1 - m2)

that has been commented out.

>         if sb > fmax:
>             fmax = sb
>             V=k+1
>     print V

> I try to implement it from C from this location.

Personally, I would start with a literal translation and not try to
improve it until it works.

Peter



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