Ostu法 求图像前景背景的类间方差，可是值是单调递增的，为什么

Question

我设置了两个阈值，分别对应canny算子的高低阈值。
double fangcha=0,max=0,s;
int mink=0,maxo=0,t=0;
double x2[32385];
for (int i=0;i {
tj=i;
pj=value[i]/(double)sum;
tp=tj*pj;
E+=tp;
}
for (int k=1;k {
for (int o=k+1;o {
for (int i=0;i {
tj=i;//灰度值
pj=value[i]/(double)sum;//比例
tp=tj*pj;
tpa+=tp;
pk+=pj;
e1k=tpa/(double)pk;
}
for (int i=k+1;i {
tj=i;
pj=value[i]/(double)sum;
tp=tj*pj;
tpb+=tp;
pko+=pj;
e2ko=tpb/(double)pko;
}
for (int i=o+1;i {
tj=i;
pj=value[i]/(double)sum;
tp=tj*pj;
tpc+=tp;
po+=pj;
e3o=tpc/(double)po;
}
s=pk+pko+po;
fangcha=(e1k-E)*(e1k-E)*pk+(e2ko-E)*(e2ko-E)*pko+(e3o-E)*(e3o-E)*po;
x2[t]=fangcha;
t++;
if (fangcha>max)
{
max=fangcha;
mink=k;
maxo=o;
}
}
}

Answer 1

参考：http://blog.csdn.net/zhangfuliang123/article/details/70821455