[求助]想请高手帮我解释一下

[aneylinwuhui]

I=imread('22.bmp');
[x,y]=size(I);
BW = bwperim(I);

P1=0;
P2=0;
Ny=0;
for i=1:x
for j=1:y
if (BW(i,j)>0)
P2=j;
if ((P2-P1)==1)
Ny=Ny+1;
end
P1=P2;
end
end
end


P1=0;
P2=0;
Nx=0;
for j=1:y
for i=1:x
if (BW(i,j)>0)
P2=i;
if ((P2-P1)==1)
Nx=Nx+1;
end
P1-P2;
end
end
end


SN=sum(sum(BW));
Nd=SN-Nx-Ny;

H=max(sum(I));
W=max(sum(I'));
L=sqrt(2)*Nd+Nx+Ny;

A=bwarea(I);
C=4*pi*A/(L*L);
R=A/(H*W);
E=min(H,W)/max(H,W);


Ath1=10000; Ath2=50000;
Cth=0.5; Rth=0.5; Eth=0.8;


if ((A>=Ath1)&&(A<Ath2))
if ((C>=Cth)&&(R<=Rth)&&(E>Eth))
Cancer_Right=1
end
else if (A>=Ath2)
Cancer_Right=2
else
Cancer_Right=0
end
end

figure(1);
imshow(I);
figure(2);
imshow(BW);


这个程序是检测痰里癌细胞用的 想请高手 帮我解释一下
另外用于识别癌细胞的阈值
Ath1=10000; Ath2=50000;
Cth=0.5; Rth=0.5; Eth=0.8;

是如何得到的 万分的感谢