# Otsu algorithm (two)

Source: Internet
Author: User

% using the Otsu algorithm for binary images

Close All;clear ALL;CLC

%%

I = Imread (' c.jpg ');

Scoreimage0=rgb2gray (I);

Scoreimage=double (SCOREIMAGE0);

[Height,length]=size (Scoreimage);

Totalpixel=height*length;

% Maxpixnumber=max (max (scoreimage));

This place is not calculated for future convenience, but the default maximum is 255.

Pixelcount=zeros (1,256);% counts the number of individual pixel values

% 0-256

For I=1:length

For J=1:height

Number=scoreimage (j,i) +1;

Pixelcount (number) =pixelcount (number) +1;

End

End

% probability

Pf=pixelcount/totalpixel;

% forward cumulative probability density function

Cpf=zeros (1,256);

CPF (1) =PF (1);

For i=2:256

CPF (i) =CPF (i-1) +PF (i);

End

% post-cumulative probability density function

Bpf=zeros (1,256);

BPF (=PF) (256);

For J=256:-1:2

BPF (J-1) =BPF (j) +PF (j-1);

End

% forward Cumulative expectations

Meanforward=zeros (1,256);

Meanforward (1) = 1;

For i=2:256

Meanforward (i) =meanforward (i-1) * (CPF (i-1)/CPF (i)) + (PF (i)/CPF (i)) *i;

End

% back to cumulative expectation

Meanback=zeros (1,256);

Meanback (Max (scoreimage)) =max (Max (scoreimage));

For I=max (Max (scoreimage)): -1:2

Meanback (i-1) =meanback (i) * (BPF (i)/BPF (i-1)) + (PF (i-1)/BPF (i-1)) * (i-1);

End

Delta=cpf.*bpf.* (meanforward-meanback). ^2;

[Value,index]=max (delta);

% Returns a logical image

binariedimage=scoreimage>index;

Figure

Subplot (1,2,1); Imshow (SCOREIMAGE0); Title (' original image ');

Subplot (1,2,2); Imshow (binariedimage); Title (' Processing chart ');

Here is the original: http://blog.sina.com.cn/s/blog_98ddf7cb0101chu3.html

Otsu algorithm (two)

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