huffman encoding for image compression

Question

Nidhi Kumari 2018-10-9

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/423105-huffman-encoding-for-image-compression

评论： Ahmed 2022-12-30

i am using the following code for huffman encoding-

img = imread('xyz.jpg');
Image = rgb2gray(img);
Image = Image(:);
[N M] = size(Image)
Count = zeros(256,1)
for i = 1:N
 for j = 1:M
       Count(Image(i,j)+1)=Count(Image(i,j)+1)+1;
  end
end
prob = Count/(M*N)
symbols = 1:256;
[dict,avglen] = huffmandict(symbols,prob); 
comp = huffmanenco(Image,dict);

but i am getting the following error-

Error using huffmanenco (line 86)
The Huffman dictionary provided does not have the codes for all the input signals.
Error in Untitled2 (line 14)
comp = huffmanenco(Image,dict);

please suggest the required changes

3 个评论
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Swarnali Sadhukhan 2019-5-3

clc;

clear all;

close all;

warning off;

x = imread('brain.jpg');

img=imresize(x,[256 256]);

Image = rgb2gray(img);

%Image = Image(:);

[M N] = size(Image)

Count = 0:255;

for i = 1:M

for j = 1:N

Count(Image(i,j)+1)=Count(Image(i,j)+1)+1;

end

prob = Count/(M*N);

symbols = 0:255;

[dict,avglen] = huffmandict(symbols,prob);

comp = huffmanenco(Image,dict);

figure,imshow(comp); title('encoded.JPG');

Swarnali Sadhukhan 2019-5-3

Error using huffmandict (line 107)

The sum of elements of the probability

vector must be 1

Error in huffman (line 19)

[dict,avglen] =

huffmandict(symbols,prob);

I am getting this error .How can I solve this?

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Answer 1

reb rebz 2019-3-22

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/423105-huffman-encoding-for-image-compression#answer_366869

在 MATLAB Online 中打开

img = imread('xyz.jpg');
Image = rgb2gray(img);
Image = Image(:);
[N M] = size(Image)
Count = zeros(256,1)
for i = 1:N
 for j = 1:M
       Count(Image(i,j)+1)=Count(Image(i,j)+1)+1;
  end
end
prob = Count/(M*N)
symbols = 0:255;
[dict,avglen] = huffmandict(symbols,prob); 
comp = huffmanenco(Image,dict)

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显示 -1更早的评论隐藏 -1更早的评论

Islam Abu Tabikh 2019-5-12

Did you know how ???

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Answer 2

satyendra kumar 2019-3-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/423105-huffman-encoding-for-image-compression#answer_366945

在 MATLAB Online 中打开

i am using the following code for huffman encoding-

clear all
clc
A=imread('cameraman.tif');
A1=double(A(:));
[p,symbols]=hist(A1,unique(A1));
p=p/sum(p);
[dict,avglen] = huffmandict(symbols,p); 
comp = huffmanenco(A1,dict);