huffman encoding for image compression

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Nidhi Kumari
Nidhi Kumari el 9 de Oct. de 2018
Comentada: Ahmed el 30 de Dic. de 2022
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 comentarios
Swarnali Sadhukhan
Swarnali Sadhukhan el 3 de Mayo de 2019
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
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
Swarnali Sadhukhan el 3 de Mayo de 2019
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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Respuestas (3)

reb rebz
reb rebz el 22 de Mzo. de 2019
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)

satyendra kumar
satyendra kumar el 23 de Mzo. de 2019
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);

SS
SS el 11 de Oct. de 2019
can i use huffman coding for both lossy and lossless image compression??

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