how to construct huffmandict for an image?

A = imread('lena.jpg'); B = rgb2gray(A); count = imhist(B); p = count/numel(B); [dict,avglen] = huffmandict(count,p);

Error is created Symbols must have unique...

[Nour Alhuda Damer]

are you find a solution???? I have the same error

Answer 1

[Thorsten]

You need to count the occurrences of all unique values; hist does not do that by default, use histu instead:

A = imread('lena.jpg'); 
B = rgb2gray(A);
[values instances] = histu(B);
p = instances/numel(B);
[dict, avglen] = huffmandict(values,p);

with function histu

function [values instances] = histu(x)
%HISTU Count instances of unique values.
%
%   [VALUES INSTANCES] = HISTU(X)
%
%
%Example:
%  I = imread('cameraman.tif');
%  [unique_values number_of_unique_values] = histu(I(:));
%
%Cut & past of code by Roger Stanford posted on 28 Jun, 2011 19:26:05
%http://www.mathworks.com/matlabcentral/newsreader/view_thread/309839  
%
%   [e-mail]  2015-03-27
y = sort(x(:));
p = find([true;diff(y)~=0;true]);
values = y(p(1:end-1));
instances = diff(p);