Why did you post this? There is no question. Did you mean for this to go into the File Exchange instead of here? What are we supposed to do with this?
can anyone help me in the calculation of the compression ratio for the code below
2 views (last 30 days)
Show older comments
%-------script sampletestv2----------------
clc;
% This is a test program that tests the EZW encoder and decoder
% matrix X is an example matrix same as Shapiro's paper given
% Written by xiangang li
%
% This function calls:
% dominantpass.m
% subordinatepass.m
% checkdescents1.m
% checkchildren.m
% mapping.m
X=[63 -34 49 10 7 13 -12 7;
-31 23 14 -13 3 4 6 -1;
15 14 3 -12 5 -7 3 9;
-9 -7 -14 8 4 -2 3 2;
-5 9 -1 47 4 6 -2 2;
3 0 -3 2 3 -2 0 4;
2 -3 6 -4 3 6 3 6;
5 11 5 6 0 3 -4 4];
X0=X;
Y0=max(X);
Y1=max(Y0);
for i=0:20;
if 2^i<=Y1 & 2^i>0.5*Y1;
threshold=2^i; % get initial threshold T0;
initialthreshold=threshold; % get initial threshold T0;
laststeplevel=i+1;% last step level
break;
end;
end;
sublist=[];
sub_list=[];
[xx,yy]=size(X);
A=mappingv2(xx);
[m,n]=size(A);
global N; % Let Morton scanorder vector as a global variable
N=zeros(m*n,2);
for i=1:m,
for j=1:n,
N(A(i,j),1)=i;
N(A(i,j),2)=j;
end
end
order=1;
while threshold ~= 0.5, % if threshold~=1, do dominantpass and subordinatepass.
threshold
%Dominant Pass
[D,X,sublist,sub_list] = dominantpassv2(X,threshold,sublist,sub_list);
DD{order}=D
significantlist{order}=sub_list;
%Subordinate pass
threshold=threshold/2;
if threshold ==0.5,
break;
end
S = subordinatepassv2(sublist,threshold);
SS{order}=S
order=order+1;
end
%*********************************%
%*********EZW decoder*************%
%*********************************%
global N;
[m,n]=size(N);% the size of initial image
% m is the pixels of initial image
XX=zeros(sqrt(m)); % initialize the reconstructured image to zero;
threshold=initialthreshold; % initial theshold ;
sublist=[]; % sublist is the new position matrix
% for all significant coefficients 'p' and 'n';
for level=1:laststeplevel,
RR=zeros(size(XX)); % reference matrix RR;
[a,b]=size(DD{level}); % ?
% dominant pass
i=1; j=1;
while j<=b,
if RR(N(i,1),N(i,2))==0
if DD{level}(j)=='p'
if threshold==1
XX(N(i,1),N(i,2))=threshold;
else
XX(N(i,1),N(i,2))=1.5*threshold;
end
end
if DD{level}(j)=='n'
if threshold==1
XX(N(i,1),N(i,2))=-threshold;
else
XX(N(i,1),N(i,2))=-1.5*threshold;
end
end
if DD{level}(j)=='t'& A(N(i,1),N(i,2))<=m/4
RR=checkchildrenv2(i,RR);% all zerotree's descendants are set to 1.
end
RR(N(i,1),N(i,2))=1; %reference matrix =1;
i=i+1;
j=j+1;
else i=i+1;
end
end
% subordinate pass
[xx,yy]=size(significantlist{level});
threshold=threshold/2;
for i=1:xx,
if level==laststeplevel|threshold==0.5
break
end
if SS{level}(i)==1
if XX(sub_list(i,1),sub_list(i,2))>0;
XX(sub_list(i,1),sub_list(i,2))= fix(XX(sub_list(i,1),sub_list(i,2))+ threshold/2);
else
XX(sub_list(i,1),sub_list(i,2))= fix(XX(sub_list(i,1),sub_list(i,2))-threshold/2);
end
end
if SS{level}(i)==0
if XX(sub_list(i,1),sub_list(i,2))>0;
XX(sub_list(i,1),sub_list(i,2))= fix(XX(sub_list(i,1),sub_list(i,2))-threshold/2);
else
XX(sub_list(i,1),sub_list(i,2))= fix(XX(sub_list(i,1),sub_list(i,2))+threshold/2);
end
end
end
threshold
level
XX
end
initialiamge=X0
reconstructedimage=XX
difference=XX-X0
whos
%------function mappingv2-------------------
function A = mappingv2(n)
if n == 2
A = [1 2; 3 4];
else
B = mappingv2(n/2);
A = [B B+(n/2)^2; B+(n/2)^2*2 B+(n/2)^2*3];
end
%------function dominantpassv2-----------------
function [D,X,sublist,sub_list] = dominantpassv2(X,threshold,sublist,sub_list)
% Dominant pass function
D=[];
global N;
[m,n]=size(X);
% X is the coefficients matrix
R=zeros(m); % matrix R is a reference matrix, same size as X; '0' means
%this coefficient is not a descendant from zerotree root;
[a,b]=size(N);
if abs(X(1,1))>=threshold % X(1,1) is DC coefficient
sublist=[sublist, abs(X(1,1))]; % put significant coefficients's value to sublist
sub_list=[sub_list;N(1,1),N(1,2)];% put the significant coefficients' position in sub_list
if X(1,1)>0;
D=[D,'p'];
else D=[D,'n'];
end
X(1,1)=0;
else D=[D,'z'];
end
for k=2:4,
if abs(X(N(k,1),N(k,2)))>=threshold,
sublist=[sublist, abs(X(N(k,1),N(k,2)))];
% append this significant coefficient to the subordinate list;
sub_list=[sub_list;N(k,1),N(k,2)];
if X(N(k,1),N(k,2))>0 % determine the sign
D=[D,'p']; % >0,assign a "p"
else D=[D,'n'];% <0,assign a "n"
end
X(N(k,1),N(k,2))=0;
% the significent coefficients is replaced by a '0' in the coefficients matrix
else
% 2,3,4 has no parents,just check its descendants.
result = checkdescendants1v2( k,X,threshold,0);
if result==1
D=[D,'z'];
else
D=[D,'t'];
R(N(k,1),N(k,2))=1; % Zerotree, make all its descendants
R=checkchildrenv2(k,R); % refference matrix component to 1.
end
end
end
for k=5:a,
if abs(X(N(k,1),N(k,2)))>=threshold,
sublist=[sublist, abs(X(N(k,1),N(k,2)))];
sub_list=[sub_list;N(k,1),N(k,2)];
if X(N(k,1),N(k,2))>0, % determine the sign
D=[D,'p']; % >0,assign a "p"
else D=[D,'n'];% <0,assign a "n"
end
X(N(k,1),N(k,2))=0;
elseif R(N(k,1),N(k,2))==0
result = checkdescendants1v2( k,X,threshold,0);
% Check its has significant descendants?
if result==1,
D=[D,'z']; % isolated zero
else D=[D,'t'];% zerotree
R(N(k,1),N(k,2))=1;
R=checkchildrenv2(k,R);
% if zerotree, reference matrix coefficients=1
end
end
end
%-------function subordinantpassv2-------
function S = subordinatepassv2(sublist,threshold)
S=[];
[m,n]=size(sublist);
for i=1:n;
if bitand(sublist(1,i),threshold)==threshold,
%if sublist(1,i)>=threshold,
S=[S,1];
%sublist(1,i)=sublist(1,i)-threshold;
else S=[S,0];
end
end
%-------function checkdescendantv2------------
function result = checkdescendants1v2(j,X,threshold,result)
% initial set result=0
% if the result=1, means that a coefficient has at least
% 1 significant descendant.
global N
[m,n]=size(N);
for i=(4*j-3):4*j;
if result==1 | i > m
break;
end;
if abs(X(N(i,1),N(i,2)))>=threshold
result=1;
break;
else
result=checkdescendants1v2(i,X,threshold,result);
end;
end;
%------function checkchildrenv2------------
function RR=checkchildrenv2(j,RR)
% if a symbol 't' is encounted, then make all its descendants in reference
% matrix RR's components equal 1---ZEROTREES
global N
[m,n]=size(N);
for i=(4*j-3):4*j;
if i<=m,
RR(N(i,1),N(i,2))=1;
RR=checkchildrenv2(i,RR);
end
end;
%------output--------
threshold =
32
DD =
Columns 1 through 2
'pnztpttttztttttttptt' 'ztnptttttttt'
Columns 3 through 5
[1x56 char] [1x56 char] [1x56 char]
Columns 6 through 7
'zzzttztttztttttnnttt' [1x256 char]
Column 8
'ztzttzttzttttttztttztzttttzttptt'
SS =
Columns 1 through 3
[1x4 double] [1x6 double] [1x20 double]
Columns 4 through 6
[1x41 double] [1x59 double] [1x65515 double]
Column 7
[1x65535 double]
threshold =
16
DD =
Columns 1 through 2
'pnztpttttztttttttptt' 'ztnptttttttt'
Columns 3 through 5
[1x56 char] [1x56 char] [1x56 char]
Columns 6 through 7
'zzzttztttztttttnnttt' [1x256 char]
Column 8
'ztzttzttzttttttztttztzttttzttptt'
SS =
Columns 1 through 3
[1x4 double] [1x6 double] [1x20 double]
Columns 4 through 6
[1x41 double] [1x59 double] [1x65515 double]
Column 7
[1x65535 double]
threshold =
8
DD =
Columns 1 through 2
'pnztpttttztttttttptt' 'ztnptttttttt'
Columns 3 through 5
[1x56 char] [1x56 char] [1x56 char]
Columns 6 through 7
'zzzttztttztttttnnttt' [1x256 char]
Column 8
'ztzttzttzttttttztttztzttttzttptt'
SS =
Columns 1 through 3
[1x4 double] [1x6 double] [1x20 double]
Columns 4 through 6
[1x41 double] [1x59 double] [1x65515 double]
Column 7
[1x65535 double]
threshold =
4
DD =
Columns 1 through 2
'pnztpttttztttttttptt' 'ztnptttttttt'
Columns 3 through 5
[1x56 char] [1x56 char] [1x56 char]
Columns 6 through 7
'zzzttztttztttttnnttt' [1x256 char]
Column 8
'ztzttzttzttttttztttztzttttzttptt'
SS =
Columns 1 through 3
[1x4 double] [1x6 double] [1x20 double]
Columns 4 through 6
[1x41 double] [1x59 double] [1x65515 double]
Column 7
[1x65535 double]
threshold =
2
DD =
Columns 1 through 2
'pnztpttttztttttttptt' 'ztnptttttttt'
Columns 3 through 5
[1x56 char] [1x56 char] [1x56 char]
Columns 6 through 7
'zzzttztttztttttnnttt' [1x256 char]
Column 8
'ztzttzttzttttttztttztzttttzttptt'
SS =
Columns 1 through 3
[1x4 double] [1x6 double] [1x20 double]
Columns 4 through 6
[1x41 double] [1x59 double] [1x65515 double]
Column 7
[1x65535 double]
threshold =
1
DD =
Columns 1 through 2
'pnztpttttztttttttptt' 'ztnptttttttt'
Columns 3 through 5
[1x56 char] [1x56 char] [1x56 char]
Columns 6 through 7
'zzzttztttztttttnnttt' [1x256 char]
Column 8
'ztzttzttzttttttztttztzttttzttptt'
threshold =
16
level =
1
XX =
56 -40 56 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 40 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
threshold =
8
level =
2
XX =
60 -36 52 0 0 0 0 0
-28 20 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 44 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
threshold =
4
level =
3
XX =
62 -34 50 10 0 14 -14 0
-30 22 14 -14 0 0 0 0
14 14 0 -14 0 0 0 10
-10 0 -14 10 0 0 0 0
0 10 0 46 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 10 0 0 0 0 0 0
threshold =
2
level =
4
XX =
63 -35 49 11 7 13 -13 7
-31 23 15 -13 0 5 7 0
15 15 0 -13 5 -7 0 9
-9 -7 -15 9 5 0 0 0
-5 9 0 47 5 7 0 0
0 0 0 0 0 0 0 5
0 0 7 -5 0 7 0 7
5 11 5 7 0 0 -5 5
threshold =
1
level =
5
XX =
63 -34 49 10 7 13 -12 7
-31 23 14 -13 3 4 6 0
15 14 3 -12 5 -7 3 9
-9 -7 -14 8 4 -2 3 2
-5 9 0 47 4 6 -2 2
3 0 -3 2 3 -2 0 4
2 -3 6 -4 3 6 3 6
5 11 5 6 0 3 -4 4
threshold =
0.5
level =
6
XX =
63 -34 49 10 7 13 -12 7
-31 23 14 -13 3 4 6 -1
15 14 3 -12 5 -7 3 9
-9 -7 -14 8 4 -2 3 2
-5 9 -1 47 4 6 -2 2
3 0 -3 2 3 -2 0 4
2 -3 6 -4 3 6 3 6
5 11 5 6 0 3 -4 4
initialiamge =
63 -34 49 10 7 13 -12 7
-31 23 14 -13 3 4 6 -1
15 14 3 -12 5 -7 3 9
-9 -7 -14 8 4 -2 3 2
-5 9 -1 47 4 6 -2 2
3 0 -3 2 3 -2 0 4
2 -3 6 -4 3 6 3 6
5 11 5 6 0 3 -4 4
reconstructedimage =
63 -34 49 10 7 13 -12 7
-31 23 14 -13 3 4 6 -1
15 14 3 -12 5 -7 3 9
-9 -7 -14 8 4 -2 3 2
-5 9 -1 47 4 6 -2 2
3 0 -3 2 3 -2 0 4
2 -3 6 -4 3 6 3 6
5 11 5 6 0 3 -4 4
difference =
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
Name Size Bytes Class Attributes
A 8x8 512 double
D 1x20 40 char
DD 1x8 1496 cell
N 64x2 1024 double global
RR 8x8 512 double
S 1x59 472 double
SS 1x7 1049860 cell
TC_1 1x22 176 double
X 8x8 512 double
X0 8x8 512 double
XX 8x8 512 double
XXX 256x256 524288 double
Y 256x256 65536 uint8
Y0 1x8 64 double
Y1 1x1 8 double
a 1x1 8 double
b 1x1 8 double
difference 8x8 512 double
i 1x1 8 double
initialiamge 8x8 512 double
initialthreshold 1x1 8 double
j 1x1 8 double
laststeplevel 1x1 8 double
level 1x1 8 double
m 1x1 8 double
map 256x3 6144 double
n 1x1 8 double
order 1x1 8 double
reconstructedimage 8x8 512 double
significantlist 1x8 2100672 cell
sub_list 61x2 976 double
sublist 0x0 0 double
threshold 1x1 8 double
xx 1x1 8 double
yy 1x1 8 double
>>
Answers (0)
See Also
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
You can also select a web site from the following list
Americas
- América Latina (Español)
- Canada (English)
- United States (English)
Europe
- Belgium (English)
- Denmark (English)
- Deutschland (Deutsch)
- España (Español)
- Finland (English)
- France (Français)
- Ireland (English)
- Italia (Italiano)
- Luxembourg (English)
- Netherlands (English)
- Norway (English)
- Österreich (Deutsch)
- Portugal (English)
- Sweden (English)
- Switzerland
- United Kingdom(English)
Asia Pacific
- Australia (English)
- India (English)
- New Zealand (English)
- 中国
- 日本Japanese (日本語)
- 한국Korean (한국어)