%*******************************************************************
% Region Based Stereo Matching Algorithm by Region Growing
% method explanied in the "Obtaining Depth Maps From Color Images
% By Region Based Stereo Matching Algorithms". It simplified to line
% growing at row directions
%
% It uses stereo color image pairs. Right camera image is loaded into XR array
% and left camera image is loaded into XL array. You can set Disparity search
% range by DisparityRange.
%
%
% Programmer: B. Baykant ALAGZ
% Ver.1.0 date: 09.2008
%******************************************************************
clear all
tic
% User can set DisparityRange and matching variable.
%You can set upper bound of disparity search range by dmax
dmax=40;
%Threshold for line growing
LineGrowingTreshold=10;
% Alfa tolerance coefficient for eliminating unreliable estimation
Alfa=1;
% Stereo Camera System Parameter for dept map calcualtion
% foc: focal length of cameras in unit of cm
foc=30;
% T: distance between stereo camera pair in unit of cm
T=20;
%Loading Right image to XR and Left image to XL
[XR,MAP] = IMREAD('view5m.png');
[XL,MAP] = IMREAD('view1m.png');
%------------------ END of USER SETTINGS----------------------
% auto-presettings for the program
XR=double(XR);
XL=double(XL);
[m n p]=size(XR);
disparity=zeros(m,n);
regMap=zeros(m,n);% Show status of point. 0: not tested, 1:Belong to a region
% 2:A root point 3: Useless(Idle) point
IndexI=1;
IndexJ=1;
State=0;
Edis=100000*ones(m,n);
% Red,Green,Blue deerleri birletirip ortalamas alnarak gri resim elde
% edilir.
for i=2:m
fprintf ('Scanned row for line growing: %d\n',i);
for j=2:n-1-dmax
% Root point selection process
% State=0 indicates finding a root
if State==0
if regMap(i,j)==0
for d=0:dmax
% Error energy calculated along line lenght of 3.(o-*-o)
ErrorEnergy=(1/9)*[(XR(i,j,1)-XL(i,j+d,1))^2+(XR(i,j,2)-XL(i,j+d,2))^2+(XR(i,j,3)-XL(i,j+d,3))^2+(XR(i,j-1,1)-XL(i,j-1+d,1))^2+(XR(i,j-1,2)-XL(i,j-1+d,2))^2+(XR(i,j-1,3)-XL(i,j-1+d,3))^2+(XR(i,j+1,1)-XL(i,j+1+d,1))^2+(XR(i,j+1,2)-XL(i,j+1+d,2))^2+(XR(i,j+1,3)-XL(i,j+1+d,3))^2];
if ErrorEnergy < Edis(i,j)
disparity(i,j)=d;
Edis(i,j)=ErrorEnergy;
State=1;
IndexI=i;
IndexJ=j;
if LineGrowingTreshold<ErrorEnergy
regMap(i,j)=3; % Mark as idle point
disparity(i,j)=0;
else
regMap(i,j)=2;% Mark as root points
end
end
end%For d
end
end% if
% Region growing process
% State=1 indicates growing the line
while (State==1)
State=0;
k=IndexI;
for w=IndexJ+1:(n-1-dmax)
if k>1 && w>1 && k<(m-1) && w<(n-1-dmax) && regMap(k,w)==0
% Error energy calculated along line lenght of 3.(o-*-o)
ErrorEnergy=(1/9)*[(XR(k,w,1)-XL(k,w+disparity(IndexI,IndexJ),1))^2+(XR(k,w,2)-XL(k,w+disparity(IndexI,IndexJ),2))^2+(XR(k,w,3)-XL(k,w+disparity(IndexI,IndexJ),3))^2+(XR(k,w-1,1)-XL(k,w-1+disparity(IndexI,IndexJ),1))^2+(XR(k,w-1,2)-XL(k,w-1+disparity(IndexI,IndexJ),2))^2+(XR(k,w-1,3)-XL(k,w-1+disparity(IndexI,IndexJ),3))^2+(XR(k,w+1,1)-XL(k,w+1+disparity(IndexI,IndexJ),1))^2+(XR(k,w+1,2)-XL(k,w+1+disparity(IndexI,IndexJ),2))^2+(XR(k,w+1,3)-XL(k,w+1+disparity(IndexI,IndexJ),3))^2];
if ErrorEnergy < LineGrowingTreshold
disparity(k,w)=disparity(IndexI,IndexJ);
Edis(k,w)=ErrorEnergy;
State=1;
IndexIa=k;
IndexJb=w;
regMap(k,w)=1;% Mark as associated region point
end
end
end %For w
if State==1
IndexI=IndexIa;
IndexJ=IndexJb;
end
%figure(1)
%imagesc(regMap);
%pause(1);
end %While
end %For i
end %For j
% clear 1000000 pre-setting in Edis
for k=1:m
for l=1:n
if Edis(k,l)==100000
Edis(k,l)=0;
end
end
end
% extracting calculated zone
nx=n-dmax;
for k=2:m-1
for l=2:nx-1
disparityx(k,l)=disparity(k,l);
%Edisx(k,l)=Edis(k,l);
regMapx(k,l)=regMap(k,l);
XLx(k,l)=XL(k,l);
XRx(k,l)=XR(k,l);
top=0;
for x=k-1:k+1
for y=l-1:l+1
top=top+(XL(x,y+disparity(k,l),1)-XR(x,y,1))^2+(XL(x,y+disparity(k,l),2)-XR(x,y,2))^2+(XL(x,y+disparity(k,l),3)-XR(x,y,3))^2;
end
end
Ed(k,l)=(1/27)*top;
end
end
%calculates error energy treshold for reliablity of disparity
Toplam=0;
for k=1:m-1
for l=1:nx-1
Toplam=Toplam+Ed(k,l);
end
end
% Error threshold Ve
Ve=Alfa*(Toplam/((m-1)*(nx-1)));
EdReliable=Ed;
disparityReliable=disparityx;
Ne=zeros(m,nx);
for k=1:m-1
for l=1:nx-1
if Ed(k,l)>Ve
% sets unreliable disparity to zero
disparityReliable(k,l)=0;
EdReliable(k,l)=0;
Ne(k,l)=1; % indicates no-estimated state
end
end
end
% calculating reliablities both raw disparity and filtered disparity
TopE=0;
TopER=0;
Sd=0;
for k=1:m-1
for l=1:nx-1
TopE=TopE+Ed(k,l);
if Ne(k,l)==0
TopER=TopER+EdReliable(k,l);
Sd=Sd+1;
end
end
end
ReliablityE=((nx-1)*(m-1))/(TopE);
ReliablityER=(Sd)/(TopER);
% median filtering for repairment of occulations
%disparityF=IterativeAveragingFilter(disparity,5,[4 4]);
disparityF=medfilt2(disparityReliable,[5 5]);
for k=1:m-1
for l=1:nx-1
% Zero disparity produce zero dept
if disparityF(k,l)<5;
DepthMap(k,l)=0;
else
DepthMap(k,l)=foc*(T/disparityF(k,l));
end
end
end
fprintf ('******** Reliablity Report ********** \n')
fprintf ('Reliablity of the disparity map: %f \n',ReliablityE)
fprintf ('Reliablity of the disparity map filtered: %f \n',ReliablityER)
fprintf ('******** Algoritm Speed Report ********** \n')
fprintf ('Time Spend for calculation: %f \n',toc)
figure(1)
imagesc(disparityx);colorbar;
colormap('gray')
title('Disparity Map')
figure(2)
colormap('gray')
imagesc(disparityReliable);colorbar;
title('Disparity Map with Reliable Disparities')
figure(3)
colormap('gray')
imagesc(disparityF);colorbar;
title('Median Filtered Disparity Map with Reliable Disparities')
figure(4)
colormap('gray')
imagesc(DepthMap);colorbar;
title('Depth Map from Disparity Map with Reliable Disparities [cm]')
figure(5)
colormap('gray')
imagesc(log10(Ed));colorbar;
title('Dispatiy Map Error Energy')
figure(6)
imagesc(XR./255)
title('Right Camera Color Image')
figure(7)
imagesc(XL./255)
title('Left Camera Color Image')
figure(8)
colormap('default')
imagesc(regMapx);colorbar;
title('Point Status Map (0: not procesed, 1:region point, 2:rootpoint, 3:idle')
