MATLAB CODE:
%% Read in the images you want to do a dlt on
% cd(‘/Users/Tadd/Documents/0_Current Projects/Courses/BYU 363 Fall2010/Quizes’)
IL = imread(‘DLT_Quiz_L.jpg’);
IR = imread(‘DLT_Quiz_R.jpg’);
% You must know the actual location of the six points in space before you
% begin so insert them here.
x = [0 0 0.5 0.5 0 0 0.5];
y = [0.5 0 0.5 0 0.5 0 0 ];
z = [0.5 0.5 0.5 0.5 0 0 0 ];
xyz = [x;y;z];
%% Get the 7 points of interest
figure(10),clf
imshow(imread(‘DLT_Quiz_ORDER.jpg’))
figure(1),clf
imshow(IL)
title(‘Left image: Pick 7 points of interest corresponding to the points in x,y,z’)
[uL,vL] = ginput(7);
hold on
plot(uL,vL,’rx’)
text(uL(1),vL(1),’1′)
text(uL(2),vL(2),’2′)
text(uL(3),vL(3),’3′)
text(uL(4),vL(4),’4′)
text(uL(5),vL(5),’5′)
text(uL(6),vL(6),’6′)
text(uL(7),vL(7),’7′)
figure(2),clf
imshow(IR)
title(‘Right image: Pick 7 points of interest corresponding to the points in x,y,z’)
[uR,vR] = ginput(7);
hold on
plot(uR,vR,’rx’)
text(uR(1),vR(1),’1′)
text(uR(2),vR(2),’2′)
text(uR(3),vR(3),’3′)
text(uR(4),vR(4),’4′)
text(uR(5),vR(5),’5′)
text(uR(6),vR(6),’6′)
text(uR(7),vR(7),’7′)
%% Determine the L matrix
% Make the parts of the FL matrix
tu = repmat([1 0 0 0 0],7,1);
tv = repmat([0 0 0 0],7,1);
tv2 = repmat([1],7,1);
XL = horzcat(xyz’,tu,[-uL.*xyz(1,:)’],[-uL.*xyz(2,:)’],[-uL.*xyz(3,:)’]);
YL = horzcat(tv,xyz’,tv2,[-vL.*xyz(1,:)’],[-vL.*xyz(2,:)’],[-vL.*xyz(3,:)’]);
XR = horzcat(xyz’,tu,[-uR.*xyz(1,:)’],[-uR.*xyz(2,:)’],[-uR.*xyz(3,:)’]);
YR = horzcat(tv,xyz’,tv2,[-vR.*xyz(1,:)’],[-vR.*xyz(2,:)’],[-vR.*xyz(3,:)’]);
FL = vertcat(XL(1,:),YL(1,:));
gL = vertcat(uL(1,:),vL(1,:));
FR = vertcat(XL(1,:),YR(1,:));
gR = vertcat(uL(1,:),vR(1,:));
for i = 2:length(uL)
gL = vertcat(gL,uL(i),vL(i)); % Fill in the gL matrix
FL = vertcat(FL,XL(i,:),YL(i,:));% Fill in the FL matrix
gR = vertcat(gR,uR(i),vR(i)); % Fill in the gR matrix
FR = vertcat(FR,XR(i,:),YR(i,:));% Fill in the FR matrix
end
% Matrix manipulation using the Morse-Penrose pseudo-inverse method
L = (FL’*FL)^-1*FL’*gL;
R = (FR’*FR)^-1*FR’*gR;
disp(L)
disp(R)
%% Now find another point on the block.
figure(1),clf
imshow(IL)
title(‘Pick a point you want to know the distance from origin to’)
hold on
plot(uL,vL,’rx’)
text(uL(1),vL(1),’1′)
text(uL(2),vL(2),’2′)
text(uL(3),vL(3),’3′)
text(uL(4),vL(4),’4′)
text(uL(5),vL(5),’5′)
text(uL(6),vL(6),’6′)
text(uL(7),vL(7),’7′)
[UL,VL] = ginput(1);
plot(UL,VL,’bo’)
figure(2),clf
imshow(IR)
title(‘Pick a point you want to know the distance from origin to’)
hold on
plot(uR,vR,’rx’)
text(uR(1),vR(1),’1′)
text(uR(2),vR(2),’2′)
text(uR(3),vR(3),’3′)
text(uR(4),vR(4),’4′)
text(uR(5),vR(5),’5′)
text(uR(6),vR(6),’6′)
text(uR(7),vR(7),’7′)
[ULR,VLR] = ginput(1);
plot(UR,VR,’bo’)
Q = [L(1)-L(9)*UL, L(2)-L(10)*UL, L(3)-L(11)*UL;…
L(5)-L(9)*VL, L(6)-L(10)*VL, L(7)-L(11)*VL;…
R(1)-R(9)*UR, R(2)-R(10)*UR, R(3)-R(11)*UR;…
R(5)-R(9)*VR, R(6)-R(10)*VR, R(7)-R(11)*VR];
q = [UL-L(4); VL-L(8); UR-R(4); VR-R(8)];
a_xyz = (Q’*Q)^-1*Q’*q;
figure(2)
text(UR,VR,[num2str(a_xyz(1),2),’,’,num2str(a_xyz(2),2),’,’,num2str(a_xyz(3),2)])
disp(a_xyz)
