% we just downloaded the image 'Library'
% and saved it in the current directory
x = imread('Library.jpg');
size(x)

ans =

   200   300     3

% for every pixel, x encodes the RGB color
image(x)
% to remove all blue from the picture,
% we set the blue color to zero
noblue = x;
noblue(:,:,3) = zeros(size(x,1),size(x,2));
image(noblue)
% to calculate with the colors,
% we have to convert the data type from
% uint (unsigned integers) to double
dx = double(x);
% we going to increase the blue intensity
moreblue = dx;
moreblue(:,:,3) = 1.5*dx(:,:,3);
% to view the image, we must convert
% back to the short uint (short = 1 byte)
y = uint8(moreblue);
figure
image(y)
% Movies
% Animations in MATLAB have the nice
% feature that we can determine the
% camera position
figure
subplot(2,1,1);
membrane
hold on
xlabel('x'); ylabel('y'); zlabel('z');
s = [-0.9  1.0  0.2];
plot3(s(1),s(2),s(3),'r+');
p = [0.5 0.0 1.1];
plot3(p(1),p(2),p(3),'bx');
% the goal is to aim our camera at
% the peak, with coordinates in p
% starting at s
subplot(2,1,2);
membrane;
hold on
set(gca,'CameraPosition',s);
set(gca,'CameraTarget',p);
set(gca,'Projection','Perspective');
figure
membrane
hold on
set(gca,'CameraPosition',s);
set(gca,'CameraTarget',p);
set(gca,'Projection','Perspective');
hold off
membrane
set(gca,'CameraPosition',s);
topeak = moviein(100);
topeak(:,1) = getframe;
dt = 0.01;
for i = 2:100
     s(1) = s(1) + dt; s(2) = s(2) + 0.5*dt;
     set(gca,'CameraPosition',s);
     topeak(:,i) = getframe;
end;
figure
movie(topeak)
diary off