how can I rotate the image ?

Hello,

I have this function :

function spin = generate_spin_image(vertex, normal, indVertex, med)
%[vertex, faces] = read_off(namefile);
%med = computeMedianEdge(namefile);
%[normal,normalf] = compute_normal(vertex, faces);

binSize = med;
W = 25;
angleSupport = pi/2;
imageWidth = W*binSize;

p = vertex(indVertex,:);
numVertices = size(vertex,1);
%alpha = zeros(numVertices,1);
%beta = zeros(numVertices,1);
spin = zeros(W,W);
TabAlpha_1 = zeros(1,34817);
TabBeta_1 = zeros(1,34817);

for i=1:numVertices
    x = vertex(i,:);
    if acos(sum(normal(indVertex,:).*normal(i,:))) < angleSupport
        alpha = sqrt(sum((x - p).^2) - (sum(normal(indVertex,:).*(x-p))).^2);
        beta = sum(normal(indVertex,:).*(x-p));

           TabAlpha_1(i) = alpha;  
           TabBeta_1(i) = beta;

          is = floor((imageWidth/2 - beta)/binSize);
          js = floor(alpha/binSize);
          a = alpha/binSize - js;
          b = (imageWidth/2-beta)/binSize - is;
          if is >=1 && is <=(W-1) && js >=1 && js <=(W-1)
              spin(is,js) = spin(is,js) + (1-a)*(1-b);
              spin(is+1,js) = spin(is+1,js) + a*(1-b);
              spin(is, js+1)= spin(is,js+1) + (1-a)*b;
              spin(is+1,js+1) = spin(is+1,js+1) + a*b;
          end
      end
  end
  figure;
  TabBeta_1 = TabBeta_1';
  TabAlpha_1 = TabAlpha_1';
  plot(TabBeta_1, TabAlpha_1, 'ro');

figure;
imagesc(spin');
colormap( flipud(gray) );

In the end I plot the array that contains the projection of the 3D coordinates of a vertex in 2D coordiantes (alpha, beta), and the image spin results from the computation of alpha and beta.

The problem I have is that it gives me this:

It seems to be good but the image (grayscale) is rotated compared to the projection (plot with red points), and I want it to be the same as the plot.

I hop I explained my problem clairly. I would be grateful for any help.

Answer 1

[Image Analyst]

The top (line 1) of an image is at the top while for a plot it's normally at the bottom. Set the 'ydir' property of the plot to be 'reverse' and they'll both go in the same direction.

plot(......
ax = gca;
ax.YDir = 'reverse';

Answer 2

[Nut]

Hi,

I'm not sure but I think that the "view" function could help you:

http://it.mathworks.com/help/matlab/ref/view.html

Alternatively, if you need just a different view, maybe you can solve changing the signs of the coordinates of red points when you plot them.

[jiji hr]

It didn't works becaus if I understood very well, it is for 3D plots, and I have juste a 2D plot.

Any way I found the solution using

imrotate(spinImages.spinIm,180);

And thank you so much for your answer.

[Nut]

Ok, good idea. I thought you need to rotate the red points, not the image. I was misunderstanding, sorry.

Kind regards.