MATLAB: Rotate binary object around its centroid

binary imagebinary objectcentroidImage Processing Toolboxrotation

Hi, I have a small problem. I am trying to rotate image in 2D but around custom axis. I mean, I have a centroid of binary object and now I want to rotate it but around that centroid point. Can somebody help me?

Best Answer

Try using imtranslate() or circshift() to shift the centroid to the middle, then call imrotate(), then shift back to the original location. Otherwise, just use the rotation matrix (see Wikipedia).

Related Solutions

MATLAB: Rotate Normal Around Tangent

I'm assuming you're choosing the radius, R, of this circle. Then if T and N are the tangent and normal vectors at point P on the curve (all in column vector form):

n=1000;
theta=linspace(0,2*pi,n+1); 
  theta(end)=[];
refcircle = [R*cos(theta);R*sin(theta);zeros(1,n);ones(1,n)] ;
T=T/norm(T);
N=N/norm(N);
E=cross(N,T);
A=[0 0 0; R 0 0; 0 R 0].';
B=[P,P+R*N,P+R*E];
params=absor(A,B);  %get this function from FEX
C = params.M*refcircle; %circle points at 3D curve
plot3(C(1,:), C(2,:), C(3,:)) %plot the circle

The above uses ABSOR, available here

http://www.mathworks.com/matlabcentral/fileexchange/26186-absolute-orientation-horns-method

MATLAB: How to get Pixels on two circles with radii R and R’ for an image with angles 0, 45, 90, 135, 180, 225, 270, 315, 360.Extented local Binary Pattern(ELBP)

Well, you know the formulas, don't you

x = xCenter + r * cosd(theta)
y = yCenter + r * sind(theta)

and so on. So where are you having trouble? Just round it to get the columns and rows

column = round(x);
row = round(y);
pixelValue = yourImage(row, column);

I'm attaching my LBP demo.

Best Answer

Related Solutions

MATLAB: Rotate Normal Around Tangent

MATLAB: How to get Pixels on two circles with radii R and R’ for an image with angles 0, 45, 90, 135, 180, 225, 270, 315, 360.Extented local Binary Pattern(ELBP)

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