Rotate an object based on regionprops Orientation, MinFeret and MaxFeret angles

How can I rotate an object based on regionprops Orientation, MinFeret and MaxFeret angles?

My aim is that the object and the regionprops based plotted lines will be 0 or 90 degrees.

Thanks.

Code:

    close all;
    clear;
    clc;
    
    I = (insertText(zeros(150,150),[0 0],'B','BoxOpacity',0,'FontSize',70,'TextColor','w'));
    I = imrotate(I,15);
    I = rgb2gray(I);
    figure('Name','Img');
    imshow(I);

    I=flipud(I);
    BW = imbinarize(I);
    [B,L] = bwboundaries(BW,'noholes');
    
    k=1;
    st = regionprops(I,"Centroid","MajorAxisLength","Orientation","MinFeretProperties","MaxFeretProperties");
    b = B{k};
    c = st(k).Centroid;
    yBoundary = b(:,2);
    xBoundary = b(:,1);
    
    cy = c(:,2);
    cx = c(:,1);
    figure('Name','Boundary and lines');
    plot(yBoundary, xBoundary, 'black', 'linewidth', 2);
    hlen = st.MajorAxisLength/2;
    xCentre = st.Centroid(1);
    yCentre = st.Centroid(2);
    cosOrient = cosd(st.Orientation);
    sinOrient = sind(st.Orientation);
    xcoords = xCentre + hlen * [cosOrient -cosOrient];
    ycoords = yCentre + hlen * [-sinOrient sinOrient];
    
    line(xcoords, ycoords, 'Color','red');
    line([st.MaxFeretCoordinates(1),st.MaxFeretCoordinates(2)],[st.MaxFeretCoordinates(3),st.MaxFeretCoordinates(4)],'Color','blue');
    line([st.MinFeretCoordinates(1),st.MinFeretCoordinates(2)],[st.MinFeretCoordinates(3),st.MinFeretCoordinates(4)],'Color','green');

    
    orientationRotImg = imrotate(I,  st.Orientation-90);
    figure('Name','orientationRotImg');
    imshow(orientationRotImg)

    
    MaxFeretAngleRotImg = imrotate(I,  st.MaxFeretAngle-90);
    figure('Name','MaxFeretAngleRotImg');
    imshow(MaxFeretAngleRotImg)

    
    MinFeretAngleRotImg = imrotate(I,  st.MinFeretAngle-90);
    figure('Name','MaxFeretAngleRotImg');
    imshow(MinFeretAngleRotImg)

[Walter Roberson]

Yes? You appear to be doing so already ?

[Asi]

OK. So how do I rotate it to a "B normal position"?

[Walter Roberson]

The min ferret angle and max ferret angle are not typically going to be 90 degrees from each other, so requiring that both be rotated to horizontal or vertical is not typically going to work.

Answer 1

[Walter Roberson]

    close all;
    clear;
    clc;
    
    I = (insertText(zeros(150,150),[0 0],'B','BoxOpacity',0,'FontSize',70,'TextColor','w'));
    I = imrotate(I,15);
    I = rgb2gray(I);
    figure('Name','Img');
    imshow(I);

    I=flipud(I);
    BW = imbinarize(I);
    [B,L] = bwboundaries(BW,'noholes');
    
    k=1;
    st = regionprops(I,"Centroid","MajorAxisLength","Orientation","MinFeretProperties","MaxFeretProperties");

        MinFeretAngleRotImg = imrotate(I,  st.MinFeretAngle);
    figure('Name','MaxFeretAngleRotImg');
    imshow(MinFeretAngleRotImg)

[Asi]

Hi,

Thanks but it seems to me that the B should be flliped.

I tried the code with another letter "A"

I = (insertText(zeros(150,150),[0 0],'A','BoxOpacity',0,'FontSize',70,'TextColor','w'));

and this us the result of MinFeretAngleRotImg = imrotate(I, st.MinFeretAngle);

Any other ideas how to solve it also as a general solution for object (text, geometric shape, etc)?