measure bow-tie coordinates

Contents

%npic = 1; % set externally
g = pictures_storage(:,:,npic);
im = im2double(g);
%h = fspecial('gaussian',9,2);
%im = imresize(imfilter(img,h),1/scl);
imshow(im);
% [IM2 RECT2] = imcrop;
% disp(RECT2);
% rect(n,:)=floor(RECT2+0.5);
rect2 = rect(npic,:);

Warning: Image is too big to fit on screen; displaying at 67% 

clear g img
h = filters2();
h0 = h(:,:,1);
h1 = h(:,:,2);
h2 = h(:,:,3);
h11 = h(:,:,4);
h22 = h(:,:,5);
h12 = h(:,:,6);

edges

a1 = imfilter(im,h1);
a2 = imfilter(im,h2);
bs = imfilter(im,h12);
bsmax = max(max(max(bs)),-min(min(bs)));

show vertices

dpi = 599.406; % value from ruler2 (with filtering)
dpmm = dpi/25.4;


c1 = a1/sum(sum(h1.^2));
c2 = a2/sum(sum(h2.^2));
c3 = bs/sum(sum(h12.^2));

xcen = -c2./c3;
ycen = -c1./c3;
rsq = xcen.^2+ycen.^2;
r = rsq<5;
g = zeros(size(im));
b = abs(bs)>0.2*bsmax;
imshow(cat(3,r,g,b));

Warning: Image is too big to fit on screen; displaying at 67% 

mask = and(r,b);
imshow(mask);

Warning: Image is too big to fit on screen; displaying at 67% 

mask2 = zeros(size(im));
idx = rect2(2)-1+(1:rect2(4));
idy = rect2(1)-1+(1:rect2(3));
mask2(idx,idy)=1;
mask = mask.*mask2;
xcen = xcen.*mask2;
ycen = ycen.*mask2;

calculate vertices

sz = size(im);
xloc = ones(sz(1),1)*(1:sz(2));
yloc = (1:sz(1))'*ones(1,sz(2));
idx = find(mask(:)>0);
xcen=xcen(:);
xloc=xloc(:);
xpt = xloc(idx)+xcen(idx);
ycen=ycen(:);
yloc=yloc(:);
ypt = yloc(idx)+ycen(idx);
plot(xpt,ypt,'o');

sort vertices

k = 0;
xw = xpt;
yw = ypt;
clear xc yc
while ~isempty(xw)
    test = (xw-xw(1)).^2+(yw-yw(1)).^2;
    [tsort idx] = sort(test);
    xw = xw(idx);
    yw = yw(idx);
    idx = find(tsort<64);
    k = k + 1;
    xc(k) = mean(xw(idx));
    yc(k) = mean(yw(idx));
    idx = find(tsort>64);
%     k
%     idx'
    xw = xw(idx);
    yw = yw(idx);
end
plot(xc,yc,'o');

show results (on image)

imshow(im);
hold on
plot(xc,yc,'x','LineWidth',2,'MarkerSize',10);
hold off

Warning: Image is too big to fit on screen; displaying at 67% 

sort points

[tsort idx] = sort(xc);
pts = zeros(3,3,2);
pts(:,:,1) = reshape(tsort,3,3);
pts(:,:,2) = reshape(yc(idx),3,3);
for col=1:3
    [pts(:,col,2) idx] = sort(pts(:,col,2));
    pts(:,col,1) = pts(idx,col,1);
end

widths

width = diff(pts(:,:,1)')';
ydiff = diff(pts(:,:,2)')';
fprintf('%12s\t %12s\t %12s\t %12s\n','row','width 1','width 2','row angle');
fprintf('%12s\t %12s\t %12s\t %12s\n','index','mm','mm','degrees');
for n=1:3
    c = polyfit(pts(n,:,1),pts(n,:,2),1);
    fprintf('%12g\t %12g\t %12g\t %12g\n',floor(pts(n,1,2)),width(n,1),width(n,2),atan(c(1))*180/pi);
end
fprintf('\n\n');

fprintf('mean width %g pixels, std dev %g pixels\n\n\n',mean(width(:)),std(width(:)));

         row	      width 1	      width 2	    row angle
       index	           mm	           mm	      degrees
         362	      56.8551	      56.4236	    0.0971199
         410	      56.8455	       56.486	   -0.0201632
         458	      56.9455	      56.4674	    -0.122343


mean width 56.6705 pixels, std dev 0.235192 pixels

heights

height = diff(pts(:,:,2));
xdiff = diff(pts(:,:,1));
fprintf('%12s\t %12s\t %12s\t %12s\n','col','height 1','height 2','col angle');
fprintf('%12s\t %12s\t %12s\t %12s\n','index','mm','mm','degrees');
for n=1:3
    c = polyfit(pts(:,n,2),pts(:,n,1),1);
    fprintf('%12g\t %12g\t %12g\t %12g\n',floor(pts(1,n,1)),height(1,n),height(2,n),atan(c(1))*180/pi);
end
fprintf('\n\n');


fprintf('mean height %g pixels, std dev %g pixels\n\n\n',mean(height(:)),std(height(:)));

         col	     height 1	     height 2	    col angle
       index	           mm	           mm	      degrees
         916	      47.8698	      47.8062	     0.158407
         973	       47.896	       47.574	     0.212968
        1029	      47.6376	      47.6043	     0.239839


mean height 47.7313 pixels, std dev 0.142525 pixels

center position

fprintf('center %g %g\n\n\n',pts(2,2,1:2));

center 973.686 410.805

show results (on image)

imshow(im);
hold on
plot(xc,yc,'x','LineWidth',2,'MarkerSize',10);
for k=1:3
    for m=1:3
        str = sprintf('%d, %d',k,m);
        text(pts(k,m,1)+5,pts(k,m,2)+5,str,'color','y');
    end
end
hold off

Published with MATLAB® 7.9