scanned target calibration (part 2)
Contents
image
clear
close all
rgb = imread('Scan_Pic0003.jpg');
img = im2double(rgb2gray(rgb));
sz = size(img);
img = img(400:sz(1),:);
h = fspecial('gaussian',9,2);
scl=2;
im = imresize(imfilter(img,h),1/scl);
imshow(im);
Warning: Image is too big to fit on screen; displaying at 67%
border = zeros(size(im));
n = 120;
n2 = floor(n/2);
sz = size(im)-n;
border(n2+(1:sz(1)),n2+(1:sz(2)))=1;
clear rgb 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;
dpmm = dpi/25.4;
c1 = a1/sum(sum(h1.^2));
c2 = a2/sum(sum(h2.^2));
c3 = bs/sum(sum(h12.^2)).*border;
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);
sum(sum(mask))
Warning: Image is too big to fit on screen; displaying at 67%
ans =
94
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);
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%
widths
pts(:,:,1) = reshape(xc,3,3);
pts(:,:,2) = reshape(yc,3,3);
pts = sort(pts,1);
width = scl*diff(pts(:,:,1)')'/dpmm;
ydiff = scl*diff(pts(:,:,2)')'/dpmm;
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 mm, std dev %g mm\n',mean(width(:)),std(width(:)));
row width 1 width 2 row angle
index mm mm degrees
222 36.5275 36.5015 -0.357284
580 36.5011 36.5059 -0.343459
938 36.4948 36.5091 -0.27241
mean width 36.5066 mm, std dev 0.0113134 mm
heights
height = scl*diff(pts(:,:,2))/dpmm;
xdiff = scl*diff(pts(:,:,1))/dpmm;
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 mm, std dev %g mm\n',mean(height(:)),std(height(:)));
col height 1 height 2 col angle
index mm mm degrees
282 30.3638 30.3121 0.126876
713 30.3216 30.4 0.095922
1143 30.3816 30.4026 0.102925
mean height 30.3636 mm, std dev 0.0389673 mm