Source code for
vl_demo_sift_edge.m
This file is located in the toolbox/demo folder in VLFeat package.
% VL_DEMO_SIFT_EDGE Demo: SIFT: edge treshold
randn('state',0) ;
rand('state',0) ;
I = zeros(100,500) ;
for i=[10 20 30 40 50 60 70 80 90]
d = round(i/3) ;
I(50-d:50+d,i*5) = 1 ;
end
I = 2*pi*8^2 * vl_imsmooth(I,8) ;
I = single(255 * I) ;
figure(1) ; clf ;
imagesc(I) ; colormap gray ;
axis equal ; axis off ; axis tight ;
hold on ;
vl_demo_print('sift_edge_0') ;
ter=[3.5 5 7.5 10] ;
for te=ter
f = vl_sift(I, ...
'PeakThresh', 0, ...
'EdgeThresh', te, ...
'FirstOctave', -1 ) ;
h1 = vl_plotframe(f) ;
set(h1,'color','k','linewidth',3) ;
h2 = vl_plotframe(f) ;
set(h2,'color','y','linewidth',2) ;
vl_demo_print(sprintf('sift_edge_%d', find(te==ter))) ;
delete(h1) ;
delete(h2) ;
end