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SURF feature extractor
sf = isurf(im, options) returns a vector of SurfPointFeature objects representing scale and rotationally invariant interest points in the image im.
The SurfPointFeature object has many properties including:
u | horizontal coordinate |
v | vertical coordinate |
strength | feature strength |
descriptor | feature descriptor (64x1 or 128x1) |
sigma | feature scale |
theta | feature orientation [rad] |
'nfeat', N | set the number of features to return (default Inf) |
'thresh', T | set Hessian threshold. Increasing the threshold reduces the number of features computed and reduces computation time. |
'octaves', N | number of octaves to process (default 5) |
'extended' | return 128-element descriptor (default 64) |
'upright' | don't compute rotation invariance |
'suppress', R | set the suppression radius (default 0). Features are not returned if they are within R [pixels] of an earlier (stronger) feature. |
Load the image
im = iread('lena.pgm');
Find the 10 strongest SURF features
sf = isurf(im, 'nfeat', 10);
and overlay them on the original image as blue circles
idisp(im); sf.plot_scale()
"SURF: Speeded Up Robust Features", Herbert Bay, Andreas Ess, Tinne Tuytelaars, Luc Van Gool, Computer Vision and Image Understanding (CVIU), Vol. 110, No. 3, pp. 346--359, 2008
SurfPointFeature, isift, icorner
© 1990-2012 Peter Corke.