forked from SeyedAmirTafrishi/LCS_Filter
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fast9.m
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fast9.m
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%FAST9. perform an FAST corner detection from your FAST-ER generated tree
% [corners, scores] = FAST9.(image, threshold) performs the detection on the image
% and returns the X coordinates in corners(:,1), the Y coordinares in corners(:,2) and
% optionally, the scores in scores(:). The score is computed using binary search over
% all possible thresholds.
%
% [corners, scores] = FAST9.(image, threshold, nonmax) performs the corner
% detection and nonmaximal suppression if nonmax is not zero.
%
% If you use this in published work, please cite:
% Faster and better: A machine learning approach to corner detection, E. Rosten, R. Porter and T. Drummond, PAMI (to appear) 2008
% Machine learning for high-speed corner detection, E. Rosten and T. Drummond, ECCV 2006
% The Bibtex entries are:
%
% @inproceedings{rosten_2006_machine,
% title = "Machine learning for high-speed corner detection",
% author = "Edward Rosten and Tom Drummond",
% year = "2006",
% month = "May",
% booktitle = "European Conference on Computer Vision (to appear)",
% notes = "Poster presentation",
% url = "http://mi.eng.cam.ac.uk/~er258/work/rosten_2006_machine.pdf"
% }
%
% @article{rosten_2008_faster,
% title = "Faster and better: A machine learning approach to corner detection",
% author = "Edward Rosten and Reid Porter and Tom Drummond",
% year = "2008",
% month = "October",
% journal = "IEEE Transactions on Pattern Analysis and Machine Intelligence (to appear)",
% eprint = "arXiv:0810.2434 [cs.CV]",
% url = "http://lanl.arXiv.org/pdf/0810.2434"
% }
function [ corners scores ] = fast9(image, threshold, do_nonmax)
corners = zeros(1024, 2);
num_corners=0;
for y=4:size(image,1)-4
for x=4:size(image,2)-4
cb = image(y, x) + threshold;
c_b = image(y, x) - threshold;
if image(y+3,x+0) > cb
if image(y+3,x+1) > cb
if image(y+2,x+2) > cb
if image(y+1,x+3) > cb
if image(y+0,x+3) > cb
if image(y+-1,x+3) > cb
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
else
if image(y+3,x+-1) > cb
else
continue
end
end
elseif image(y+-3,x+1) < c_b
if image(y+2,x+-2) > cb
if image(y+3,x+-1) > cb
else
continue
end
elseif image(y+2,x+-2) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+-1,x+-3) < c_b
if image(y+0,x+-3) < c_b
if image(y+1,x+-3) < c_b
if image(y+3,x+-1) < c_b
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
if image(y+2,x+-2) > cb
if image(y+3,x+-1) > cb
else
continue
end
else
continue
end
end
elseif image(y+-2,x+2) < c_b
if image(y+3,x+-1) > cb
if image(y+1,x+-3) > cb
if image(y+2,x+-2) > cb
else
continue
end
elseif image(y+1,x+-3) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+-1,x+-3) < c_b
if image(y+0,x+-3) < c_b
if image(y+2,x+-2) < c_b
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+-1,x+-3) < c_b
if image(y+0,x+-3) < c_b
if image(y+1,x+-3) < c_b
if image(y+2,x+-2) < c_b
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
if image(y+1,x+-3) > cb
if image(y+2,x+-2) > cb
if image(y+3,x+-1) > cb
else
continue
end
else
continue
end
elseif image(y+1,x+-3) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+-1,x+-3) < c_b
if image(y+0,x+-3) < c_b
if image(y+2,x+-2) < c_b
if image(y+3,x+-1) < c_b
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
elseif image(y+-1,x+3) < c_b
if image(y+2,x+-2) > cb
if image(y+0,x+-3) > cb
if image(y+1,x+-3) > cb
if image(y+3,x+-1) > cb
else
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
if image(y+-2,x+-2) > cb
if image(y+-1,x+-3) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
continue
end
elseif image(y+0,x+-3) < c_b
if image(y+-2,x+2) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+-1,x+-3) < c_b
if image(y+1,x+-3) < c_b
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
elseif image(y+2,x+-2) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+-1,x+-3) < c_b
if image(y+0,x+-3) < c_b
if image(y+1,x+-3) < c_b
if image(y+-2,x+2) < c_b
else
if image(y+3,x+-1) < c_b
else
continue
end
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
if image(y+-2,x+2) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+-1,x+-3) < c_b
if image(y+0,x+-3) < c_b
if image(y+1,x+-3) < c_b
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
if image(y+0,x+-3) > cb
if image(y+1,x+-3) > cb
if image(y+2,x+-2) > cb
if image(y+3,x+-1) > cb
else
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
if image(y+-2,x+-2) > cb
if image(y+-1,x+-3) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
continue
end
else
continue
end
elseif image(y+0,x+-3) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+-1,x+-3) < c_b
if image(y+1,x+-3) < c_b
if image(y+2,x+-2) < c_b
if image(y+-2,x+2) < c_b
else
if image(y+3,x+-1) < c_b
else
continue
end
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
elseif image(y+0,x+3) < c_b
if image(y+1,x+-3) > cb
if image(y+-1,x+-3) > cb
if image(y+0,x+-3) > cb
if image(y+2,x+-2) > cb
if image(y+3,x+-1) > cb
else
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
if image(y+-2,x+-2) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
if image(y+-1,x+3) > cb
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
if image(y+-2,x+-2) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
continue
end
elseif image(y+-1,x+-3) < c_b
if image(y+-1,x+3) < c_b
if image(y+-2,x+2) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+0,x+-3) < c_b
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
elseif image(y+1,x+-3) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+-1,x+-3) < c_b
if image(y+0,x+-3) < c_b
if image(y+-2,x+2) < c_b
if image(y+-1,x+3) < c_b
else
if image(y+2,x+-2) < c_b
else
continue
end
end
else
if image(y+2,x+-2) < c_b
if image(y+3,x+-1) < c_b
else
continue
end
else
continue
end
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
if image(y+-1,x+3) < c_b
if image(y+-2,x+2) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+-1,x+-3) < c_b
if image(y+0,x+-3) < c_b
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
if image(y+-1,x+-3) > cb
if image(y+0,x+-3) > cb
if image(y+1,x+-3) > cb
if image(y+2,x+-2) > cb
if image(y+3,x+-1) > cb
else
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
if image(y+-2,x+-2) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
if image(y+-1,x+3) > cb
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
if image(y+-2,x+-2) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
continue
end
else
continue
end
elseif image(y+-1,x+-3) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-2,x+-2) < c_b
if image(y+0,x+-3) < c_b
if image(y+1,x+-3) < c_b
if image(y+-2,x+2) < c_b
if image(y+-1,x+3) < c_b
else
if image(y+2,x+-2) < c_b
else
continue
end
end
else
if image(y+2,x+-2) < c_b
if image(y+3,x+-1) < c_b
else
continue
end
else
continue
end
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
elseif image(y+1,x+3) < c_b
if image(y+-2,x+-2) > cb
if image(y+-1,x+-3) > cb
if image(y+0,x+-3) > cb
if image(y+1,x+-3) > cb
if image(y+2,x+-2) > cb
if image(y+3,x+-1) > cb
else
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
if image(y+-1,x+3) > cb
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
if image(y+0,x+3) > cb
if image(y+-1,x+3) > cb
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
continue
end
else
continue
end
elseif image(y+-2,x+-2) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-1,x+-3) < c_b
if image(y+-2,x+2) < c_b
if image(y+-1,x+3) < c_b
if image(y+0,x+3) < c_b
else
if image(y+0,x+-3) < c_b
if image(y+1,x+-3) < c_b
else
continue
end
else
continue
end
end
else
if image(y+0,x+-3) < c_b
if image(y+1,x+-3) < c_b
if image(y+2,x+-2) < c_b
else
continue
end
else
continue
end
else
continue
end
end
else
if image(y+0,x+-3) < c_b
if image(y+1,x+-3) < c_b
if image(y+2,x+-2) < c_b
if image(y+3,x+-1) < c_b
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
if image(y+-2,x+-2) > cb
if image(y+-1,x+-3) > cb
if image(y+0,x+-3) > cb
if image(y+1,x+-3) > cb
if image(y+2,x+-2) > cb
if image(y+3,x+-1) > cb
else
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
if image(y+-1,x+3) > cb
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
if image(y+0,x+3) > cb
if image(y+-1,x+3) > cb
if image(y+-2,x+2) > cb
if image(y+-3,x+1) > cb
if image(y+-3,x+0) > cb
if image(y+-3,x+-1) > cb
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
else
continue
end
else
continue
end
elseif image(y+-2,x+-2) < c_b
if image(y+-3,x+1) < c_b
if image(y+-3,x+0) < c_b
if image(y+-3,x+-1) < c_b
if image(y+-1,x+-3) < c_b
if image(y+0,x+-3) < c_b
if image(y+-2,x+2) < c_b
if image(y+-1,x+3) < c_b
if image(y+0,x+3) < c_b
else
if image(y+1,x+-3) < c_b
else
continue
end
end
else
if image(y+1,x+-3) < c_b
if image(y+2,x+-2) < c_b
else
continue
end
else
continue
end
end
else
if image(y+1,x+-3) < c_b
if image(y+2,x+-2) < c_b
if image(y+3,x+-1) < c_b
else
continue
end
else
continue
end
else
continue
end
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
else
continue
end
end
elseif image(y+2,x+2) < c_b
if image(y+-3,x+-1) > cb
if image(y+-2,x+-2) > cb
if image(y+-1,x+-3) > cb
if image(y+0,x+-3) > cb
if image(y+1,x+-3) > cb
if image(y+2,x+-2) > cb