% Demonstration of feature matching via simple correlation, and then using % RANSAC to estimate the fundamental matrix and at the same time identify % (mostly) inlying matches % % Usage: testfund - Demonstrates fundamental matrix calculation % on two default images % testfund(im1,im2) - Computes fundamental matrix on two supplied images % % Edit code as necessary to tweak parameters % Copyright (c) 2004-2005 Peter Kovesi % School of Computer Science & Software Engineering % The University of Western Australia % http://www.csse.uwa.edu.au/ % % Permission is hereby granted, free of charge, to any person obtaining a copy % of this software and associated documentation files (the "Software"), to deal % in the Software without restriction, subject to the following conditions: % % The above copyright notice and this permission notice shall be included in % all copies or substantial portions of the Software. % % The Software is provided "as is", without warranty of any kind. % February 2004 % August 2005 Octave compatibility function [Ftrans,correlations]=testfund(im1,im2) if nargin == 0 im1 = imread('im02.jpg'); im2 = imread('im03.jpg'); end correlations = []; v = version; Octave=0;% Crude Octave test thresh = 500; % Harris corner threshold nonmaxrad = 3; % Non-maximal suppression radius dmax = 100; % Maximum search distance for matching w = 11; % Window size for correlation matching % Find Harris corners in image1 and image2 [cim1, r1, c1] = harris(im1, 1, thresh, 3); clear cim1; show(im1,1), hold on, plot(c1,r1,'r+'); [cim2, r2, c2] = harris(im2, 1, thresh, 3); clear cim2; show(im2,2), hold on, plot(c2,r2,'r+'); drawnow correlation = 0; % Change this between 1 or 0 to switch between the two % matching functions below if correlation % Use normalised correlation matching [m1,m2] = matchbycorrelation(im1, [r1';c1'], im2, [r2';c2'], w, dmax); else % Use monogenic phase matching nscale = 1; minWaveLength = 10; mult = 4; sigmaOnf = .2; [m1,m2] = matchbymonogenicphase(im1, [r1';c1'], im2, [r2';c2'], w, dmax,... nscale, minWaveLength, mult, sigmaOnf); end % Display putative matches show(im1,3), set(3,'name','Putative matches') if Octave, figure(1); title('Putative matches'), axis('equal'), end for n = 1:length(m1); line([m1(2,n) m2(2,n)], [m1(1,n) m2(1,n)]) end % Assemble homogeneous feature coordinates for fitting of the % fundamental matrix, note that [x,y] corresponds to [col, row] x1 = [m1(2,:); m1(1,:); ones(1,length(m1))]; x2 = [m2(2,:); m2(1,:); ones(1,length(m1))]; t = .002; % Distance threshold for deciding outliers % Change the commenting on the lines below to switch between the use % of 7 or 8 point fundamental matrix solutions, or affine fundamental % matrix solution. % [F, inliers] = ransacfitfundmatrix7(x1, x2, t, 1); [F, inliers] = ransacfitfundmatrix(x1, x2, t, 1); % [F, inliers] = ransacfitaffinefund(x1, x2, t, 1); fprintf('Number of inliers was %d (%d%%) \n', ... length(inliers),round(100*length(inliers)/length(m1))) [Ftrans, transinliers] = ransacfittransfundmatrix(x1, x2, t, 1); correlations = [correlations;[m1(:,transinliers)',m2(:,transinliers)']]; [U,S,V]=svd(Ftrans); epipole=[V(2,3)/V(3,3);V(1,3)/V(3,3)] fprintf('Number of inliers was %d (%d%%) \n', ... length(inliers),round(100*length(transinliers)/length(m1))) fprintf('Number of putative matches was %d \n', length(m1)) % Display both images overlayed with inlying matched feature points if Octave figure(4); title('Inlying matches'), axis('equal'), else show(im1,4), set(4,'name','Inlying matches'), hold on end plot(m1(2,inliers),m1(1,inliers),'c+'); % plot(m2(2,inliers),m2(1,inliers),'g+'); for n = inliers line([m1(2,n) m2(2,n)], [m1(1,n) m2(1,n)],'color',[0 0 1]) end show(im2,5), set(5,'name','Inlying matches'), hold on % plot(m1(2,inliers),m1(1,inliers),'c+'); plot(m2(2,inliers),m2(1,inliers),'g+'); for n = inliers line([m1(2,n) m2(2,n)], [m1(1,n) m2(1,n)],'color',[0 0 1]) end if Octave figure(4); title('Inlying matches'), axis('equal'), else show(im1,6), set(6,'name','Translational Inlying matches'), hold on end plot(m1(2,transinliers),m1(1,transinliers),'c+'); % plot(m2(2,inliers),m2(1,inliers),'g+'); for n = transinliers line([m1(2,n) m2(2,n)], [m1(1,n) m2(1,n)],'color',[0 0 1]) end show(im2,7), set(7,'name','translational Inlying matches'), hold on % plot(m1(2,inliers),m1(1,inliers),'c+'); plot(m2(2,transinliers),m2(1,transinliers),'g+'); for n = transinliers line([m1(2,n) m2(2,n)], [m1(1,n) m2(1,n)],'color',[0 0 1]) end % determine which picture is closer to the epipole p1 = [r1(transinliers)-epipole(1),c1(transinliers)-epipole(2)]'; p2 = [r2(transinliers)-epipole(1),c2(transinliers)-epipole(2)]'; dist1 = sum((sum(p1.^2)).^.5); dist2 = sum((sum(p2.^2)).^.5); cImage = (dist1>dist2)+1; DualMatches=guide([r1,c1]', [r2,c2]', epipole, 17, .85, .2,150,cImage,im1,im2 ); % correlations = [correlations;[r1(DualMatches(:,1)),c1(DualMatches(:,1)),r2(DualMatches(:,2)),c2(DualMatches(:,2))]]; correlations = [r1(DualMatches(:,1)),c1(DualMatches(:,1)),r2(DualMatches(:,2)),c2(DualMatches(:,2))]; fprintf('Number of guided matches was %d \n', size(DualMatches,1)) show(im1,9), set(9,'name','Dual matches'), hold on plot(c1(DualMatches(:,1)),r1(DualMatches(:,1)),'g+'); % plot(c2(DualMatches(:,2)),r2(DualMatches(:,2)),'g+'); %plot(epipole(2),epipole(1),'r*'); for n = 1:1:size(DualMatches,1) line([c1(DualMatches(n,1)) c2(DualMatches(n,2))], [r1(DualMatches(n,1)) r2(DualMatches(n,2))],'color',[0 0 1]) end show(im2,8), set(8,'name','Dual matches'), hold on % plot(c1(DualMatches(:,1)),r1(DualMatches(:,1)),'c+'); plot(c2(DualMatches(:,2)),r2(DualMatches(:,2)),'g+'); %plot(epipole(2),epipole(1),'r*'); for n = 1:1:size(DualMatches,1) line([c1(DualMatches(n,1)) c2(DualMatches(n,2))], [r1(DualMatches(n,1)) r2(DualMatches(n,2))],'color',[0 0 1]) end show(im1,11), set(11,'name','All matches'), hold on plot(correlations(:,2),correlations(:,1),'g+'); % plot(c2(DualMatches(:,2)),r2(DualMatches(:,2)),'g+'); %plot(epipole(2),epipole(1),'r*'); for n = 1:1:size(correlations,1) line([correlations(n,2) correlations(n,4)], [correlations(n,1) correlations(n,3)],'color',[0 0 1]) end show(im2,10), set(10,'name','All matches'), hold on % plot(c1(DualMatches(:,1)),r1(DualMatches(:,1)),'c+'); plot(correlations(:,4),correlations(:,3),'g+'); %plot(epipole(2),epipole(1),'r*'); for n = 1:1:size(correlations,1) line([correlations(n,2) correlations(n,4)], [correlations(n,1) correlations(n,3)],'color',[0 0 1]) end n