1 | function [M, pts] = unoccluded_motion(nframes,npoints,frot,ftrans)
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2 |
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3 | % To generate this, we'll consider a very simple situation in which the motion
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4 | % is constant, and the points are randomly chosen from within a cube.
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5 | % the cube in between 0 and 1 in each dimension, so the image will be
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6 | % roughly of size 1x1.
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7 | % We assume that the key variable is the amount of rotation in depth,
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8 | % so we'll make the in-plane rotation constant so that it adds up to
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9 | % ninety degrees, and the translation constant,
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10 | % in a random direction.
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11 |
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12 | M = [];
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13 | translation_mag = ftrans/(nframes-1);
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14 | ip_rot = (pi/2)/(nframes-1);
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15 | op_rot = (2*pi*frot)/(nframes-1);
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16 |
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17 | pts = rand(4,npoints);
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18 | pts(4,:) = ones(1,npoints);
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19 | % points have x,y,z coordinates, and a 1 in the 4th row for translation.
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20 |
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21 |
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22 | depth_axis = 2*pi*rand(1);
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23 | %depth_axis = 0;
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24 | translation_dir = 2*pi*rand(1);
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25 | translation_vec = translation_mag*[cos(translation_dir), sin(translation_dir),0];
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26 |
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27 | rpts1 = rotate_z_axis(pts,depth_axis);
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28 |
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29 |
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30 | for fnum=0:nframes-1
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31 | rpts2 = rotate_x_axis(rpts1,op_rot*fnum);
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32 | rpts3 = rotate_z_axis(rpts2,-depth_axis);
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33 | rpts4 = rotate_z_axis(rpts3,ip_rot*fnum); |
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34 | rpts5 = translate(rpts4,fnum*translation_vec);
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35 | M = [M',rpts5(1:2,:)']';
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36 | end
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37 |
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