Description

Source Code:

pm0 = [776.649963 -298.408539 -32.048386 993.1581875;132.852554 120.885834 -759.210876 1982.174000;0.744869 0.662592 -0.078377 4.629312012]; pm1 = [431.503540 586.251892 -137.094040 1982.053375;23.799522 1.964373 657.832764 1725.253500;-0.321776 0.869462 -0.374826 5.538025391]; pm2 = [-153.607925 722.067139 -127.204468 2182.4950;141.564346 74.195686 637.070984 1551.185125;-0.769772 0.354474 -0.530847 4.737782227]; pm3 = [-823.909119 55.557896 -82.577644 2498.20825;-31.429972 42.725830 777.534546 2083.363250;-0.484634 -0.807611 -0.335998 4.934550781]; pm4 = [-715.434998 -351.073730 -147.460815 1978.534875;29.429260 -2.156084 -779.121704 2028.892750;0.030776 -0.941587 -0.335361 4.141203125]; pm5 = [-417.221649 -700.318726 -27.361042 1599.565000;111.925537 –
169.101776 -752.020142 1982.983750;0.542421 -0.837170 -0.070180
3.929336426];
pm6 = [94.934860 -668.213623 -331.895508 769.8633125;-549.403137 58.174614 -342.555359 1286.971000;0.196630 -0.136065 -0.970991 3.574729736];
pm7 = [452.159027 -658.943909 -279.703522 883.495000;-262.442566 1.231108 -751.532349 1884.149625;0.776201 0.215114 -0.592653 4.235517090]; s0 = imread(‘silh_cam00_00023_0000008550.pbm’); s1 = imread(‘silh_cam01_00023_0000008550.pbm’); s2 = imread(‘silh_cam02_00023_0000008550.pbm’); s3 = imread(‘silh_cam03_00023_0000008550.pbm’); s4 = imread(‘silh_cam04_00023_0000008550.pbm’); s5 = imread(‘silh_cam05_00023_0000008550.pbm’); s6 = imread(‘silh_cam06_00023_0000008550.pbm’); s7 = imread(‘silh_cam07_00023_0000008550.pbm’); i0 = imread(‘cam00_00023_0000008550.png’); i1 = imread(‘cam01_00023_0000008550.png’); i2 = imread(‘cam02_00023_0000008550.png’); i3 = imread(‘cam03_00023_0000008550.png’); i4 = imread(‘cam04_00023_0000008550.png’); i5 = imread(‘cam05_00023_0000008550.png’); i6 = imread(‘cam06_00023_0000008550.png’); i7 = imread(‘cam07_00023_0000008550.png’);
pm = zeros(3,4,8); s = zeros(582, 780, 8); im = zeros(582, 780, 3, 8);
pm(:,:,1) = pm0; pm(:,:,2) = pm1; pm(:,:,3) = pm2; pm(:,:,4) = pm3; pm(:,:,5) = pm4; pm(:,:,6) = pm5; pm(:,:,7) = pm6; pm(:,:,8) = pm7; s(:,:,1) = s0; s(:,:,2) = s1; s(:,:,3) = s2; s(:,:,4) = s3; s(:,:,5) = s4; s(:,:,6) = s5; s(:,:,7) = s6; s(:,:,8) = s7;
im(:,:,:,1) = i0; im(:,:,:,2) = i1; im(:,:,:,3) = i2; im(:,:,:,4) = i3; im(:,:,:,5) = i4; im(:,:,:,6) = i5; im(:,:,:,7) = i6; im(:,:,:,8) = i7;
x_grid = 5; y_grid = 6; z_grid = 2.5;
vol = x_grid * y_grid * z_grid; no_voxs = 10000000; vox_s = nthroot(vol/no_voxs,3); true_no_voxs = 0; total_no_voxs = 0; vox_mat = []; sur_vox_mat = []; color_mat = []; fl = 0; prev_vec = [];
for x = -x_grid/2:vox_s:x_grid/2 for y = -y_grid/2:vox_s:y_grid/2 for z = 0:vox_s:z_grid dec_v = [0 0 0 0 0 0 0 0]; total_no_voxs = total_no_voxs + 1; w_col = [x y z 1.0].’; for i = 1:8
uv_cor = pm(:,:,i)*w_col; uv_cor = round(uv_cor/uv_cor(3));
if (1<=uv_cor(1)) && (uv_cor(1)<=780) && (1<=uv_cor(2)) &&
(uv_cor(2)<=582)
dec_v(i) = s(uv_cor(2),uv_cor(1),i); end end
if all(dec_v) == 1
true_no_voxs = true_no_voxs + 1; vox_mat = [vox_mat;[x y z]]; r = im(uv_cor(2), uv_cor(1), 1, 8); g = im(uv_cor(2), uv_cor(1), 2, 8); b = im(uv_cor(2), uv_cor(1), 3, 8); color_mat = [color_mat;[r g b]];

% The code below is for detecting surface voxels
% and discarding non-surface voxels. if fl == 0
sur_vox_mat = [sur_vox_mat;[x y z]]; fl = fl+1; prev_vec = [x y z]; continue; end
if (prev_vec(1)==x) && (prev_vec(2)==y) fl = fl+1; else if fl > 1
sur_vox_mat = [sur_vox_mat;prev_vec;[x y z]]; f1=1; else
sur_vox_mat = [sur_vox_mat;[x y z]]; f1=1; end end if fl > 0
prev_vec = [x y z]; end end end
end end vox_mat_ptc = pointCloud(vox_mat); vox_mat_ptc.Color = uint8(color_mat);
pcwrite(vox_mat_ptc,’dancer_full_colored_2′,’PLYFormat’,’ascii’); full_mod = pcread(‘dancer_full_colored_2.ply’); pcshow(full_mod);

%The code below is for creating a PLY file for the point cloud %created by using only surface voxels.

sur_vox_mat_ptc = pointCloud(sur_vox_mat);
pcwrite(sur_vox_mat_ptc,’dancer_surf_2′,’PLYFormat’,’ascii’); surf_mod = pcread(‘dancer_surf_2.ply’); pcshow(surf_mod);

Output Images:

Complete Model (Not Colored)

Complete Model Colored

Surface Model

Notes:

I have written the code in Matlab. I have used 107 voxels. I split the volume space into the total number of voxels and obtained the side of each voxel. I used this data to traverse all the voxel points. I used the projection matrices to project each voxel onto 2D space. A voxel which projected onto the white portions of all the silhouette images is a part of the 3D reconstruction, while the one which is not is a free space.

I identified the surface points only and created a separate model, but it doesn’t resemble the dancer as well as the complete model does. I have attached the PLY files and the output images.

For Coloring the voxels, I used the last image as it provided the most correct resemblance to the actual dancer. I wanted to use color correlation, however, could not find sufficient algorithm details in the slides or the Internet.