compute blend weights offline

compute_weights.matlab

%% load std_expr captured data
clear;
dof=24;
header_file = fopen('start_frame.txt');%set header information file
i = 0;
while (1)   
    [name, count]= fscanf(header_file, '%s',1);
    if (count ==0) 
        break;
    end
    i=i+1;
    std_expr(i).name = name;
    std_expr(i).start = fscanf(header_file, '%d',1);
    std_expr(i).end = fscanf(header_file,'%d',1);    
end

size_of_expr = i; i=1;
while (strcmp(std_expr(i).name, 'base') == 0) i=i+1; end
if (i>size_of_expr) 
    print 'Error: No base expression';
else
    base_id = i; %fix to be the first
end

for i=1:size_of_expr
    name = sprintf('%s.dat',std_expr(i).name);
    tmp = load(name); tmp = tmp(std_expr(i).start+1:std_expr(i).end, 13:36);
    std_expr(i).frames = tmp;
    std_expr(i).avg = mean(tmp);     
end

%% process data (default)
metric = eye(dof);
basis = zeros(size_of_expr-1, dof);
for i=2:size_of_expr
    basis(i-1,:) = std_expr(i).avg - std_expr(base_id).avg;
end

% compute intra-variance
intra_var = zeros(dof);
inter_var = zeros(dof);
for i=1:size_of_expr
    F = std_expr(i).frames;
    F = F - repmat(std_expr(i).avg, size(F,1),1);
    intra_var = intra_var + F'*F /size(F,1);
end
intra_var = intra_var / size_of_expr;

for i=2:size_of_expr
    inter_var = inter_var + basis(i-1,:)' * basis(i-1,:);
end

for i=2:size_of_expr
    for j=i+1:size_of_expr
        inter_var = inter_var + (basis(i-1,:)' - basis(j-1,:)')*(basis(i-1,:) - basis(j-1,:));
    end
end
inter_var = inter_var / ((size_of_expr)*(size_of_expr+1)/2);

[V, D] = eig(inter_var - intra_var, intra_var);
[D, IDX] = sort(diag(D),'descend');
V = V(:,IDX); D=sqrt(sqrt(D/D(1)));
D(D<0) = 0;  %D(D>0) = 1; 
V= V*diag(D);   
metric = metric + V*V';

%% compute weights for motion data(optimizer)
tmp = load('tracking.dat'); 
motion = tmp(:,13:36);
total_frames = size(motion,1);
motion = motion - repmat(std_expr(base_id).avg, total_frames,1);
xopt = zeros(total_frames,size_of_expr-1);
A = eye(size_of_expr-1);
b = ones(size_of_expr-1,1);
xmin = zeros(size_of_expr-1,1);
H = basis*metric*basis'; H = (H + H')/2;
f0 = -basis*metric;
for i=1:total_frames      
    f = f0*motion(i,:)';
    xopt(i,:)= qpdantz(H,f,A,b,xmin);
end

dlmwrite('tracking_weights.dat',xopt,'delimiter',' ');%write weights
dlmwrite('tracking_weights.dat',[num2str(total_frames) 13 10 fileread('tracking_weights.dat')],'delimiter','');