sustaining_gazes/matlab_version/face_validation/paw_helpers/InitialisePieceWiseAffine.m

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2016-04-28 19:40:36 +00:00
function [ alphas, betas, triX, mask, xmin, ymin, npix ] = InitialisePieceWiseAffine( triangulation, sourcePoints )
%INITIALISEPIECEWICEAFFINE Summary of this function goes here
% Detailed explanation goes here
triangulation = triangulation + 1;
numPoints = size(sourcePoints, 1);
numTris = size(triangulation, 1);
alphas = zeros(size(triangulation, 1), 3);
betas = zeros(size(triangulation, 1), 3);
xs = sourcePoints(:,1);
ys = sourcePoints(:,2);
for i = 1:numTris
j = triangulation(i, 1);
k = triangulation(i, 2);
l = triangulation(i, 3);
c1 = ys(l) - ys(j);
c2 = xs(l) - xs(j);
c4 = ys(k) - ys(j);
c3 = xs(k) - xs(j);
c5 = c3*c1 - c2*c4;
alphas(i, 1) = (ys(j) * c2 - xs(j) * c1) / c5;
alphas(i, 2) = c1/c5;
alphas(i, 3) = -c2/c5;
betas(i, 1) = (xs(j) * c4 - ys(j) * c3)/c5;
betas(i, 2) = -c4/c5;
betas(i, 3) = c3/c5;
end
xmin = min(xs);
ymin = min(ys);
xmax = max(xs);
ymax = max(ys);
w = int32(xmax - xmin + 1);
h = int32(ymax - ymin + 1);
mask = zeros(h, w);
triX = zeros(h, w);
shape = [xs, ys];
for i = 1:h
for j = 1:w
currTri = findTriangle(double([double(j)-1+xmin, double(i)-1+ymin])', triangulation, shape);
if(currTri ~= -1)
triX(i, j) = currTri - 1;
mask(i, j) = 1;
else
triX(i, j) = -1;
end
end
end
npix = sum(sum(mask));
end
function [tri] = findTriangle(point, tris, controlPoints)
numTris = size(tris, 1);
tri = -1;
for i=1:numTris
if(PointInTriangle(point, controlPoints(tris(i,1),:)', controlPoints(tris(i,2),:)', controlPoints(tris(i,3),:)'))
tri = i;
break;
end
end
end
function inTriangle = PointInTriangle(point, v1, v2, v3)
inTriangle = SameSide(point, v1,v2,v3) && SameSide(point, v2,v1,v3) && SameSide(point, v3,v1,v2);
end
function sameSide = SameSide(toTest,v1,v2,v3)
x0 = toTest(1);
y0 = toTest(2);
x1 = v1(1);
x2 = v2(1);
x3 = v3(1);
y1 = v1(2);
y2 = v2(2);
y3 = v3(2);
x = (x3-x2)*(y0-y2) - (x0-x2)*(y3-y2);
y = (x3-x2)*(y1-y2) - (x1-x2)*(y3-y2);
if(x*y >= 0)
sameSide = 1;
else
sameSide = 0;
end
% cross1 = cross( v3 - v2, toTest - v2);
% cross2 = cross( v3 - v2, v1 - v2);
%
% sameSide = (cross1 * cross2') >= 0;
end