void OpenCVPicture::colorDistortion(RNG &rng, int sigma1, int sigma2,
int sigma3, int sigma4) {
// Call as a final preprocessing step, after any affine transforms and
// jiggling.
assert(mat.type() % 8 == 5); // float
std::vector<float> delta1(mat.channels());
std::vector<float> delta2(mat.channels());
std::vector<float> delta3(mat.channels());
std::vector<float> delta4(mat.channels());
for (int j = 0; j < mat.channels(); j++) {
delta1[j] = rng.normal(0, sigma1);
delta2[j] = rng.normal(0, sigma2);
delta3[j] = rng.normal(0, sigma3);
delta4[j] = rng.normal(0, sigma4);
}
float *matData = ((float *)(mat.data));
for (int y = 0; y < mat.rows; y++) {
for (int x = 0; x < mat.cols; x++) {
int j = x * mat.channels() + y * mat.channels() * mat.cols;
bool interestingPixel = false;
for (int i = 0; i < mat.channels(); i++)
if (std::abs(matData[i + j] - backgroundColor) > 2)
interestingPixel = true;
if (interestingPixel) {
for (int i = 0; i < mat.channels(); i++)
matData[i + j] +=
delta1[i] + delta2[i] * (matData[i + j] - backgroundColor) +
delta3[i] * (x - mat.cols / 2) + delta4[i] * (y - mat.rows / 2);
}
}
}
}
main(int argc, char* argv[]){
static vec u(K+1);
int k,n;
std::string op=argv[1]; // command line argument
val dx=1.0/K, dt=T/N, dx4=dx*dx*dx*dx, xk, tn; // discretization variables
// Initialize
for(k=0;k<=K;k++){
xk=k*dx;
u(k)=f(xk);
}
if(op=="plot") printf("set terminal x11 noraise\nset yrange [-5:5]\nset style data lines\n\n");
val rho=NU*dt/dx4; // rho = nu*dt/dx^4
vec temp(K+1);
temp=u;
for(n=0;n<=N;n++){
tn=n*dt;
u=temp;
for(k=0;k<=K;k++){
xk=k*dx;
temp(k) = u(k) - rho*delta4(u,k);
//printu(u,tn,xk,K);
}
if(op=="plot0") plot0(u, tn, K-1, N);
if(op=="plot1") plot1(u, tn, K-1, N);
if(op=="plot3d") plot3d(u, tn, K-1, N);
if(op=="approx") output(tn, 0.5, u(K/2), K-1, N);
}
return 0;
}
void distortImageColor(cv::Mat& mat, RNG& rng, float sigma1, float sigma2, float sigma3, float sigma4) {
std::vector<float> delta1(mat.channels());
std::vector<float> delta2(mat.channels());
std::vector<float> delta3(mat.channels());
std::vector<float> delta4(mat.channels());
for (int j=0;j<mat.channels();j++) {
delta1[j]=rng.normal(0,sigma1);
delta2[j]=rng.normal(0,sigma2);
delta3[j]=rng.normal(0,sigma3);
delta4[j]=rng.normal(0,sigma4);
}
int j=0;
for (int y=0;y<mat.rows;++y) {
for (int x=0;x<mat.cols;++x) {
for (int i=0;i<mat.channels();++i) {
mat.ptr()[j]=std::max(0,std::min(255,
(int)(mat.ptr()[j]+
delta1[i]+
delta2[i]*cos(mat.ptr()[j]*3.1415926535/255)+
delta3[i]*(x-mat.cols/2)+
delta4[i]*(y-mat.rows/2))));
++j;
}
}
}
}
int main(){
static vec u(K+1), un(K+1);
val dt = T/N;
val dx = 1.0/K;
val gam = MU*dt/(dx*dx);
val rho = NU*dt/(dx*dx*dx*dx);
val ar = dt/(2*dx);
int j,n=1;
//Initialize U
for (j=0;j<K+1;j++) u(j)=f(j*dx);
//printf("Initial vector\n"); vecprintf(u,K);
val tn = n*dt;
while (tn<=T||n<N){
for (j=0;j<K+1;j++) un(j) = u(j) - gam*delta2(u,j) - rho*delta4(u,j) - ar*u(j)*delta0(u,j);
for (j=0;j<K+1;j++) u(j) = un(j);
n+=1;
tn = n*dt;
}
printf("At t = 0.25 and space 0.5 the 'heat' is %24.15e\n", u(K/2));
return 0;
}
