MarimontOTF::MarimontOTF( const ViewingConditions &viewCond,
int cols, int rows, float adaptationLuminance )
{
const float n_p = 1.336;
const float f_p = 22.2888e-3;
const float D0 = n_p/f_p;
const float c = 3.434e3;
const float q1 = 1.7312;
const float q2 = 0.63346;
const float q3 = 0.21410;
filter = new pfs::Array2DImpl( cols/2+1, rows/2+1 );
int filterWidth=filter->getCols();
int filterHeight=filter->getRows();
float meanObserverDistance = (viewCond.minDistance + viewCond.maxDistance)/2;
float pix_per_deg = viewCond.getPixelsPerDegree( meanObserverDistance );
float x_norm = 0.5 / filterWidth, y_norm = 0.5 / filterHeight;
float dx, dy;
int x, y;
float p = getPupilDiameter( adaptationLuminance );
std::cerr << "Creating OTF filter..";
std::cerr << "(pupil diameter " << p*1e3 << "mm for adaptation lum " << adaptationLuminance << "cd/m^2)";
for (y = 0, dy = 0.0; y < filterHeight; y ++, dy += y_norm)
{
for (x = 0, dx = 0.0; x < filterWidth; x ++, dx += x_norm)
{
float v = pix_per_deg * sqrtf((float)(dx * dx + dy * dy));
if( v == 0 ) v = 0.1;
const int lefSize = sizeof( luminanceEfficiencyFunction ) / sizeof( SpectralSensitivity );
float H = 0;
for( int l = 0; l < lefSize; l++ ) {
const float lambda = luminanceEfficiencyFunction[l].lambda*1e-9;
const float s = c*(lambda / (D0*p)) * v;
const float D_lambda = q1 - (q2/(lambda*1e6-q3));
const float w20 = p*p/2 * D0 * D_lambda / (D0 + D_lambda);
const float alpha = 4*M_PI/lambda * w20 * fabsf( s );
const float py_max = sqrtf( (1-(s/2))*(1-(s/2)) );
const float dpy = py_max/10;
float h = 0;
for( float py = 0; py <= py_max; py += dpy ) {
h += 4/(M_PI*alpha)*sinf( alpha*(sqrtf(1 - py*py) - fabsf(s)/2) )*dpy;
}
H += h*luminanceEfficiencyFunction[l].weight;
}
(*filter)(x,y) = H * (0.3481+0.6519*exp(-0.1212*v));
}
}
(*filter)(0,0) = max( (*filter)(1,0), (*filter)(0,1) );
normalizeToMax( filter );
dumpImageAspect->dump( "filter_otf.pfs", filter, "Y" );
std::cerr << ".\n";
}
