Computing the Hough Transform

Listing 3: Rewriting the accumulation loop.

x -= dx/2;   y -= dy/2;
for (thetaIndex=0; thetaIndex<cosTable.size(); thetaIndex++)  
{
  rho = rhoMax + x*cosTable[thetaIndex] + y*sinTable[thetaIndex];
  rho >>= 1; // represents a rhoDivisor of 2
  accum[thetaIndex][(int)rho]++;
}