code: public void process( double c_x , double c_y , double sigma )
  	{
  		// convert to image coordinates
  		int x = (int)(c_x + 0.5);
  		int y = (int)(c_y + 0.5);
  
  		// Estimate its orientation(s)
  		computeHistogram(x, y, sigma );
  
  		// compute the descriptor
  		findHistogramPeaks();
  	}
docs: Estimates the orientation(s) of a region at the specified location and scale
  
  @param c_x Location x-axis
  @param c_y Location y-axis
  @param sigma blur standard deviations of detected feature.  Also referred to as scale.