code: private void perturb(double disturbance , Point2D_F64 pixel , Point2D3D p23 ) {
  		double x;
  		double y = pixel.y;
  
  		x = pixel.x + disturbance;
  		computeDisturbance( x,y, p23);
  		x = pixel.x - disturbance;
  		computeDisturbance( x,y, p23);
  		x = pixel.x;
  		y = pixel.y + disturbance;
  		computeDisturbance( x,y, p23);
  		y = pixel.y - disturbance;
  		computeDisturbance( x,y, p23);
  	}
docs: Perturb the observation in 4 different ways
  
  @param disturbance distance of pixel the observed point will be offset by
  @param pixel observed pixel
  @param p23 observation plugged into PnP