docs: public void pixelToMarker( double pixelX , double pixelY , Point2D_F64 marker ) {
  
  		// find pointing vector in camera reference frame
  		pixelToNorm.compute(pixelX,pixelY,marker);
  		cameraP3.set(marker.x,marker.y,1);
  
  		// rotate into marker reference frame
  		GeometryMath_F64.multTran(outputFiducialToCamera.R,cameraP3,ray.slope);
  		GeometryMath_F64.multTran(outputFiducialToCamera.R,outputFiducialToCamera.T,ray.p);
  		ray.p.scale(-1);
  
  		double t = -ray.p.z/ray.slope.z;
  
  		marker.x = ray.p.x + ray.slope.x*t;
  		marker.y = ray.p.y + ray.slope.y*t;
  	}