code: protected void interpolateFlowScale(int widthNew, int heightNew) {
  		initFlowX.reshape(widthNew,heightNew);
  		initFlowY.reshape(widthNew,heightNew);
  
  		interpolateFlowScale(flowX, initFlowX);
  		interpolateFlowScale(flowY, initFlowY);
  
  		flowX.reshape(widthNew,heightNew);
  		flowY.reshape(widthNew,heightNew);
  
  		// init flow contains the initial estimate of the flow vector (if available)
  		// flow contains the estimate for each iteration below
  		flowX.setTo(initFlowX);
  		flowY.setTo(initFlowY);
  	}
docs: Provides an initial estimate for the flow by interpolating values from the previous layer.