用于图像边缘的羽化操作。主要有两种羽化操作，与另一个源码（均为matlab）向背景羽化操作不同的是，这是向白色进行过渡，即在图像边缘进行由图像到白色过渡的处理。-Feathering operation for image edge. The main the two feathering operating feathering operation and another source (both matlab) to the background is different, this is