The gradient templates were applied to extract detail signals in predicting lifting step, and all kinds of morphological operators ( max, min, median and so on ) were used as update operators to update the low-pass signals 预测步骤时,采用指定的梯度模板提取信号中的细节信息;更新步骤中用最大、最小和中值等各种形态算子来获取低频信息。