In the improved algorithm, the pre-processed image is smoothed and the proper gradientthreshold is set to prevent the generation of insignificant regions.
该改进算法在预处理阶段对图像进行平滑操作并设置适当的梯度阈值，即减少了梯度图像中非重要区域的产生。
2
In order to remove the residual noise which can not be smoothed by filter, the smoothing coefficient and constrain coefficient were used to threshold the gradient image.
为了消除噪声残留，引入了平滑系数与限制强度系数对梯度图作阈值化处理。
3
The method is presented to determine formation average pressure and boundary pressure with threshold pressure gradient and injection-production ratio.