图像锐化 Laplace算子 拉普拉斯算法不检测均匀的亮度变化，而是检测变化率的变化率，相当于二阶微分。计算出的图像更加突出亮度值突变的位置。-Image Sharpening Laplace operator Laplace algorithm does not detect uniform brightness changes, but the detection rate of change of the rate of change is equivalent to second-ord