Laplace 算子
二階微分算子
根據差分近似：
![\bigtriangledown ^2f=[f(x+1,y)+f(x-1,y)+f(x,y+1)+f(x,y-1)]-4f(x,y)](https://pic1.xuehuaimg.com/proxy/csdn/https://private.codecogs.com/gif.latex?%5Cbigtriangledown%20%5E2f%3D%5Bf%28x+1%2Cy%29+f%28x-1%2Cy%29+f%28x%2Cy+1%29+f%28x%2Cy-1%29%5D-4f%28x%2Cy%29)
它的Filter mask的形式如下：
拉普拉斯圖像處理
Laplace 銳化
在原圖上添加 灰度突變的區域 得到新的圖
![g(x,y)=f(x,y)+c[\bigtriangledown ^2f(x,y)]](https://pic1.xuehuaimg.com/proxy/csdn/https://private.codecogs.com/gif.latex?g%28x%2Cy%29%3Df%28x%2Cy%29+c%5B%5Cbigtriangledown%20%5E2f%28x%2Cy%29%5D)
