アンシャープマスク
In the example below, the image is convolved with the following sharpening filter:
Sharpen filter [ 0 − 1 0 − 1 5 − 1 0 − 1 0 ] {\displaystyle {\begin{bmatrix}\ \ 0&-1&\ \ 0\\-1&\ \ 5&-1\\\ \ 0&-1&\ \ 0\end{bmatrix}}}
This matrix is obtained using the equation shown above under #Digital unsharp masking, using a uniform kernel with 5 pixels for the "blurred" image, and 5 for the "amount" multiplier: