拉普拉斯二階銳化 |0 |-1 |0 |-1|5|-1 | 0|-1 |0

#include "opencv2/opencv.hpp"
#include <iostream>

using namespace std;
using namespace cv;

//opencv mask(拉普拉斯銳化)
//0 -1 0
//-1 5 -1 
//0 -1 0
void sharp(const Mat& myImage, Mat& result)
{
	CV_Assert(myImage.depth() == CV_8U);
	const int channels = myImage.channels();
	cout << "channels= " << channels << endl;
	result.create(myImage.size(), myImage.type());  //創建於元素影象一樣型別的大小

	for (int j = 1; j < myImage.rows - 1; ++j)
	{
		const uchar* previous = myImage.ptr<uchar>(j - 1);
		const uchar* current = myImage.ptr<uchar>(j);
		const uchar* next = myImage.ptr<uchar>(j + 1);
		uchar* output = result.ptr<uchar>(j);//指向輸出影象的第j行的指標
		
		//內迴圈，按列掃描，此處相當於對每個通道單獨濾波
		for (int i = channels; i < channels*(myImage.cols - 1); ++i)
		{
			//掩碼運算元，銳化，二維拉普拉斯
			*output++ = saturate_cast<uchar>(6 * current[i] - current[i - channels] - current[i + channels] - previous[i] - next[i]);
		}
	}

	result.row(0).setTo(Scalar(0));
	result.row(result.rows - 1).setTo(Scalar(0));
	result.col(0).setTo(Scalar(0));
	result.col(result.cols - 1).setTo(Scalar(0));
}
int main()
{
	
	
	Mat a;
	a = imread("../../lena_color.tif", IMREAD_COLOR);
	if (a.empty())
		return - 1;
	imshow("original", a);
	Mat b;
	sharp(a, b);
	imshow("sharp", b);
	
	waitKey(0);
		return 0;
	}