sobel导数边缘检测（一阶导数求边缘）

#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <stdlib.h>
#include <stdio.h>

using namespace cv;

/** @function main */
int main()
{

	Mat src, src_gray;
	Mat grad;
	char* window_name = "Sobel Demo - Simple Edge Detector";
	int scale = 1;
	int delta = 0;
	int ddepth = CV_16S;

	int c;

	/// 装载图像
	src = imread("demo.jpg");

	if (!src.data)
	{
		return -1;
	}

	GaussianBlur(src, src, Size(3, 3), 0, 0, BORDER_DEFAULT);

	/// 转换为灰度图
	cvtColor(src, src_gray, CV_RGB2GRAY);

	/// 创建显示窗口
	namedWindow(window_name, CV_WINDOW_AUTOSIZE);

	/// 创建 grad_x 和 grad_y 矩阵
	Mat grad_x, grad_y;
	Mat abs_grad_x, abs_grad_y;

	/// 求 X方向梯度
	//Scharr( src_gray, grad_x, ddepth, 1, 0, scale, delta, BORDER_DEFAULT );
	Sobel(src_gray, grad_x, ddepth, 1, 0, 3, scale, delta, BORDER_DEFAULT);
	convertScaleAbs(grad_x, abs_grad_x);

	/// 求Y方向梯度
	//Scharr( src_gray, grad_y, ddepth, 0, 1, scale, delta, BORDER_DEFAULT );
	Sobel(src_gray, grad_y, ddepth, 0, 1, 3, scale, delta, BORDER_DEFAULT);
	convertScaleAbs(grad_y, abs_grad_y);

	/// 合并梯度(近似)
	addWeighted(abs_grad_x, 0.5, abs_grad_y, 0.5, 0, grad);

	imshow(window_name, grad);

	waitKey(0);

	return 0;
}