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;
}