OpenCV几种边缘检测的方法

这里主要讲下通过 Sobel算子、Laplace算子、Canny算子来实现图像的边缘检测，先来看下Sobel算子的实现：

#include<cv.h>
#include<highgui.h>

int main()
{
	IplImage* pImage = NULL;
	IplImage* pImgSobelgray = NULL;
	IplImage* pImg8u = NULL;
	IplImage* pImg8uSmooth = NULL;
	IplImage* pImgColor = NULL;
	IplImage* pImgSobelcolor = NULL;
	IplImage* pImgPlanes[3] = {0,0,0};

	pImage = cvLoadImage ("1.jpg", 1);

	cvNamedWindow ("src", 1);
	cvShowImage ("src", pImage);

	/*灰度图的处理*/
	pImg8u = cvCreateImage (cvGetSize(pImage), IPL_DEPTH_8U, 1);
	pImg8uSmooth = cvCreateImage (cvGetSize(pImage), IPL_DEPTH_8U, 1);
	cvCvtColor (pImage, pImg8u, CV_BGR2GRAY);
	cvSmooth (pImg8u, pImg8uSmooth, CV_GAUSSIAN, 3, 0, 0);
	pImgSobelgray = cvCreateImage (cvGetSize(pImage), IPL_DEPTH_16S, 1);
	cvSobel (pImg8uSmooth, pImgSobelgray, 0, 1, 3);
	cvConvertScaleAbs (pImgSobelgray, pImg8u, 1, 0);
	cvNamedWindow ("Sobel gray Image", 1);
	cvShowImage ("Sobel gray Image", pImg8u);

	/*彩色图的处理*/
	int i;
	for (i = 0; i < 3; i++)
	{
		pImgPlanes[i] = cvCreateImage (cvSize(pImage->width, pImage->height), 8, 1);
	}
	pImgSobelcolor = cvCreateImage (cvSize(pImage->width, pImage->height), IPL_DEPTH_16S, 1);
	pImgColor = cvCreateImage (cvSize(pImage->width, pImage->height), 8, 3);
	cvCvtPixToPlane (pImage, pImgPlanes[0], pImgPlanes[1], pImgPlanes[2], NULL);
	for (i = 0; i < 3; i++)
	{
		cvSobel (pImgPlanes[i], pImgSobelcolor, 0, 1, 3);
		cvConvertScaleAbs (pImgSobelcolor, pImgPlanes[i], 1, 0);
	}
	cvCvtPlaneToPix (pImgPlanes[0], pImgPlanes[1], pImgPlanes[2], NULL, pImgColor);
	cvNamedWindow ("Sobel color Image", 1);
	cvShowImage ("Sobel color Image", pImgColor);

	cvWaitKey (0);

	cvReleaseImage (&pImage);
	cvReleaseImage (&pImgSobelgray);
	cvReleaseImage (&pImgSobelcolor);
	cvReleaseImage (&pImg8u);
	cvReleaseImage (&pImg8uSmooth);
	cvReleaseImage (&pImgColor);

	return 0;
}

对于利用Laplace算子实现边缘检测可以说和Sobel是一模一样的，这里就不再给出代码啦！

下面看下最后一个代码，即Canny算子实现边缘检测，其实基本也和前面是一样的，唯一的区别在于转换时的目标图像。对于前两个来说，当输入图像是8位时，要求输出图像是16位，但Canny则不需要。看Canny的代码：

#include<cv.h>
#include<highgui.h>

int main()
{
	IplImage* pImage = NULL;
	IplImage* pImgCanny = NULL;
	IplImage* pImg8u = NULL;
	IplImage* pImg8uSmooth = NULL;

	pImage = cvLoadImage ("1.jpg", 1);
	
	cvNamedWindow ("src", 1);
	cvShowImage ("src", pImage);

	pImg8u = cvCreateImage (cvGetSize(pImage), IPL_DEPTH_8U, 1);
	pImg8uSmooth = cvCreateImage (cvGetSize(pImage), IPL_DEPTH_8U, 1);
	pImgCanny = cvCreateImage (cvGetSize(pImage), IPL_DEPTH_8U, 1);
	cvCvtColor (pImage, pImg8u, CV_BGR2GRAY);
	cvSmooth (pImg8u, pImg8uSmooth, CV_GAUSSIAN, 3, 0, 0);
	cvCanny (pImg8uSmooth, pImgCanny, 100, 200, 3);
	cvConvertScaleAbs (pImgCanny, pImg8u, 1, 0);

	cvNamedWindow ("Canny Image", 1);
	cvShowImage ("Canny Image", pImg8u);

	cvWaitKey (0);

	cvReleaseImage (&pImage);
	cvReleaseImage (&pImgCanny);
	cvReleaseImage (&pImg8u);
	cvReleaseImage (&pImg8uSmooth);

	return 0;
}