【学习opencv】对图像缩放并进行边缘检测

首先对图像进行缩放：

用到的函数：cvPyrDown();下面函数返回缩放后的图像

IplImage* doPyrDown(IplImage* in,int filter = IPL_GAUSSIAN_5x5)
{
	assert( in->width%2 == 0 && in->height%2 == 0 );
	IplImage* out = cvCreateImage( 
		cvSize( in->width/2, in->height/2 ),
		in->depth,
		in->nChannels
		);
	cvPyrDown( in, out );//使用Gaussian金字塔分解对输入图像向下采样，输出图像的宽度和高度是输入图像的一半
	return( out );
};

int main( int argc, char** argv )
{
	const char* cNamesmooth="smooth.jpg";
	IplImage* img = cvLoadImage( cNamesmooth);
	IplImage* img2 = cvCreateImage( cvSize( img->width/2,img->height/2 ), img->depth, img->nChannels);
	cvNamedWindow("Example1", CV_WINDOW_AUTOSIZE );
	cvNamedWindow("Example2", CV_WINDOW_AUTOSIZE );
	cvShowImage("Example1", img );
	img2 = doPyrDown( img );
	cvShowImage("Example2", img2 );
	cvWaitKey(0);
	cvReleaseImage( &img );
	cvReleaseImage( &img2 );
	cvDestroyWindow("Example1");
	cvDestroyWindow("Example2");
}

边缘检测使用了Canny边缘检测：

IplImage* doCanny(	IplImage* in,double  lowThresh,	double highThresh,double  aperture)
{
	if (in->nChannels != 1)
		return(0); // Canny only handles gray scale images
	IplImage* out = cvCreateImage(cvGetSize( in ),		in->depth, //IPL_DEPTH_8U,    
		1);
	cvCanny( in, out, lowThresh, highThresh, aperture );
	return( out );
};

可以使用两次缩放对图像进行边缘检测。

代码见资源：http://download.csdn.net/detail/u010141025/7016239