Opencv step by step

这里举出三个案例：

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


void image_smooth(IplImage * image)
{
	cvNamedWindow("#1image input");
	cvShowImage("#1image input", image);	
	
	/* create 8 bit 3 channel image*/
	IplImage *out_image = cvCreateImage(cvGetSize(image), IPL_DEPTH_8U, 3);
	/* smooth 3*3 around every point */
	cvSmooth(image, out_image, CV_GAUSSIAN, 3, 3);
	cvNamedWindow("#1image output");
	cvShowImage("#1image output", out_image);

	cvReleaseImage(&out_image);
	cvWaitKey(0);
	
	cvDestroyWindow("#1image input");
	cvDestroyWindow("#1image output");
}

IplImage *doPyrDown(IplImage *in)
{
	IplImage *out = cvCreateImage(cvSize(in->width/2, in->height/2) ,in->depth, in->nChannels);
	cvPyrDown(in, out);
	return out;
}

IplImage *doCanny(IplImage *in, double lowTh, double highTh, double aperture)
{
	//3 channel is ok
	printf("channels = %d
", in->nChannels);
	//if(1 != in->nChannels)
	//	return NULL;
	printf("start processing...
");
	IplImage *out = cvCreateImage(cvGetSize(in), IPL_DEPTH_8U, 1);
	cvCanny(in, out, lowTh, highTh, aperture);
	return out;
}


int main(int argc,char **argv)
{


	printf("this is image transforming
");
        IplImage *image;  
	/* todo:how to judge load fail?*/
        image = cvLoadImage(argv[1]);  
      
        if(argc != 2)  
        {  
            std::cout << "No image data
";  
            return -1;  
        }  

/*
	image_smooth(image);
*/

	cvNamedWindow("image input");
	cvNamedWindow("image output");
	//IplImage *img1 = doPyrDown(image);//#1
	IplImage *img1 = doCanny(image, 10, 100, 3);//#2

	cvShowImage("image input", image);	
	cvShowImage("image output", img1);	
	cvReleaseImage(&image);
	cvReleaseImage(&img1);
	cvWaitKey(0);
	cvDestroyWindow("image input");
	cvDestroyWindow("image output");





	return 0;
}

其中，

image_smooth

是将图像平滑处理。

其中关键的一行是

	cvSmooth(image, out_image, CV_GAUSSIAN, 3, 3);

效果如下：

这样处理后，图片变模糊了。

doPyrDown

是图像变成原来的0.25倍，它调用的

cvPyrDown

函数对于传入参数有较严格的要求，传入的两个图像要接近0.25倍，详情看官方文档.

doCanny

是进行边缘检测，虽然书中不支持三通道的，但是代码里面是支持的，所以我直接传了张一般的图片进去。。

效果如下（女神 奥黛丽·赫本）：