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 okprintf("channels = %d\n", in->nChannels);//if(1 != in->nChannels)// return NULL;printf("start processing...\n");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\n");IplImage *image;  /* todo:how to judge load fail?*/image = cvLoadImage(argv[1]);  if(argc != 2)  {  std::cout << "No image data\n";  return -1;  }  /*image_smooth(image);
*/cvNamedWindow("image input");cvNamedWindow("image output");//IplImage *img1 = doPyrDown(image);//#1IplImage *img1 = doCanny(image, 10, 100, 3);//#2cvShowImage("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）：