【练习6.5】

题目要求：

优秀代码参考：

 1 #include <iostream>
 2 #include <cv.h>
 3 #include <highgui.h>
 4 #include <cxcore.h>
 5
 6 using namespace std;
 7 const CvSize size = cvSize(200,200);
 8 const int aperture[] = {3,5,9,11,13,17};
 9 int main()
10 {
11     IplImage *src = cvCreateImage(size,8,1);
12     cvZero(src);
13     cvLine(src
14         //,cvPoint(0,size.height - 1)
15         //,cvPoint(size.width -1 , 0)
16         ,cvPoint(0,0)
17         ,cvPoint(size.width - 1, size.height - 1)
18         ,CV_RGB(255,255,255)
19         ,3
20         );
21     cvShowImage("src",src);
22
23     IplImage *deriv_x = cvCreateImage(size,IPL_DEPTH_32F,1);
24     IplImage *deriv_y = cvCreateImage(size,IPL_DEPTH_32F,1);
25     IplImage *magnitude = cvCreateImage(size,IPL_DEPTH_32F,1);
26     IplImage *angle = cvCreateImage(size,IPL_DEPTH_32F,1);
27     IplImage *mask = cvCreateImage(size,IPL_DEPTH_8U,1);
28     for(int i=0;i<sizeof(aperture)/sizeof(aperture[0]);++i){
29         cvSobel(src,deriv_x,1,0,aperture[i]);
30         cvSobel(src,deriv_y,0,1,aperture[i]);
31
32         cvCartToPolar(deriv_x,deriv_y,magnitude,angle,1);
33
34         cvSave("x.xml",deriv_x);
35         cvSave("y.xml",deriv_y);
36         cvSave("magnitude.xml",magnitude);
37         cvSave("angle.xml",angle);
38
39         double max_mag ,min_mag ,max_angle , min_angle;
40         cvMinMaxLoc(magnitude,&min_mag,&max_mag);
41         cvMinMaxLoc(angle,&min_angle,&max_angle);
42         cout<<"magnitude: max = "<<max_mag<<" min = "<<min_mag<<endl;
43         cout<<"angle : max = "<<max_angle<<" min = "<<min_angle<<endl;
44
45         cvCmpS(magnitude,max_mag*3/4,mask,CV_CMP_GT);
46         cvShowImage("mask",mask);
47
48         CvScalar scalar = cvAvg(angle,mask);
49         cout<<"aperture = "<<aperture[i]<<", line angle = "<<scalar.val[0]<<endl;
50         cvWaitKey();
51     }
52     cvReleaseImage(&src);
53     cvReleaseImage(&magnitude);
54     cvReleaseImage(&angle);
55     cvReleaseImage(&mask);
56     cvDestroyAllWindows();
57
58 }

源自：学习opencv第六章习题5 , 使用x,y阶层数求出图像内唯一直线的角度

程序代码：

结果图片：

要言妙道：