利用OpenCV生成關於某點的顏色徑向均勻漸變圖像

利用OpenCV生成關於某點的顏色徑向均勻漸變圖像:

1. #include "cv.h"
2. #include "highgui.h"
3. #include <math.h>
4. #pragma comment(lib,"highgui.lib")
5. #pragma comment(lib,"cxcore.lib")
6. #pragma comment(lib,"cv.lib")
7. int main( int argc, char** argv )
8. {
9. IplImage* image = cvCreateImage(cvSize(800,600),IPL_DEPTH_8U,3);
10. if(!image)
11. {
12. return -1;
13. }
14. CvScalar a=CV_RGB(0,255,0);
15. CvScalar b=CV_RGB(0,0,0);
16. cvSet(image,a);
17. CvPoint origin=cvPoint(800,600);
18. CvPoint center=cvPoint(image->width/2,image->height/2);
19. double distance;
20. if(origin.x<=center.x && origin.y<=center.y)
21. {
22. distance=sqrt((image->width-1-origin.x)*(image->width-1-origin.x)+
23. (image->height-1-origin.y)*(image->height-1-origin.y));
24. }
25. else if(origin.x<=center.x && origin.y>center.y)
26. {
27. distance=sqrt((image->width-1-origin.x)*(image->width-1-origin.x)+
28. origin.y*origin.y);
29. }
30. else if(origin.x>center.x && origin.y<=center.y)
31. {
32. distance=sqrt(origin.x*origin.x+
33. (image->height-1-origin.y)*(image->height-1-origin.y));
34. }
35. else if(origin.x>center.x && origin.y>center.y)
36. {
37. distance=sqrt(origin.x*origin.x+origin.y*origin.y);
38. }
39. double weightB=(b.val[0]-a.val[0])/distance;
40. double weightG=(b.val[1]-a.val[1])/distance;
41. double weightR=(b.val[2]-a.val[2])/distance;
42. for(int i=0;i<image->width;i++)
43. {
44. for(int j=0;j<image->height;j++)
45. {
46. double dist=sqrt((i-origin.x)*(i-origin.x)+(j-origin.y)*(j-origin.y));
47. uchar* ptr = &CV_IMAGE_ELEM(image,uchar,j,i*3);
48. ptr[0] = cvRound(ptr[0]+weightB*dist);
49. ptr[1] = cvRound(ptr[1]+weightG*dist);
50. ptr[2] = cvRound(ptr[2]+weightR*dist);
51. }
52. }
53. cvSaveImage( "radial.jpg", image );
54. cvNamedWindow( "test", 1 );
55. cvShowImage( "test", image );
56. cvWaitKey();
57. cvDestroyWindow("test");
58. cvReleaseImage(&image);
59. return 0;
60. }

下圖是上面的代碼生成的效果圖。通過改寫上面代碼中的相關參數，主要是變量a，b和origin，可以生成更炫的漸變圖。

當修改為a=CV_RGB(0,255,0); b=CV_RGB(255,0,0);產生如下的圖像

當修改為a=CV_RGB(255,255,0);b=CV_RGB(0,0,255);origin=cvPoint(200,100);生成的圖像如下