利用OpenCV繪制圖像上某直線區域的RGB強度分布圖

首先，不知道這篇文章的標題合不合適，呵呵，大家有沒有更合適的標題呢。

這篇博文是在前兩篇的基礎上寫的，大家可以參看一下。下面貼代碼了。

相關鏈接：

http://www.linuxidc.com/Linux/2012-09/70010.htm
http://www.linuxidc.com/Linux/2012-09/70011.htm

1. #include <cv.h>
2. #include <highgui.h>
3. #include <stdio.h>
4. #pragma comment( lib, "cv.lib" )
5. #pragma comment( lib, "cxcore.lib" )
6. #pragma comment( lib, "highgui.lib" )
7. IplImage* org = 0;
8. IplImage* img = 0;
9. IplImage* tmp = 0;
10. IplImage* msk = 0;
11. IplImage* dst = 0 ;
12. void on_mouse( int event, int x, int y, int flags, void* ustc)
13. {
14. static CvPoint pre_pt = {-1,-1};
15. static CvPoint cur_pt = {-1,-1};
16. CvFont font;
17. cvInitFont(&font, CV_FONT_HERSHEY_SIMPLEX, 0.5, 0.5, 0, 1, CV_AA);
18. char temp[16];
20. if( event == CV_EVENT_LBUTTONDOWN )
21. {
22. cvCopy(org,img);
23. sprintf(temp,"(%d,%d)",x,y);
24. pre_pt = cvPoint(x,y);
25. cvPutText(img,temp, pre_pt, &font, cvScalar(0,0, 0, 255));
26. cvCircle( img, pre_pt, 3,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );
27. cvShowImage( "image", img );
29. cvCopy(img,tmp);
30. }
31. else if( event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON))
32. {
33. cvCopy(tmp,img);
34. sprintf(temp,"(%d,%d)",x,y);
35. cur_pt = cvPoint(x,y);
36. cvPutText(img,temp, cur_pt, &font, cvScalar(0,0, 0, 255));
37. cvLine(img, pre_pt, cur_pt, cvScalar(0,255,0,0), 1, CV_AA, 0 );
38. cvShowImage( "image", img );
39. }
40. else if( event == CV_EVENT_LBUTTONUP )
41. {
42. sprintf(temp,"(%d,%d)",x,y);
43. cur_pt = cvPoint(x,y);
44. cvPutText(img,temp, cur_pt, &font, cvScalar(0,0, 0, 255));
45. cvCircle( img, cur_pt, 3,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );
46. cvLine( img, pre_pt, cur_pt, cvScalar(0,255,0,0), 1, CV_AA, 0 );
47. cvSetZero(msk);
48. cvLine( msk, pre_pt, cur_pt, cvScalar(255,255,255,0), 1, CV_AA, 0 );
49. cvShowImage( "image", img );
50. int width=org->width;
51. int height=org->height;
52. int step=org->widthStep;
53. uchar *data=(uchar*)org->imageData;
54. int mask_step=msk->widthStep;
55. uchar *mask_data=(uchar*)msk->imageData;
56. cvSet(dst,cvScalar(255,255,255));
57. int length=cvCeil(sqrt((pre_pt.x-cur_pt.x)*(pre_pt.x-cur_pt.x)+(pre_pt.y-cur_pt.y)*(pre_pt.y-cur_pt.y)));
58. double bin_width=(double)dst->width/length;
59. double bin_height=(double)dst->height/255;
60. int count=0;
61. for(int i=0;i<width;i++)
62. {
63. for(int j=0;j<height;j++)
64. {
65. if(mask_data[j*mask_step+i]!=0)
66. {
67. CvPoint pt;
68. pt=cvPoint(bin_width*count,(dst->height-data[j*step+i*3+2])*bin_height);
69. cvCircle(dst, pt,1,cvScalar(0,0,255,0) ,CV_FILLED, CV_AA, 0 );
70. pt=cvPoint(bin_width*count,(dst->height-data[j*step+i*3+1])*bin_height);
71. cvCircle(dst, pt,1,cvScalar(0,255,0,0) ,CV_FILLED, CV_AA, 0 );
72. pt=cvPoint(bin_width*count,(dst->height-data[j*step+i*3])*bin_height);
73. cvCircle(dst, pt,1,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );
74. count++;
75. }
76. }
77. }
79. cvNamedWindow("dst",1);
80. cvShowImage("dst",dst);
81. }
82. }
83. int main()
84. {
85. org=cvLoadImage("lena.jpg",1);
86. img=cvCloneImage(org);
87. tmp=cvCloneImage(org);
88. msk=cvCreateImage(cvSize(img->width,img->height),8,1);
89. cvSetZero(msk);
90. dst=cvCreateImage(cvSize(400,300),8,3);
91. cvSet(dst,cvScalar(255,255,255));
92. cvNamedWindow("image",1);
93. cvSetMouseCallback( "image", on_mouse, 0 );
94. cvShowImage("image",img);
95. cvWaitKey(0);
96. cvDestroyAllWindows();
97. cvReleaseImage(&org);
98. cvReleaseImage(&img);
99. cvReleaseImage(&tmp);
100. cvReleaseImage(&msk);
101. cvReleaseImage(&dst);
102. return 0;
103. }

效果圖如下，上圖是繪線窗口，下圖是線上的RGB強度分布圖。

這裡離散的顯示分布圖，大家有沒有方法使連續起來呢？