Learning opencv -- initialize the first frame of the video.

This article from http://blog.csdn.net/sangni007/article/details/8112486

In many video tracking or segmentation, you always need to initialize the first frame, that is, to draw a frame on the first frame, or to mark the foreground and background. Today, we will initialize the first frame, I drew a box of code on the first frame to implement it. By the way, I will review the mouse recall event in opencv and paste the code here to share it with you. It will also facilitate future search.

[CPP]
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1. # Include "opencv2/opencv. HPP"
   
2. # Include "opencv2/highgui. HPP"
3. # Include <string>
   
4. # Include <iostream>
5. # Include <stdio. h>
   
7. Using namespace CV;
8. Using namespace STD;
10. // You can trace up to one object;
11. # Define max_objects 1
    
13. // Class for passing Parameters
14. Class Params
15. {
16. Public:
18. Point loc1, loc2;
19. String win_name;
20. Mat SRC;
21. Mat cur;
22. Int N; // number of record objects
23. Params (): n (0 ){}
24. //~ Params ();
25. };
27. // Mouse event
28. Void mouseevent (INT event, int X, int y, int flags, void * PARAM)
29. {
30. Static bool check_line_state = false;
31. Mat TMP;
32. Params * P = (Params *) Param;
33. // Press the left mouse button to store the initial position;
34. If (event = cv_event_lbuttondown)
35. {
36. If (p-> N = max_objects) // you can check whether a trail object exists;
37. {
38. Cout <"fail! \ N only can tracking one object! "<Endl;
39. Return;
40. }
41. P-> loc1.x = X;
42. P-> loc1.y = y;
43. Check_line_state = true;
44. }
46. // Press the left mouse button and move the mouse to draw a rectangle;
47. Else if (check_line_state & event = cv_event_mousemove)
48. {
49. If (p-> N = max_objects) // you can check whether a trail object exists;
50. {
51. Cout <"fail! \ N only can tracking one object! "<Endl;
52. Return;
53. }
54. P-> SRC. copyto (TMP );
55. Rectangle (TMP, p-> loc1, point (x, y), cv_rgb (255, 0), 2, 8 );
56. Imshow (p-> win_name, TMP );
57. }
59. // The left button pops up and the frame ends;
60. Else if (event = cv_event_lbuttonup)
61. {
62. If (p-> N = max_objects) // you can check whether a trail object exists;
63. {
64. Cout <"fail! \ N only can tracking one object! "<Endl;
65. Return;
66. }
67. P-> loc2.x = X;
68. P-> loc2.y = y;
69. Rectangle (p-> SRC, p-> loc1, point (x, y), cv_rgb (255, 0, 0), 2, 8 );
70. Imshow (p-> win_name, p-> SRC );
71. P-> N ++;
72. Check_line_state = false;
73. }
74. }
76. // Initialize the first frame and draw the object to be tracked
77. Void initialvideo (MAT & SRC, rect & rect)
78. {
79. Params P;
80. SRC. copyto (P. SRC );
81. P. win_name = "initial window ";
82. Imshow (P. win_name, Src );
84. // Mouse recall event
85. Setmousecallback (P. win_name, & mouseevent, & P );
86. Cout <"Draw rect & press any key to end" <Endl;
88. Waitkey ();
90. // Assign the obtained position to the rect
91. Rect. x = min (P. loc1.x, P. loc2.x );
92. Rect. Y = min (P. loc1.y, P. loc2.y );
93. Rect. width = ABS (P. loc1.x-P. loc2.x );
94. Rect. Height = ABS (P. loc1.y-P. loc2.y );
96. Destroywindow ("initial window ");
97. }
99. Int main ()
100. {
101. // Input from default camera
102. Videocapture cap (0 );
103. // Input from the video
104. // String filename = "D:/soccer. Avi ";
     
105. // Videocapture cap (filename );
107. If (! Cap. isopened () // check if we succeeded
108. {
109. Cout <"couldn't open video file" <Endl;
110. Return-1;
111. }
113. Mat frame;
114. Bool isfirstframe = true;
115. Rect;
116. Cap> frame; // the first frame cannot be displayed due to a computer problem.
117. For (;;)
118. {
119. Cap> frame;
120. // Initialize the first frame
121. If (isfirstframe)
122. {
123. Initialvideo (frame, rect );
124. Isfirstframe = false;
125. }
126. // Other operations
127. Rectangle (frame, rect, cv_rgb (255, 0, 0), 2, 8 );
128. Imshow ("showsrc", frame );
129. Char key = (char) waitkey (5 );
130. Switch (key)
131. {
132. Case 27:
133. Return 0;
134. Case '':
135. Cout <"Save process" <Endl;
136. Break;
137. Default:
138. Break;
139. }
140. }
141. }

# Include "opencv2/opencv. HPP "# include" opencv2/highgui. HPP "# include <string> # include <iostream> # include <stdio. h> using namespace CV; using namespace STD; // trace up to one object; # define max_objects 1 // pass the classclass Params parameter {public: Point loc1, loc2; string win_name; mat src; MAT cur; int N; // number of record objects Params (): n (0 ){}//~ Params () ;}; // void mouseevent (INT event, int X, int y, int flags, void * PARAM) {static bool check_line_state = false; mat tmp; params * P = (Params *) Param; // press the left mouse button to store the initial position. If (event = cv_event_lbuttondown) {If (p-> N = max_objects) // determine whether a trail object exists; {cout <"fail! \ N only can tracking one object! "<Endl; return;} p-> loc1.x = x; P-> loc1.y = y; check_line_state = true;} // click the left mouse button and move the mouse to draw a rectangle; else if (check_line_state & event = cv_event_mousemove) {If (p-> N = max_objects) // you can check whether a trail object exists. {cout <"fail! \ N only can tracking one object! "<Endl; return;} p-> SRC. copyto (TMP); rectangle (TMP, p-> loc1, point (x, y), cv_rgb (255, 0, 0), 2, 8); imshow (p-> win_name, TMP);} // The left button pops up and the frame ends. Else if (event = cv_event_lbuttonup) {If (p-> N = max_objects) // determine whether a trail object exists; {cout <"fail! \ N only can tracking one object! "<Endl; return;} p-> loc2.x = x; P-> loc2.y = y; rectangle (p-> SRC, p-> loc1, point (X, y), cv_rgb (255, 0), 2, 8); imshow (p-> win_name, p-> SRC); P-> N ++; check_line_state = false ;}// initialize the first frame and draw the void initialvideo (MAT & SRC, rect & rect) {Params P; SRC. copyto (P. SRC); p. win_name = "initial window"; imshow (P. win_name, Src); // The mouse recall event setmousecallback (P. win_name, & mouseevent, & P); cout <"Draw rect & press any key to end "<Endl; waitkey (); // assign the obtained position to rectrect. X = min (P. loc1.x, P. loc2.x); rect. y = min (P. loc1.y, P. loc2.y); rect. width = ABS (P. loc1.x-P. loc2.x); rect. height = ABS (P. loc1.y-P. loc2.y); destroywindow ("initial window");} int main () {// input videocapture cap (0) from the default camera ); // input from the video // string filename = "D:/soccer. avi "; // videocapture cap (filename); If (! Cap. isopened () // check if we succeeded {cout <"couldn't open video file" <Endl; Return-1 ;}mat frame; bool isfirstframe = true; rect; Cap> frame; // It may be caused by a computer problem that the first frame cannot be displayed. Therefore, the first frame is read for (;) first (;;) {cap> frame; // initialize the first frame if (isfirstframe) {initialvideo (frame, rect); isfirstframe = false;} // other operations rectangle (frame, rect, cv_rgb (255, 0), 2, 8); imshow ("showsrc", frame); char key = (char) waitkey (5); Switch (key) {Case 27: return 0; Case '': cout <" Save process "<Endl; break; default: Break ;}}}