opencv-Video Processing-draw area of interest (ROI)

The Division of area of interest, in the video processing has an important application, with OPENCV introduction of two, in the video annotated area of interest method:

Original video:

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First: Pause the video or draw an area of interest in the first frame of the video stream

#include <opencv2\core\core.hpp> #include <opencv2\highgui\highgui.hpp> #include <opencv2\imgproc\ Imgproc.hpp>using namespace CV; #include <iostream> #include <vector>using namespace std;/*---- Define mouse events-Draw rectangular areas: function as two headlights----*///first step: global variable bool Drawing_box = False;bool Gotbox = false; Rect box; Point downpoint;/*void mouserecthandler (int event, int x, int y, int. flags, void *param) {switch (event) {case cv_event_mous Emove:if (drawing_box) {box.width = X-box.x;box.height = y-box.y;} Break;case Cv_event_lbuttondown:drawing_box = True;box = Rect (x, y, 0, 0); Break;case cv_event_lbuttonup:drawing_box = Fal Se;gotbox = true;if (Box.width < 0) {box.x + = Box.width;box.width *=-1;} if (Box.height < 0) {box.y + = Box.height;box.height *=-1;} Break;default:break;}} */void Mouserecthandler (int event, int x, int y, int flags, void *param) {switch (event) {Case Cv_event_mousemove:if (Drawin G_box) {//The mouse moves to the lower-right corner of Downpoint if (x >=downpoint.x && y >= downpoint.y) {box.x = Downpoint.x;box.y = Downpoint.y;box.width = X-downpoint.x;box.height = Y-downpoint.y;} Move the mouse to the upper-right corner of the Downpoint if (x >= downpoint.x && y <= downpoint.y) {box.x = downpoint.x;box.y = Y;box.width = X -downpoint.x;box.height = downpoint.y-y;}  Move the mouse to the upper-left corner of the Downpoint if (x <= downpoint.x && y <= downpoint.y) {box.x = x;box.y = Y;box.width = Downpoint.x- X;box.height = downpoint.y-y;} Move the mouse to the lower-left corner of the Downpoint if (x <= downpoint.x && y >= downpoint.y) {box.x = X;BOX.Y = Downpoint.y;box.width = Dow Npoint.x-x;box.height = Y-downpoint.y;}} Break;case cv_event_lbuttondown://Press the mouse to indicate that the rectangle can be started Drawing_box = true;//record Start Downpoint = Point (x, y); Break;case cv_ event_lbuttonup://release the mouse, representing the end of the draw rectangle Drawing_box = False;gotbox = True;break;default:break;}}              int main (int argc,char*argv[]) {//Read videocapture video (argv[1]);         Determine if the video is turned on if (!video.isopened ()) return 0;              The first frame of the video is Mat firstframe;         Mat frame; Read videoThe first frame of video>>frame;              Copy to Firstframe Frame.copyto (firstframe);       Register Namedwindow ("video", 1);             Setmousecallback ("video", Mouserecthandler,null);           Draw the area of interest while (!gotbox) {Firstframe.copyto (frame);           Rectangle (Frame,box,scalar (255,0,0), 2);//Draw an area of interest imshow ("video", frame);       if (waitkey () = = ' Q ')//---------very important break;              }//remove callback Setmousecallback ("video", Null,null);       Video continues for (;;)  {//Read video video>>frame;  Determines if there is a current frame if (!frame.data) break;          Draw the area of interest rectangle (Frame,box,scalar (255,255,0), 2);            Imshow ("video", frame);       if (waitkey) = = ' Q ') break;   } return 0;   }

"Results display":

Second case: Without affecting the video playback, draw the area of interest

#include <opencv2\core\core.hpp> #include <opencv2\highgui\highgui.hpp> #include <opencv2\imgproc\ Imgproc.hpp>using namespace CV; #include <iostream> #include <vector>using namespace std;/*---- Define mouse events-Draw rectangular areas: function as two headlights----*///first step: global variable bool Drawing_box = False;bool Gotbox = false; Rect box; Point downpoint;/*void mouserecthandler (int event, int x, int y, int. flags, void *param) {switch (event) {case cv_event_mous Emove:if (drawing_box) {box.width = X-box.x;box.height = y-box.y;} Break;case Cv_event_lbuttondown:drawing_box = True;box = Rect (x, y, 0, 0); Break;case cv_event_lbuttonup:drawing_box = Fal Se;gotbox = true;if (Box.width < 0) {box.x + = Box.width;box.width *=-1;} if (Box.height < 0) {box.y + = Box.height;box.height *=-1;} Break;default:break;}} */void Mouserecthandler (int event, int x, int y, int flags, void *param) {switch (event) {Case Cv_event_mousemove:if (Drawin G_box) {//The mouse moves to the lower-right corner of Downpoint if (x >=downpoint.x && y >= downpoint.y) {box.x = Downpoint.x;box.y = Downpoint.y;box.width = X-downpoint.x;box.height = Y-downpoint.y;} Move the mouse to the upper-right corner of the Downpoint if (x >= downpoint.x && y <= downpoint.y) {box.x = downpoint.x;box.y = Y;box.width = X -downpoint.x;box.height = downpoint.y-y;}  Move the mouse to the upper-left corner of the Downpoint if (x <= downpoint.x && y <= downpoint.y) {box.x = x;box.y = Y;box.width = Downpoint.x- X;box.height = downpoint.y-y;} Move the mouse to the lower-left corner of the Downpoint if (x <= downpoint.x && y >= downpoint.y) {box.x = X;BOX.Y = Downpoint.y;box.width = Dow Npoint.x-x;box.height = Y-downpoint.y;}} Break;case cv_event_lbuttondown://Press the mouse to indicate that the rectangle can be started Drawing_box = true;//record Start Downpoint = Point (x, y); Break;case cv_ event_lbuttonup://release the mouse, representing the end of the draw rectangle Drawing_box = False;gotbox = True;break;default:break;}}              int main (int argc,char*argv[]) {//Read videocapture video (argv[1]);        Determine if the video is turned on if (!video.isopened ()) return 0;         Video frame Mat frame; Register Namedwindow ("video", 1);             Setmousecallback ("video", Mouserecthandler,null);       Draw an area of interest for (;;)         {//Read the first frame of the video video>>frame;if (!frame.data) break; Rectangle (Frame,box,scalar (255,255,0), 2);//Draw an area of interest  Imshow ("video", frame);         if (gotbox) break;       if (waitkey () = = ' Q ')//---------very important break;              }//remove callback Setmousecallback ("video", Null,null);       Video continues for (;;)  {//Read video video>>frame;  Determines if there is a current frame if (!frame.data) break;          Draw the area of interest rectangle (Frame,box,scalar (0,255,0), 2);            Imshow ("video", frame);       if (waitkey) = = ' Q ') break;   } return 0;   }

Results

As for the difference between the two, try it out!

opencv-Video Processing-draw area of interest (ROI)