c++ - Calculate the distance to a red point with opencv -


i'm newbie opencv. managed install , set visual 2013. tested sample of live stream laptop's camera , works. want calculate distance webcam red laser spot in middle of screen(live_stream). tell me can start? know must find r(red) pixel middle of screen dont know how , functions can use. help, please? live stream webcam works shown below:

   #include "opencv2/highgui/highgui.hpp"    #include <opencv2/objdetect/objdetect.hpp>    #include <opencv2/imgproc/imgproc.hpp>    #include <iostream>    #include <vector>    #include <stdio.h>   int main()  {   //data structure store cam.  cvcapture* cap=cvcreatecameracapture(0);  //image variable store frame  iplimage* frame;  //window show livefeed  cvnamedwindow("imagine live",cv_window_autosize);  while(1) { //load next frame frame=cvqueryframe(cap); //if frame not loaded break loop if(!frame)     printf("\nno");; //show present frame cvshowimage("imagine live",frame); //escape sequence char c=cvwaitkey(33); //if key pressed user esc(ascii 27) break out of loop if(c==27)    break; } //cleanup cvreleasecapture(&cap); cvdestroyallwindows(); }

your red dot going show total white in camera stream, suggest

  1. convert grayscale using cvtcolor().
  2. threshold using threshold(), parameters use thresh=253, maxval=255 , mode thresh_binary. should give image black small white dot laser is.
  3. then can use findcontours() locate dot in image. boundingrect() of contour , can calculate center precise coordinates of dot.

also has been mentioned, not use deprecated c api, use c++ api instead.


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