c++ - can't read from the webcam -


for strange reasons, program fails read frame webcam. opens webcam though. i've searched problem , found out variety of solutions none of them worked me. code 

#include <iostream> #include <cstdlib> #include "opencv2/core/core.hpp" #include "opencv2/highgui/highgui.hpp"  int main() {     // access default webcam      cv::videocapture cap(0);       // double check webcam before start reading.      if ( !cap.isopened() ){          std::cerr  << "cannot open webcam " << std::endl;         exit (exit_failure);     }      cv::mat frame;     cv::namedwindow("webcam",cv_window_autosize);      while ( true ){         // acquire frame         cap >> frame;         // safety checking         if ( !frame.data ){           std::cerr << "cannot acquire frame webcam " << std::endl;             break;        }         cv::imshow("webcam", frame);          if ( cv::waitkey(30) == 27){         std::cout << "esc key pressed" << std::endl;         break;         }     }      return 0; }

and window before terminating program.

enter image description here

i'm using windows 7 ( dell laptop ). code compiled in release mode linking against .dlls. opencv version 2.4.10. in commmand prompt 

cl /ehsc main.cpp /fetest.exe /i d:\cpp_libraries\opencv_2.4.10\build\include /link /libpath:d:\cpp_libraries\opencv_2.4.10\build\x86\vc12\lib opencv_core2410.lib opencv_highgui2410.lib

i have run same code in ubuntu (dual boot alongside windows 7) , opens webcam not through highgui , got error 

highgui error: v4l/v4l2: vidioc_s_crop init done  opengl support available

any suggestions regarding matter. after diggings, some ppl pointed out cmake, therefore need reinstall opencv , configure cmake properly. there solutions problem without reinstall library if problem both ubuntu , windows ?

follow opencv documentation videocapture heure : videocapture. provides simple example video capturing in c++.

there differences code, on mat frame inside loop.


Comments

Post a Comment

Popular posts from this blog

php - failed to open stream: HTTP request failed! HTTP/1.0 400 Bad Request -

this code i'm using find latitude , longitude of place: function coords($address){ echo $url="http://maps.googleapis.com/maps/api/geocode/json?address=".$address; $json = file_get_contents(urlencode($url)); $data = json_decode($json, true); print_r($data['results'][0]['geometry']['location']['lat']); print_r($data['results'][0]['geometry']['location']['lng']); } however returns warning: failed open stream: http request failed! http/1.0 400 bad request if use above code in simple procedure works fine not in function. note: have tried curl_init()... method produced same result? instead of encoding whole url encode address part. following code work fine $add='jamshoro phase 2'; $url="http://maps.googleapis.com/maps/api/geocode/json?address=".urlencode($add); $json = file_get_contents($url); $data = json_decode($json, true); print_r($data['r
Read more

java - How to filter a backspace keyboard input -

i have code gives message when key number pressed: txtvalueofclause.addeventfilter(keyevent.key_typed, new eventhandler<keyevent>() { @override public void handle(keyevent t) { char ar[] = t.getcharacter().tochararray(); char ch = ar[t.getcharacter().tochararray().length - 1]; if (!(ch >= '0' && ch <= '9')) { system.out.println("the char entered not number"); t.consume(); } } }); now if press on wrong button , press backspace remove it, error message. how can add backspace input if statement? i have found answer: txtvalueofclause.addeventfilter(keyevent.key_typed, new eventhandler<keyevent>() { @override public void handle(keyevent t) { char ar[] = t.getcharacter().tochararray(); char ch = ar[t.getcharacter().tochar
Read more

java - Show Soft Keyboard when EditText Appears -

i have code in android app, alert dialog , keyboard, , when dialog shown want keyboard appear. not , not sure why? here code: final alertdialog.builder alert = new alertdialog.builder(this); alert.settitle("title"); alert.setmessage("message"); final edittext input = new edittext(this); input.setinputtype(inputtype.type_class_number); alert.setview(input); input.setonfocuschangelistener(new view.onfocuschangelistener() { @override public void onfocuschange(view v, boolean hasfocus) { if (hasfocus) { log.i(tag, "in focus"); inputmethodmanager inputmethodmanager = (inputmethodmanager) getsystemservice(context.input_method_service); inputmethodmanager.showsoftinput(input, inputmethodmanager.show_implicit); } } }); but keyboard not appear though edit text in focus, , tell appear why, doesn't come up? thanks in advance.
Read more