cvCaptureFromCAM没有加载任何帧

Question

我试图使用opencv实现人脸检测，使用http://opencv.willowgarage.com中给出的示例代码，但cvCaptureFromCAM不加载任何帧来自网络摄像头。我得到一个窗口对话框来选择我的摄像头，但它没有加载任何帧。

  #include "opencv2/objdetect/objdetect.hpp"
  #include "opencv2/highgui/highgui.hpp"
  #include "opencv2/imgproc/imgproc.hpp"
  #include <opencv/cv.h>
  #include <iostream>
  #include <stdio.h>
   using namespace std;
   using namespace cv;
  /** Function Headers */
void detectAndDisplay( Mat frame );
 /** Global variables */
String face_cascade_name = "haarcascade_frontalface_alt.xml";
String eyes_cascade_name = "haarcascade_eye_tree_eyeglasses.xml";
CascadeClassifier face_cascade;
CascadeClassifier eyes_cascade;
string window_name = "Capture - Face detection";
RNG rng(12345);
/** @function main */
int main( int argc, const char** argv )
{
CvCapture* capture;
Mat frame;
  //-- 1. Load the cascades
 if( !face_cascade.load( face_cascade_name ) ){ printf("--(!)Error loadingn"); return           -1; };
if( !eyes_cascade.load( eyes_cascade_name ) ){ printf("--(!)Error loadingn"); return  -1; };
 //-- 2. Read the video stream
 capture = cvCaptureFromCAM( -1 );
  if( capture )
  {
   while( true )
   {
     cout<<"hello";
  frame = cvQueryFrame( capture );
   //-- 3. Apply the classifier to the frame
   if( !frame.empty() )
  { detectAndDisplay( frame ); }
  else
  { printf(" --(!) No captured frame -- Break!"); break; }
  int c = waitKey(10);
  if( (char)c == 'c' ) { break; }
   }
   }
   else
   {cout<<"noframe";}
   return 0;
   }
    /** @function detectAndDisplay */
   void detectAndDisplay( Mat frame )
     {
   std::vector<Rect> faces;
   Mat frame_gray;
   cvtColor( frame, frame_gray, CV_BGR2GRAY );
   equalizeHist( frame_gray, frame_gray );
  //-- Detect faces
   face_cascade.detectMultiScale( frame_gray, faces, 1.1, 2, 0|CV_HAAR_SCALE_IMAGE,        Size(30, 30) );
  for( int i = 0; i < faces.size(); i++ )
 {
  Point center( faces[i].x + faces[i].width*0.5, faces[i].y + faces[i].height*0.5 );
  ellipse( frame, center, Size( faces[i].width*0.5, faces[i].height*0.5), 0, 0, 360,  Scalar( 255, 0, 255 ), 4, 8, 0 );
 Mat faceROI = frame_gray( faces[i] );
 std::vector<Rect> eyes;
 //-- In each face, detect eyes
  eyes_cascade.detectMultiScale( faceROI, eyes, 1.1, 2, 0 |CV_HAAR_SCALE_IMAGE, Size(30, 30) );
  for( int j = 0; j < eyes.size(); j++ )
  {
  Point center( faces[i].x + eyes[j].x + eyes[j].width*0.5, faces[i].y + eyes[j].y + eyes[j].height*0.5 );
   int radius = cvRound( (eyes[j].width + eyes[j].height)*0.25 );
  circle( frame, center, radius, Scalar( 255, 0, 0 ), 4, 8, 0 );
  }
  }
  //-- Show what you got
  imshow( window_name, frame );
   }

但是我的程序只打印noframe..我正在使用qtcreator

Answer 1

我已经测试了你的程序，但它在我的电脑上工作。看起来你的摄像头没有通过帧。你确定你的摄像头工作正常吗?

Answer 2

我做了以下更改，它为我工作:

capture = cvCaptureFromCAM( 0 );