OpenCV 对象检测教程

Question

我是 OpenCV 平台的新手。我已经安装并成功运行了一些教程代码（内置）。但我在涉及 haarcascade 的代码方面遇到了一些问题。代码构建完美，网络摄像头似乎闪烁并工作，但代码显示附加的空白窗口。image

任何人都可以提出一些纠正这个问题的建议吗？

（我使用的是 opencv 3.0.0 版和 Visual Studios 2013。）

    #include "stdafx.h"
    #include "opencv2/objdetect.hpp"
    #include "opencv2/videoio.hpp"
    #include "opencv2/highgui.hpp"
    #include "opencv2/imgproc.hpp"

    #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";

   /** @function main */
   int main( void )
    {
    VideoCapture capture;
Mat frame;

//-- 1. Load the cascades
if( !face_cascade.load( face_cascade_name ) ){ printf("--(!)Error loading face cascade\n"); return -1; };
if( !eyes_cascade.load( eyes_cascade_name ) ){ printf("--(!)Error loading eyes cascade\n"); return -1; };

//-- 2. Read the video stream
capture.open( -1 );
if ( ! capture.isOpened() ) { printf("--(!)Error opening video capture\n"); return -1; }

while ( capture.read(frame) )
{
    if( frame.empty() )
    {
        printf(" --(!) No captured frame -- Break!");
        break;
    }

    //-- 3. Apply the classifier to the frame
    detectAndDisplay( frame );

    int c = waitKey(10);
    if( (char)c == 27 ) { break; } // escape
}
return 0;
    }

    /** @function detectAndDisplay */
    void detectAndDisplay( Mat frame )
   {
        std::vector<Rect> faces;
Mat frame_gray;

cvtColor( frame, frame_gray, COLOR_BGR2GRAY );
equalizeHist( frame_gray, frame_gray );

//-- Detect faces
face_cascade.detectMultiScale( frame_gray, faces, 1.1, 2, 0|CASCADE_SCALE_IMAGE, Size(30, 30) );

for ( size_t i = 0; i < faces.size(); i++ )
{
    Point center( faces[i].x + faces[i].width/2, faces[i].y + faces[i].height/2 );
    ellipse( frame, center, Size( faces[i].width/2, faces[i].height/2 ), 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 |CASCADE_SCALE_IMAGE, Size(30, 30) );

    for ( size_t j = 0; j < eyes.size(); j++ )
    {
        Point eye_center( faces[i].x + eyes[j].x + eyes[j].width/2, faces[i].y + eyes[j].y + eyes[j].height/2 );
        int radius = cvRound( (eyes[j].width + eyes[j].height)*0.25 );
        circle( frame, eye_center, radius, Scalar( 255, 0, 0 ), 4, 8, 0 );
    }
}
//-- Show what you got
imshow( window_name, frame );
    }

Answer 1

我认为是a known bug

你能试试我更新的代码吗（我指出了 cmets 的变化）

#include "opencv2/objdetect.hpp"
#include "opencv2/videoio.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"
#include <opencv2/core/ocl.hpp> // additional header ************************

#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";

/** @function main */
int main( void )
{
    ocl::setUseOpenCL(false); // disable OpenCL *******************
    VideoCapture capture;
    Mat frame;

    //-- 1. Load the cascades
    if( !face_cascade.load( face_cascade_name ) ){ printf("--(!)Error loading face cascade\n"); return -1; };
    if( !eyes_cascade.load( eyes_cascade_name ) ){ printf("--(!)Error loading eyes cascade\n"); return -1; };

    //-- 2. Read the video stream
    capture.open( 0 ); // Open webcam 0 ***************************
    if ( ! capture.isOpened() ) { printf("--(!)Error opening video capture\n"); return -1; }

    while ( capture.read(frame) )
    {
        if( frame.empty() )
        {
            printf(" --(!) No captured frame -- Break!");
            break;
        }

        //-- 3. Apply the classifier to the frame
        detectAndDisplay( frame );

        int c = waitKey(10);
        if( (char)c == 27 ) { break; } // escape
    }
    return 0;
}

/** @function detectAndDisplay */
void detectAndDisplay( Mat frame )
{
    std::vector<Rect> faces;
    Mat frame_gray;

    cvtColor( frame, frame_gray, COLOR_BGR2GRAY );
    equalizeHist( frame_gray, frame_gray );

    //-- Detect faces
    face_cascade.detectMultiScale( frame_gray, faces, 1.1, 2, 0|CASCADE_SCALE_IMAGE, Size(30, 30) );

    for ( size_t i = 0; i < faces.size(); i++ )
    {
        Point center( faces[i].x + faces[i].width/2, faces[i].y + faces[i].height/2 );
        ellipse( frame, center, Size( faces[i].width/2, faces[i].height/2 ), 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 |CASCADE_SCALE_IMAGE, Size(30, 30) );

        for ( size_t j = 0; j < eyes.size(); j++ )
        {
            Point eye_center( faces[i].x + eyes[j].x + eyes[j].width/2, faces[i].y + eyes[j].y + eyes[j].height/2 );
            int radius = cvRound( (eyes[j].width + eyes[j].height)*0.25 );
            circle( frame, eye_center, radius, Scalar( 255, 0, 0 ), 4, 8, 0 );
        }
    }
    //-- Show what you got
    imshow( window_name, frame );
}