OpenCV对象检测教程 [英] OpenCV Object detection tutorial

问题描述

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).但是我遇到了涉及haarcascade的代码的一些问题.代码可以完美构建，并且网络摄像头似乎可以闪烁并正常工作，但是代码显示空白窗口为已附加.

I'm new to OpenCV platform. I've installed and successfully run some tutorial codes(inbuilt). But I'm facing some issues with the codes involving haarcascade.The code builds perfectly and also the webcam seems to flash light and work but the code displays blank window as attached.image

有人可以建议对此问题进行一些纠正吗?

Can anyone suggest some rectification for the problem?

(我使用的是Opencv 3.0.0版和Visual Studios 2013.)

(I'm using opencv version 3.0.0 and 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 );
    }

推荐答案

我认为这是一个已知的错误

您可以尝试更新的代码(我通过注释指出了更改)

could you try my updated code ( i pointed out the changes by comments)

#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 );
}

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