qml+opencv(二)

实现人脸检测。opencv提供了Haar分类器，其在data文件下还提供了训练的数据，所以实现这个不是很难。
我继承OpenCVaction，实现了人脸检测的算法。

#ifndef OPENCVFACEDETECTACTION_H#define OPENCVFACEDETECTACTION_H#include "opencvaction.h"class OpenCVfaceDetectAction : public OpenCVaction{    Q_OBJECTpublic:    OpenCVfaceDetectAction(QObject *parent = 0);    ~OpenCVfaceDetectAction();    void action(IplImage *imgin, IplImage *&imgout);signals:    void a();private:    CvHaarClassifierCascade* m_cascade;    CvMemStorage* m_storage;    double m_scale;};#endif // OPENCVFACEDETECTACTION_H#include "opencvfacedetectaction.h"#include <QDebug>const char* cascade_name = "data/haarcascade_frontalface_alt.xml";OpenCVfaceDetectAction::OpenCVfaceDetectAction(QObject *parent): OpenCVaction(parent),    m_cascade(NULL),    m_storage(NULL),    m_scale(1.3){    m_cascade = (CvHaarClassifierCascade*)cvLoad(cascade_name, 0, 0, 0);    if (!m_cascade) {        qDebug() << "load Cascade fail!";    }    m_storage = cvCreateMemStorage(0);}OpenCVfaceDetectAction::~OpenCVfaceDetectAction(){    if (m_cascade) {        cvReleaseHaarClassifierCascade(&m_cascade);    }    cvReleaseMemStorage(&m_storage);}void OpenCVfaceDetectAction::action(IplImage *imgin, IplImage *&imgout){    imgout = cvCloneImage(imgin);    if (!m_cascade) {        qDebug() << "Cascade is invaild!";        return;    }    static CvScalar color = CV_RGB(255, 255, 255);    //Image Preparation    //    IplImage* gray = cvCreateImage(cvGetSize(imgin), 8, 1);    IplImage* small_img = cvCreateImage(cvSize(cvRound(imgin->width / m_scale),                                               cvRound(imgin->height / m_scale)), 8, 1);    cvCvtColor(imgin, gray, CV_BGR2GRAY);    cvResize(gray, small_img, CV_INTER_LINEAR);    cvEqualizeHist(small_img, small_img); //直方图均衡    //Detect objects if any    //    cvClearMemStorage(m_storage);    double t = (double)cvGetTickCount();    CvSeq *objects = cvHaarDetectObjects(small_img,                                         m_cascade,                                         m_storage,                                         1.1,                                         2,                                         0,                                         cvSize(50,50));    t = (double)cvGetTickCount() - t;    qDebug() << "detection time =" << t / ((double)cvGetTickFrequency()*1000.) << "ms";    //Loop through found objects and draw boxes around them    for(int i=0; i < (objects ? objects->total : 0); ++i)    {        CvRect* r = (CvRect*)cvGetSeqElem(objects, i);        cvRectangle(imgout, cvPoint(r->x * m_scale, r->y * m_scale),                    cvPoint((r->x + r->width) * m_scale, (r->y + r->height) * m_scale), color, 2, CV_AA);    }    cvReleaseImage(&gray);    cvReleaseImage(&small_img);    emit a();}

在OpenCVshowFrame中，添加下面

  OpenCVfaceDetectAction *f = new OpenCVfaceDetectAction();  m_actions.push_back(f);

就ok了。
运行效果如下：