violajones.cpp

这是个人脸识别程序

// $violajones.cpp 1.5 milbo$ interface to OpenCV Viola Jones face detector.
//
// TODO We re-open the Img in fViolaJonesFindFace, rather than using the
// passed-in Img parameter.  This wastes a bit of time and could  be fixed.
//-----------------------------------------------------------------------------
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// A copy of the GNU General Public License is available at
// http://www.r-project.org/Licenses/
//-----------------------------------------------------------------------------

#include "all.hpp"
#include "cv.h"
#include "highgui.h"

// accurate but slow: these values are recommended in opencvref_cv.htm
static const double SCALE_FACTOR   = 1.1;
static const int    MIN_NEIGHBORS  = 3;
static const int    DETECTOR_FLAGS = 0;

static const char *CASCADE_NAME = "haarcascade_frontalface_alt2.xml";

static CvHaarClassifierCascade *pgCascade;
static CvMemStorage *pgStorage;

//-----------------------------------------------------------------------------
// specifying a min face width helps reduce nbr of false positives

static int nMinFaceWidth (int ImageWidth)
{
return ImageWidth / 4;
}

//-----------------------------------------------------------------------------
void CloseViolaJones (void)
{
if (pgCascade)
    {
    cvReleaseHaarClassifierCascade(&pgCascade);
    cvReleaseMemStorage(&pgStorage);
    pgCascade = NULL;
    }
}

//-----------------------------------------------------------------------------
static void OpenViolaJones (const char sDataDir[])
{
char sCascadePath[SLEN];
sprintf(sCascadePath, "%s/%s", sDataDir, CASCADE_NAME);
pgCascade = (CvHaarClassifierCascade*)cvLoad(sCascadePath, 0, 0, 0);
if(!pgCascade)
    Err("Can't load %s", sCascadePath);
pgStorage = cvCreateMemStorage(0);
if (!pgStorage)
    Err("Out of memory (cvCreateMemStorage failed)");
}

//-----------------------------------------------------------------------------
// Returns with face position in Shape.
// Face is a "ViolaJones global detector shape", with NBR_VIOLA_JONES_POINTS points.
// See DETECTOR_ defs in landmarks.hpp for point names.
// If it can't find a face (with two eyes), we exit with an error message.

bool fViolaJonesFindFace(SHAPE &Shape,       // out
        Image &Img,                         // in: TODO not actually used
        const char sImageFile[],            // in
        const char sDataDir[])              // in
{
if (!pgCascade) // first time?
    OpenViolaJones(sDataDir);
cvClearMemStorage(pgStorage);
Shape.dimClear(NBR_VIOLA_JONES_POINTS, 2);

IplImage* pImage = cvLoadImage(sImageFile, 1);
if (!pImage)
    Err("Can't load %s", sImageFile);

IplImage* pWork = cvCreateImage(cvSize(pImage->width, pImage->height), 8, 1);
cvCvtColor(pImage, pWork, CV_BGR2GRAY);
cvResize(pWork, pWork, CV_INTER_LINEAR);
cvEqualizeHist(pWork, pWork);

CvSeq* pFaces = cvHaarDetectObjects(pWork, pgCascade, pgStorage,
                    SCALE_FACTOR, MIN_NEIGHBORS, DETECTOR_FLAGS,
                    cvSize(nMinFaceWidth(pImage->width), nMinFaceWidth(pImage->width)));

cvReleaseImage(&pWork);

if (pFaces == NULL)     // should never happen
    {
    cvReleaseImage(&pImage);
    Err("cvHaarDetectObjects failed");
    }
int iSelectedFace = 0;

// get most central face

double MaxOffset = 1e10;    // max abs dist from center of face to center of image
for (int iFace = 0; iFace < pFaces->total; iFace++)
    {
    CvRect* r = (CvRect*)cvGetSeqElem(pFaces, iFace);
    double Offset = ABS(r->x + r->width/2.0 - pImage->width/2.0);
    if (Offset < MaxOffset)
        {
        MaxOffset = Offset;
        iSelectedFace = iFace;
        }
    }
if (pFaces->total < 1)
	{
    lprintf("\nViola Jones detector found no faces in %s\n", sImageFile);
	return false;
	}
// Write the global detector shape into Shape.
// We must convert the Viola Jones shape coords to our internal shape coords.

CvRect* r = (CvRect*)cvGetSeqElem(pFaces, iSelectedFace);
Shape(DETECTOR_TopLeft, VX)  = r->x - pImage->width/2.0;
Shape(DETECTOR_TopLeft, VY)  = pImage->height/2.0 - r->y;
Shape(DETECTOR_BotRight, VX) = Shape(DETECTOR_TopLeft, VX) + r->width;
Shape(DETECTOR_BotRight, VY) = Shape(DETECTOR_TopLeft, VY) - r->height;

cvReleaseImage(&pImage);
return true;
}