关键词：
在AI技术发展迅猛的今天，很多设备都希望加上人脸识别功能，好像不加上点人脸识别功能感觉不够高大上，都往人脸识别这边靠，手机刷脸解锁，刷脸支付，刷脸开门，刷脸金融，刷脸安防，是不是以后还可以刷脸匹配男女交友？
很多人认为人脸识别直接用opencv做，其实那只是极其基础的识别个人脸，然并卵，好比学C++写了个hello类似。拿到人脸区域图片只是万里长征的第一步，真正能够起作用的是人脸特征值的提取，然后用于搜索和查找人脸，比如两张图片比较相似度，从一堆人脸库中找到最相似的人脸，对当前人脸识别是否是活体等。
对于可以接入外网的设备，可以直接通过在线api的http请求方式获得结果，但是有很多应用场景是离线的，或者说不通外网，只能局域网使用，为了安全性考虑，这个时候就要求所有的人脸处理在本地完成，本篇文章采用的百度离线SDK作为解决方案。可以去官网申请，默认有6个免费的密钥使用三个月，需要与本地设备的指纹信息匹配，感兴趣的同学可以自行去官网下载SDK。
百度离线人脸识别SDK文件比较大，光模型文件就645MB，估计这也许是识别率比较高的一方面原因吧，不断训练得出的模型库，本篇文章只放出Qt封装部分源码。官网对应的使用说明还是非常详细的，只要是学过编程的人就可以看懂。
第一步：初始化SDK
第二步：执行动作，比如查找人脸、图片比对、特征值比对等
完整头文件代码：
#ifndef FACEBAIDULOCAL_H
#define FACEBAIDULOCAL_H
/**
* 百度离线版人脸识别+人脸比对等功能类 作者:feiyangqingyun(QQ:517216493) 2018-8-30
* 1:支持活体检测
* 2:可设置最大队列中的图片数量
* 3:多线程处理,通过type控制当前处理类型
* 4:支持单张图片检索相似度最高的图片
* 5:支持指定目录图片生成特征文件
* 6:支持两张图片比对方式
* 7:可设置是否快速查找
* 8:可设置是否统计用时
*/
#include <QtCore>
#include <QtGui>
#if (QT_VERSION > QT_VERSION_CHECK(5,0,0))
#include <QtWidgets>
#endif
#include "baidu_face_api.h"
class FaceBaiDuLocal : public QThread
Q_OBJECT
public:
static FaceBaiDuLocal *Instance();
explicit FaceBaiDuLocal(QObject *parent = 0);
~FaceBaiDuLocal();
protected:
void run();
private:
static QScopedPointer<FaceBaiDuLocal> self;
BaiduFaceApi *api;
std::vector<TrackFaceInfo> *faces;
QMutex mutex; //锁对象
bool stopped; //线程停止标志位
int maxCount; //最大图片张数
int type; //当前处理类型
int percent; //最小人脸百分比
int delayms; //减去毫秒数,用于造假
bool findFast; //是否快速模式
bool countTime; //统计用时
bool busy; //是否正忙
QList<QString> flags; //等待处理的图像队列的名称
QList<QImage> imgs; //等待处理的图像队列
QList<QImage> imgs2; //等待处理的比对图像队列
QString sdkPath; //SDK目录
QString imgDir; //图片目录
QImage oneImg; //单张图片比对找出最大特征图像
QList<QString> imgNames; //图像队列
QList<QList<float> > features; //特征队列
signals:
//人脸区域坐标返回
void receiveFaceRect(const QString &flag, const QRect &rect, int msec);
//获取人脸区域坐标失败
void receiveFaceRectFail(const QString &flag);
//人脸特征返回
void receiveFaceFeature(const QString &flag, const QList<float> &feature, int msec);
//获取人脸特征失败
void receiveFaceFeatureFail(const QString &flag);
//人脸比对结果返回
void receiveFaceCompare(const QString &flag, float result, int msec);
//人脸比对失败
void receiveFaceCompareFail(const QString &flag);
//单张图片检索最大相似度结果返回
void receiveFaceCompareOne(const QString &flag, const QImage &srcImg, const QString &targetName, float result);
//所有人脸特征提取完毕
void receiveFaceFeatureFinsh();
//活体检测返回
void receiveFaceLive(const QString &flag, float result, int msec);
//活体检测失败
void receiveFaceLiveFail(const QString &flag);
public slots:
//初始化SDK
void init();
//停止处理线程
void stop();
//获取当前是否忙
bool getBusy();
//设置图片队列最大张数
void setMaxCount(int maxCount);
//设置当前处理类型
void setType(int type);
//设置最小人脸百分比
void setPercent(int percent);
//设置减去毫秒数
void setDelayms(int delayms);
//设置是否快速模式
void setFindFast(bool findFast);
//设置是否统计用时
void setCountTime(bool countTime);
//设置是否忙
void setBusy(bool busy);
//设置SDK目录
void setSDKPath(const QString &sdkPath);
//设置要将图片提取出特征的目录
void setImgDir(const QString &imgDir);
//设置单张需要检索的图片
void setOneImg(const QString &flag, const QImage &oneImg);
//往队列中追加单张图片等待处理
void append(const QString &flag, const QImage &img);
//往队列中追加两张图片等待比对
void append(const QString &flag, const QImage &img, const QImage &img2);
//自动加载目录下的所有图片的特征
void getFaceFeatures(const QString &imgDir);
//获取人脸区域
bool getFaceRect(const QString &flag, const QImage &img, QRect &rect, int &msec);
//活体检测
bool getFaceLive(const QString &flag, const QImage &img, float &result, int &msec);
//获取人脸特征
bool getFaceFeature(const QString &flag, const QImage &img, QList<float> &feature, int &msec);
//人脸比对,传入两张照片特征
float getFaceCompare(const QString &flag, const QList<float> &feature1, const QList<float> &feature2);
//人脸比对,传入两张照片
bool getFaceCompare(const QString &flag, const QImage &img1, const QImage &img2, float &result, int &msec);
//从一堆图片中找到最像的一张图片
void getFaceOne(const QString &flag, const QImage &img, QString &targetName, float &result);
//指定特征找到照片
void getFaceOne(const QString &flag, const QList<float> &feature, QString &targetName, float &result);
//添加人脸
void appendFace(const QString &flag, const QImage &img, const QString &txtFile);
//删除人脸
void deleteFace(const QString &flag);
;
#endif // FACEBAIDULOCAL_H
完整实现文件代码：
#include "facebaidulocal.h"
#define TIMEMS qPrintable(QTime::currentTime().toString("HH:mm:ss zzz"))
QByteArray getImageData(const QImage &image)
QByteArray imageData;
QBuffer buffer(&imageData);
image.save(&buffer, "JPG");
imageData = imageData.toBase64();
return imageData;
QScopedPointer<FaceBaiDuLocal> FaceBaiDuLocal::self;
FaceBaiDuLocal *FaceBaiDuLocal::Instance()
if (self.isNull())
QMutex mutex;
QMutexLocker locker(&mutex);
if (self.isNull())
self.reset(new FaceBaiDuLocal);
return self.data();
FaceBaiDuLocal::FaceBaiDuLocal(QObject *parent) : QThread(parent)
//注册信号中未知的数据类型
qRegisterMetaType<QList<float> >("QList<float>");
stopped = false;
maxCount = 100;
type = 1;
percent = 8;
delayms = 0;
findFast = false;
countTime = true;
busy = false;
sdkPath = qApp->applicationDirPath() + "/facesdk";
imgDir = "";
oneImg = QImage();
api = new BaiduFaceApi;
faces = new std::vector<TrackFaceInfo>();
FaceBaiDuLocal::~FaceBaiDuLocal()
delete api;
this->stop();
this->wait(1000);
void FaceBaiDuLocal::run()
this->init();
while(!stopped)
int count = flags.count();
if (count > 0)
QMutexLocker lock(&mutex);
busy = true;
if (type == 0)
QString flag = flags.takeFirst();
QImage img = imgs.takeFirst();
QRect rect;
int msec;
if (getFaceRect(flag, img, rect, msec))
emit receiveFaceRect(flag, rect, msec);
else
emit receiveFaceRectFail(flag);
else if (type == 1)
QString flag = flags.takeFirst();
QImage img = imgs.takeFirst();
QList<float> feature;
int msec;
if (getFaceFeature(flag, img, feature, msec))
emit receiveFaceFeature(flag, feature, msec);
else
emit receiveFaceFeatureFail(flag);
else if (type == 2)
QString flag = flags.takeFirst();
QImage img1 = imgs.takeFirst();
QImage img2 = imgs2.takeFirst();
float result;
int msec;
if (getFaceCompare(flag, img1, img2, result, msec))
emit receiveFaceCompare(flag, result, msec);
else
emit receiveFaceCompareFail(flag);
else if (type == 3)
flags.takeFirst();
getFaceFeatures(imgDir);
else if (type == 4)
QString flag = flags.takeFirst();
QString targetName;
float result;
getFaceOne(flag, oneImg, targetName, result);
if (!targetName.isEmpty())
emit receiveFaceCompareOne(flag, oneImg, targetName, result);
else if (type == 5)
QString flag = flags.takeFirst();
QImage img = imgs.takeFirst();
float result;
int msec;
if (getFaceLive(flag, img, result, msec))
emit receiveFaceLive(flag, result, msec);
else
emit receiveFaceLiveFail(flag);
msleep(100);
busy = false;
stopped = false;
void FaceBaiDuLocal::init()
int res = api->sdk_init();
res = api->is_auth();
if(res != 1)
qDebug() << TIMEMS << QString("init sdk error: %1").arg(res);
return;
else
//设置最小人脸,默认30
api->set_min_face_size(percent);
//设置光照阈值,默认40
api->set_illum_thr(20);
//设置角度阈值,默认15
//api->set_eulur_angle_thr(30, 30, 30);
qDebug() << TIMEMS << "init sdk ok";
void FaceBaiDuLocal::stop()
stopped = true;
bool FaceBaiDuLocal::getBusy()
return this->busy;
void FaceBaiDuLocal::setMaxCount(int maxCount)
if (maxCount <= 1000)
this->maxCount = maxCount;
void FaceBaiDuLocal::setType(int type)
if (this->type != type)
this->type = type;
this->flags.clear();
this->imgs.clear();
this->imgs2.clear();
void FaceBaiDuLocal::setPercent(int percent)
this->percent = percent;
void FaceBaiDuLocal::setDelayms(int delayms)
this->delayms = delayms;
void FaceBaiDuLocal::setFindFast(bool findFast)
this->findFast = findFast;
void FaceBaiDuLocal::setCountTime(bool countTime)
this->countTime = countTime;
void FaceBaiDuLocal::setBusy(bool busy)
this->busy = busy;
void FaceBaiDuLocal::setSDKPath(const QString &sdkPath)
this->sdkPath = sdkPath;
void FaceBaiDuLocal::setImgDir(const QString &imgDir)
this->imgDir = imgDir;
this->flags.clear();
this->flags.append("imgDir");
this->type = 3;
void FaceBaiDuLocal::setOneImg(const QString &flag, const QImage &oneImg)
setType(4);
//需要将图片重新拷贝一个,否则当原图像改变之后也会改变
this->oneImg = oneImg.copy();
this->flags.append(flag);
void FaceBaiDuLocal::append(const QString &flag, const QImage &img)
QMutexLocker lock(&mutex);
int count = flags.count();
if (count < maxCount)
flags.append(flag);
imgs.append(img);
void FaceBaiDuLocal::append(const QString &flag, const QImage &img, const QImage &img2)
QMutexLocker lock(&mutex);
int count = flags.count();
if (count < maxCount)
flags.append(flag);
imgs.append(img);
imgs2.append(img2);
void FaceBaiDuLocal::getFaceFeatures(const QString &imgDir)
imgNames.clear();
features.clear();
//载入指定目录图像处理特征
QDir imagePath(imgDir);
QStringList filter;
filter << "*.jpg" << "*.bmp" << "*.png" << "*.jpeg" << "*.gif";
imgNames.append(imagePath.entryList(filter));
qDebug() << TIMEMS << "getFaceFeatures" << imgNames;
//从目录下读取同名的txt文件(存储的特征)
//如果存在则从文件读取特征,如果不存在则转码解析出特征
//转码完成后将得到的特征存储到同名txt文件
int count = imgNames.count();
for (int i = 0; i < count; i++)
QList<float> feature;
int msec;
QString imgName = imgNames.at(i);
QStringList list = imgName.split(".");
QString txtName = imgDir + "/" + list.at(0) + ".txt";
QFile file(txtName);
if (file.exists())
if (file.open(QFile::ReadOnly))
QString data = file.readAll();
file.close();
qDebug() << TIMEMS << "readFaceFeature" << txtName;
QStringList list = data.split(",");
foreach (QString str, list)
if (!str.isEmpty())
feature.append(str.toFloat());
else
QImage img(imgDir + "/" + imgName);
bool ok = getFaceFeature(imgName, img, feature, msec);
if (ok)
emit receiveFaceFeature(imgName, feature, msec);
if (file.open(QFile::WriteOnly))
QStringList list;
foreach (float fea, feature)
list.append(QString::number(fea));
qDebug() << TIMEMS << "writeFaceFeature" << txtName;
file.write(list.join(",").toLatin1());
file.close();
features.append(feature);
msleep(1);
qDebug() << TIMEMS << "getFaceFeatures finsh";
emit receiveFaceFeatureFinsh();
bool FaceBaiDuLocal::getFaceRect(const QString &flag, const QImage &img, QRect &rect, int &msec)
//qDebug() << TIMEMS << flag << "getFaceRect";
QTime time;
if (countTime)
time.start();
faces->clear();
QByteArray imageData = getImageData(img);
int result = api->track_max_face(faces, imageData.constData(), 1);
if (result == 1)
TrackFaceInfo info = faces->at(0);
FaceInfo ibox = info.box;
float width = ibox.mWidth;
float x = ibox.mCenter_x;
float y = ibox.mCenter_y;
rect = QRect(x - width / 2, y - width / 2, width, width);
if (countTime)
msec = time.elapsed() - delayms;
else
msec = delayms;
msec = msec < 0 ? 0 : msec;
return true;
else
return false;
return false;
bool FaceBaiDuLocal::getFaceLive(const QString &flag, const QImage &img, float &result, int &msec)
//qDebug() << TIMEMS << flag << "getFaceLive";
QTime time;
if (countTime)
time.start();
result = 0;
QByteArray imageData = getImageData(img);
std::string value = api->rgb_liveness_check(imageData.constData(), 1);
QString data = value.c_str();
data = data.replace(" ", "");
data = data.replace(""", "");
data = data.replace(" ", "");
int index = -1;
QStringList list = data.split("
");
foreach (QString str, list)
index = str.indexOf("score:");
if (index >= 0)
result = str.mid(6, 4).toFloat();
break;
if (index >= 0)
if (countTime)
msec = time.elapsed() - delayms;
else
msec = delayms;
msec = msec < 0 ? 0 : msec;
return true;
else
return false;
return false;
bool FaceBaiDuLocal::getFaceFeature(const QString &flag, const QImage &img, QList<float> &feature, int &msec)
//qDebug() << TIMEMS << flag << "getFaceFeature" << img.width() << img.height() << img.size();
QTime time;
if (countTime)
time.start();
const float *fea = nullptr;
QByteArray imageData = getImageData(img);
int result = api->get_face_feature(imageData.constData(), 1, fea);
if (result == 512)
feature.clear();
for (int i = 0; i < 512; i++)
feature.append(fea[i]);
if (countTime)
msec = time.elapsed() - delayms;
else
msec = delayms;
msec = msec < 0 ? 0 : msec;
return true;
else
return false;
return false;
float FaceBaiDuLocal::getFaceCompare(const QString &flag, const QList<float> &feature1, const QList<float> &feature2)
//qDebug() << TIMEMS << flag << "getFaceCompareXXX";
std::vector<float> fea1, fea2;
for (int i = 0; i < 512; i++)
fea1.push_back(feature1.at(i));
fea2.push_back(feature2.at(i));
float result = api->compare_feature(fea1, fea2);
//过滤非法的值
result = result > 100 ? 0 : result;
return result;
bool FaceBaiDuLocal::getFaceCompare(const QString &flag, const QImage &img1, const QImage &img2, float &result, int &msec)
//qDebug() << TIMEMS << flag << "getFaceCompare";
result = 0;
bool ok1, ok2;
QList<float> feature1, feature2;
int msec1, msec2;
QString flag1, flag2;
if (flag.contains("|"))
QStringList list = flag.split("|");
flag1 = list.at(0);
flag2 = list.at(1);
else
flag1 = flag;
flag2 = flag;
QTime time;
if (countTime)
time.start();
ok1 = getFaceFeature(flag1, img1, feature1, msec1);
if (ok1)
emit receiveFaceFeature(flag1, feature1, msec1);
ok2 = getFaceFeature(flag2, img2, feature2, msec2);
if (ok2)
emit receiveFaceFeature(flag2, feature2, msec2);
if (ok1 && ok2)
result = getFaceCompare(flag, feature1, feature2);
if (countTime)
msec = time.elapsed() - delayms;
else
msec = delayms;
msec = msec < 0 ? 0 : msec;
return true;
else
return false;
return false;
void FaceBaiDuLocal::getFaceOne(const QString &flag, const QImage &img, QString &targetName, float &result)
QList<float> feature;
int msec;
bool ok = getFaceFeature(flag, img, feature, msec);
if (ok)
emit receiveFaceFeature(flag, feature, msec);
getFaceOne(flag, feature, targetName, result);
void FaceBaiDuLocal::getFaceOne(const QString &flag, const QList<float> &feature, QString &targetName, float &result)
//用当前图片的特征与特征数据库比对
result = 0;
int count = imgNames.count();
for (int i = 0; i < count; i++)
QString imgName = imgNames.at(i);
float currentResult = getFaceCompare(flag, feature, features.at(i));
//qDebug() << TIMEMS << "getFaceOne" << imgName << currentResult;
if (currentResult > result)
result = currentResult;
targetName = imgName;
qDebug() << TIMEMS << "getFaceOne result" << targetName << result;
void FaceBaiDuLocal::appendFace(const QString &flag, const QImage &img, const QString &txtFile)
QList<float> feature;
int msec;
QImage image = img;
bool ok = getFaceFeature(flag, image, feature, msec);
msleep(100);
qDebug() << TIMEMS << "getFaceFeature result" << ok << "appendFace" << txtFile;
if (ok)
emit receiveFaceFeature(flag, feature, msec);
//保存txt文件
QFile file(txtFile);
if (file.open(QFile::WriteOnly))
QStringList list;
foreach (float fea, feature)
list.append(QString::number(fea));
file.write(list.join(",").toLatin1());
file.close();
//保存图片文件
QString imgName = txtFile;
imgName = imgName.replace("txt", "jpg");
image.save(imgName, "jpg");
imgNames.append(QFileInfo(imgName).fileName());
features.append(feature);
void FaceBaiDuLocal::deleteFace(const QString &flag)
//从图片名称中找到标识符
int index = imgNames.indexOf(flag);
if (index >= 0)
imgNames.removeAt(index);
features.removeAt(index);
//删除图片文件
QString imgFileName = QString("%1/face/%2.jpg").arg(qApp->applicationDirPath()).arg(flag);
QFile imgFile(imgFileName);
imgFile.remove();
qDebug() << TIMEMS << "delete faceImage" << imgFileName;
//删除特征文件
QString txtFileName = QString("%1/face/%2.txt").arg(qApp->applicationDirPath()).arg(flag);
QFile txtFile(txtFileName);
txtFile.remove();
qDebug() << TIMEMS << "delete faceTxt" << txtFileName;