使用dlib人脸识别的例子

来自官方的例子： http://dlib.net/face_detection_ex.cpp.html
做了一些修改：

#include <dlib/image_processing/frontal_face_detector.h>#include <dlib/gui_widgets.h>#include <dlib/image_io.h>#include <iostream>using namespace dlib;using namespace std;int main(int argc, char *argv[]){    try    {        //定义一个frontal_face_detctor类的实例detector，用get_frontal_face_detector函数初始化该实例        frontal_face_detector detector = get_frontal_face_detector();        image_window win;//一个显示窗口        array2d<unsigned char> img;        // 加载一张图片，从(图片路劲)加载到变量img        load_image(img, "D:\\img.jpg");        // Make the image bigger by a factor of two.  This is useful since        // the face detector looks for faces that are about 80 by 80 pixels        // or larger.  Therefore, if you want to find faces that are smaller        // than that then you need to upsample the image as we do here by        // calling pyramid_up().  So this will allow it to detect faces that        // are at least 40 by 40 pixels in size.  We could call pyramid_up()        // again to find even smaller faces, but note that every time we        // upsample the image we make the detector run slower since it must        // process a larger image.        /*确保检测图片是检测器的两倍。这第一点是十分有用的，因为脸部检测器搜寻的人脸大小是80*80或者更大。        因此，如果你想找到比80*80小的人脸，需要将检测图片进行上采样，我们可以调用pyramid_up()函数。        执行一次pyramid_up()我们能检测40*40大小的了，如果我们想检测更小的人脸，那还需要再次执行pyramid_up()函数。        注意，上采样后，速度会减慢！*/        pyramid_up(img);//对图像进行上采用，检测更小的人脸        // Now tell the face detector to give us a list of bounding boxes        // around all the faces it can find in the image.        //detector()函数检测人脸，返回一系列边界盒子        std::vector<rectangle> dets = detector(img);        cout << "Number of faces detected: " << dets.size() << endl;//dets.size 人脸数量        // Now we show the image on the screen and the face detections as        // red overlay boxes.        // 在原图片上显示结果        win.clear_overlay();        win.set_image(img);        win.add_overlay(dets, rgb_pixel(255, 0, 0));        cout << "Hit enter to process the next image..." << endl;        cin.get();    }    catch (exception& e)    {        cout << "\nexception thrown!" << endl;        cout << e.what() << endl;    }}

我使用QT+VS2015编译测试的，附上我的qmake

win32:CONFIG(release, debug|release): LIBS += $$PWD/dlib/dlib.libelse:win32:CONFIG(debug, debug|release): LIBS += $$PWD/dlib/dlibd.libDEFINES += DLIB_PNG_SUPPORTDEFINES += DLIB_JPEG_SUPPORTDEFINES += DLIB_HAVE_AVXINCLUDEPATH += D:/OpenCV/dlib-19.2/

环境路径参考上一篇dlib编译博文。

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有一点疑问：为什么显示出来的图片变成了黑白的？