C++ sample code to detect facial features

samples/cpp/facial_features.cpp

+/*
+ * Author: Samyak Datta (datta[dot]samyak[at]gmail.com)
+ *
+ * A program to detect facial feature points using
+ * Haarcascade classifiers for face, eyes, nose and mouth
+ *
+ */
+
+#include "opencv2/objdetect/objdetect.hpp"
+#include "opencv2/highgui/highgui.hpp"
+#include "opencv2/imgproc/imgproc.hpp"
+
+#include <iostream>
+#include <cstdio>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+using namespace cv;
+
+// Functions to parse command-line arguments
+static string getCommandOption(const vector<string>&, const string&);
+static void setCommandOptions(vector<string>&, int, char**);
+static bool doesCmdOptionExist(const vector<string>& , const string&);
+
+// Functions for facial feature detection
+static void help();
+static void detectFaces(Mat&, vector<Rect_<int> >&, string);
+static void detectEyes(Mat&, vector<Rect_<int> >&, string);
+static void detectNose(Mat&, vector<Rect_<int> >&, string);
+static void detectMouth(Mat&, vector<Rect_<int> >&, string);
+static void detectFacialFeaures(Mat&, const vector<Rect_<int> >, string, string, string);
+
+string input_image_path;
+string face_cascade_path, eye_cascade_path, nose_cascade_path, mouth_cascade_path;
+
+int main(int argc, char** argv)
+{
+    if(argc < 3)
+    {
+        help();
+        return 1;
+    }
+
+    // Extract command-line options
+    vector<string> args;
+    setCommandOptions(args, argc, argv);
+
+    input_image_path = argv[1];
+    face_cascade_path = argv[2];
+    eye_cascade_path = (doesCmdOptionExist(args, "-eyes")) ? getCommandOption(args, "-eyes") : "";
+    nose_cascade_path = (doesCmdOptionExist(args, "-nose")) ? getCommandOption(args, "-nose") : "";
+    mouth_cascade_path = (doesCmdOptionExist(args, "-mouth")) ? getCommandOption(args, "-mouth") : "";
+
+    // Load image and cascade classifier files
+    Mat image;
+    image = imread(input_image_path);
+
+    // Detect faces and facial features
+    vector<Rect_<int> > faces;
+    detectFaces(image, faces, face_cascade_path);
+    detectFacialFeaures(image, faces, eye_cascade_path, nose_cascade_path, mouth_cascade_path);
+
+    imshow("Result", image);
+
+    waitKey(0);
+    return 0;
+}
+
+void setCommandOptions(vector<string>& args, int argc, char** argv)
+{
+    for(int i = 1; i < argc; ++i)
+    {
+        args.push_back(argv[i]);
+    }
+    return;
+}
+
+string getCommandOption(const vector<string>& args, const string& opt)
+{
+    string answer;
+    vector<string>::const_iterator it = find(args.begin(), args.end(), opt);
+    if(it != args.end() && (++it != args.end()))
+        answer = *it;
+    return answer;
+}
+
+bool doesCmdOptionExist(const vector<string>& args, const string& opt)
+{
+    vector<string>::const_iterator it = find(args.begin(), args.end(), opt);
+    return (it != args.end());
+}
+
+static void help()
+{
+    cout << "\nThis file demonstrates facial feature points detection using Haarcascade classifiers.\n"
+        "The program detects a face and eyes, nose and mouth inside the face."
+        "The code has been tested on the Japanese Female Facial Expression (JAFFE) database and found"
+        "to give reasonably accurate results. \n";
+
+    cout << "\nUSAGE: ./cpp-example-facial_features [IMAGE] [FACE_CASCADE] [OPTIONS]\n"
+        "IMAGE\n\tPath to the image of a face taken as input.\n"
+        "FACE_CASCSDE\n\t Path to a haarcascade classifier for face detection.\n"
+        "OPTIONS: \nThere are 3 options available which are described in detail. There must be a "
+        "space between the option and it's argument (All three options accept arguments).\n"
+        "\t-eyes : Specify the haarcascade classifier for eye detection.\n"
+        "\t-nose : Specify the haarcascade classifier for nose detection.\n"
+        "\t-mouth : Specify the haarcascade classifier for mouth detection.\n";
+
+
+    cout << "EXAMPLE:\n"
+        "(1) ./cpp-example-facial_features image.jpg face.xml -eyes eyes.xml -mouth mouth.xml\n"
+        "\tThis will detect the face, eyes and mouth in image.jpg.\n"
+        "(2) ./cpp-example-facial_features image.jpg face.xml -nose nose.xml\n"
+        "\tThis will detect the face and nose in image.jpg.\n"
+        "(3) ./cpp-example-facial_features image.jpg face.xml\n"
+        "\tThis will detect only the face in image.jpg.\n";
+
+    cout << " \n\nThe classifiers for face and eyes can be downloaded from : "
+        " \nhttps://github.com/Itseez/opencv/tree/master/data/haarcascades";
+
+    cout << "\n\nThe classifiers for nose and mouth can be downloaded from : "
+        " \nhttps://github.com/Itseez/opencv_contrib/tree/master/modules/face/data/cascades\n";
+}
+
+static void detectFaces(Mat& img, vector<Rect_<int> >& faces, string cascade_path)
+{
+    CascadeClassifier face_cascade;
+    face_cascade.load(cascade_path);
+
+    face_cascade.detectMultiScale(img, faces, 1.15, 3, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
+    return;
+}
+
+static void detectFacialFeaures(Mat& img, const vector<Rect_<int> > faces, string eye_cascade,
+        string nose_cascade, string mouth_cascade)
+{
+    for(unsigned int i = 0; i < faces.size(); ++i)
+    {
+        // Mark the bounding box enclosing the face
+        Rect face = faces[i];
+        rectangle(img, Point(face.x, face.y), Point(face.x+face.width, face.y+face.height),
+                Scalar(255, 0, 0), 1, 4);
+
+        // Eyes, nose and mouth will be detected inside the face (region of interest)
+        Mat ROI = img(Rect(face.x, face.y, face.width, face.height));
+
+        // Check if all features (eyes, nose and mouth) are being detected
+        bool is_full_detection = false;
+        if( (!eye_cascade.empty()) && (!nose_cascade.empty()) && (!mouth_cascade.empty()) )
+            is_full_detection = true;
+
+        // Detect eyes if classifier provided by the user
+        if(!eye_cascade.empty())
+        {
+            vector<Rect_<int> > eyes;
+            detectEyes(ROI, eyes, eye_cascade);
+
+            // Mark points corresponding to the centre of the eyes
+            for(unsigned int j = 0; j < eyes.size(); ++j)
+            {
+                Rect e = eyes[j];
+                circle(ROI, Point(e.x+e.width/2, e.y+e.height/2), 3, Scalar(0, 255, 0), -1, 8);
+                /* rectangle(ROI, Point(e.x, e.y), Point(e.x+e.width, e.y+e.height),
+                    Scalar(0, 255, 0), 1, 4); */
+            }
+        }
+
+        // Detect nose if classifier provided by the user
+        double nose_center_height = 0.0;
+        if(!nose_cascade.empty())
+        {
+            vector<Rect_<int> > nose;
+            detectNose(ROI, nose, nose_cascade);
+
+            // Mark points corresponding to the centre (tip) of the nose
+            for(unsigned int j = 0; j < nose.size(); ++j)
+            {
+                Rect n = nose[j];
+                circle(ROI, Point(n.x+n.width/2, n.y+n.height/2), 3, Scalar(0, 255, 0), -1, 8);
+                nose_center_height = (n.y + n.height/2);
+            }
+        }
+
+        // Detect mouth if classifier provided by the user
+        double mouth_center_height = 0.0;
+        if(!mouth_cascade.empty())
+        {
+            vector<Rect_<int> > mouth;
+            detectMouth(ROI, mouth, mouth_cascade);
+
+            for(unsigned int j = 0; j < mouth.size(); ++j)
+            {
+                Rect m = mouth[j];
+                mouth_center_height = (m.y + m.height/2);
+
+                // The mouth should lie below the nose
+                if( (is_full_detection) && (mouth_center_height > nose_center_height) )
+                {
+                    rectangle(ROI, Point(m.x, m.y), Point(m.x+m.width, m.y+m.height), Scalar(0, 255, 0), 1, 4);
+                }
+                else if( (is_full_detection) && (mouth_center_height <= nose_center_height) )
+                    continue;
+                else
+                    rectangle(ROI, Point(m.x, m.y), Point(m.x+m.width, m.y+m.height), Scalar(0, 255, 0), 1, 4);
+            }
+        }
+
+    }
+
+    return;
+}
+
+static void detectEyes(Mat& img, vector<Rect_<int> >& eyes, string cascade_path)
+{
+    CascadeClassifier eyes_cascade;
+    eyes_cascade.load(cascade_path);
+
+    eyes_cascade.detectMultiScale(img, eyes, 1.20, 5, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
+    return;
+}
+
+static void detectNose(Mat& img, vector<Rect_<int> >& nose, string cascade_path)
+{
+    CascadeClassifier nose_cascade;
+    nose_cascade.load(cascade_path);
+
+    nose_cascade.detectMultiScale(img, nose, 1.20, 5, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
+    return;
+}
+
+static void detectMouth(Mat& img, vector<Rect_<int> >& mouth, string cascade_path)
+{
+    CascadeClassifier mouth_cascade;
+    mouth_cascade.load(cascade_path);
+
+    mouth_cascade.detectMultiScale(img, mouth, 1.20, 5, 0|CASCADE_SCALE_IMAGE, Size(30, 30));
+    return;
+}