2 * Copyright (c) 2011. Philipp Wagner <bytefish[at]gmx[dot]de>.
3 * Released to public domain under terms of the BSD Simplified license.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 * * Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * * Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * * Neither the name of the organization nor the names of its contributors
13 * may be used to endorse or promote products derived from this software
14 * without specific prior written permission.
16 * See <http://www.opensource.org/licenses/bsd-license>
19 #include "opencv2/core.hpp"
20 #include "opencv2/core/utility.hpp"
21 #include "opencv2/highgui.hpp"
22 #include "opencv2/contrib.hpp"
31 static Mat toGrayscale(InputArray _src) {
32 Mat src = _src.getMat();
33 // only allow one channel
34 if(src.channels() != 1) {
35 CV_Error(Error::StsBadArg, "Only Matrices with one channel are supported");
37 // create and return normalized image
39 cv::normalize(_src, dst, 0, 255, NORM_MINMAX, CV_8UC1);
43 static void read_csv(const string& filename, vector<Mat>& images, vector<int>& labels, char separator = ';') {
44 std::ifstream file(filename.c_str(), ifstream::in);
46 string error_message = "No valid input file was given, please check the given filename.";
47 CV_Error(Error::StsBadArg, error_message);
49 string line, path, classlabel;
50 while (getline(file, line)) {
51 stringstream liness(line);
52 getline(liness, path, separator);
53 getline(liness, classlabel);
54 if(!path.empty() && !classlabel.empty()) {
55 images.push_back(imread(path, 0));
56 labels.push_back(atoi(classlabel.c_str()));
61 int main(int argc, const char *argv[]) {
62 // Check for valid command line arguments, print usage
63 // if no arguments were given.
65 cout << "usage: " << argv[0] << " <csv.ext>" << endl;
68 // Get the path to your CSV.
69 string fn_csv = string(argv[1]);
70 // These vectors hold the images and corresponding labels.
73 // Read in the data. This can fail if no valid
74 // input filename is given.
76 read_csv(fn_csv, images, labels);
77 } catch (cv::Exception& e) {
78 cerr << "Error opening file \"" << fn_csv << "\". Reason: " << e.msg << endl;
79 // nothing more we can do
82 // Quit if there are not enough images for this demo.
83 if(images.size() <= 1) {
84 string error_message = "This demo needs at least 2 images to work. Please add more images to your data set!";
85 CV_Error(Error::StsError, error_message);
87 // Get the height from the first image. We'll need this
88 // later in code to reshape the images to their original
90 int height = images[0].rows;
91 // The following lines simply get the last images from
92 // your dataset and remove it from the vector. This is
93 // done, so that the training data (which we learn the
94 // cv::FaceRecognizer on) and the test data we test
95 // the model with, do not overlap.
96 Mat testSample = images[images.size() - 1];
97 int testLabel = labels[labels.size() - 1];
100 // The following lines create an Eigenfaces model for
101 // face recognition and train it with the images and
102 // labels read from the given CSV file.
103 // This here is a full PCA, if you just want to keep
104 // 10 principal components (read Eigenfaces), then call
105 // the factory method like this:
107 // cv::createEigenFaceRecognizer(10);
109 // If you want to create a FaceRecognizer with a
110 // confidennce threshold, call it with:
112 // cv::createEigenFaceRecognizer(10, 123.0);
114 Ptr<FaceRecognizer> model = createEigenFaceRecognizer();
115 model->train(images, labels);
116 // The following line predicts the label of a given
118 int predictedLabel = model->predict(testSample);
120 // To get the confidence of a prediction call the model with:
122 // int predictedLabel = -1;
123 // double confidence = 0.0;
124 // model->predict(testSample, predictedLabel, confidence);
126 string result_message = format("Predicted class = %d / Actual class = %d.", predictedLabel, testLabel);
127 cout << result_message << endl;
128 // Sometimes you'll need to get/set internal model data,
129 // which isn't exposed by the public cv::FaceRecognizer.
130 // Since each cv::FaceRecognizer is derived from a
131 // cv::Algorithm, you can query the data.
133 // First we'll use it to set the threshold of the FaceRecognizer
134 // to 0.0 without retraining the model. This can be useful if
135 // you are evaluating the model:
137 model->set("threshold", 0.0);
138 // Now the threshold of this model is set to 0.0. A prediction
139 // now returns -1, as it's impossible to have a distance below
141 predictedLabel = model->predict(testSample);
142 cout << "Predicted class = " << predictedLabel << endl;
143 // Here is how to get the eigenvalues of this Eigenfaces model:
144 Mat eigenvalues = model->getMat("eigenvalues");
145 // And we can do the same to display the Eigenvectors (read Eigenfaces):
146 Mat W = model->getMat("eigenvectors");
147 // From this we will display the (at most) first 10 Eigenfaces:
148 for (int i = 0; i < min(10, W.cols); i++) {
149 string msg = format("Eigenvalue #%d = %.5f", i, eigenvalues.at<double>(i));
151 // get eigenvector #i
152 Mat ev = W.col(i).clone();
153 // Reshape to original size & normalize to [0...255] for imshow.
154 Mat grayscale = toGrayscale(ev.reshape(1, height));
155 // Show the image & apply a Jet colormap for better sensing.
157 applyColorMap(grayscale, cgrayscale, COLORMAP_JET);
158 imshow(format("%d", i), cgrayscale);