Fixed facerec_eigenfaces.cpp demo sample: it contained hardcoded values, which…

Fixed facerec_eigenfaces.cpp demo sample: it contained hardcoded values, which made wrong element access possible. Fixed unsigned integer/signed integer warnings in facerec.cpp.

modules/contrib/doc/facerec/src/facerec_eigenfaces.cpp

@@ -169,8 +169,9 @@ int main(int argc, const char *argv[]) {
             imwrite(format("%s/eigenface_%d.png", output_folder.c_str(), i), norm_0_255(cgrayscale));
         }
     }
+
     // Display or save the image reconstruction at some predefined steps:
-    for(int num_components = 10; num_components < 300; num_components+=15) {
+    for(int num_components = min(W.cols, 10); num_components < min(W.cols, 300); num_components+=15) {
         // slice the eigenvectors from the model
         Mat evs = Mat(W, Range::all(), Range(0, num_components));
         Mat projection = subspaceProject(evs, mean, images[0].reshape(1,1));

modules/contrib/src/facerec.cpp

@@ -751,11 +751,11 @@ void LBPH::train(InputArray _src, InputArray _lbls) {
         CV_Error(CV_StsBadArg, error_message);
     }
     // append labels to _labels matrix
-    for(int labelIdx = 0; labelIdx < labels.total(); labelIdx++) {
-        _labels.push_back(labels.at<int>(labelIdx));
+    for(size_t labelIdx = 0; labelIdx < labels.total(); labelIdx++) {
+        _labels.push_back(labels.at<int>((int)labelIdx));
     }
     // store the spatial histograms of the original data
-    for(int sampleIdx = 0; sampleIdx < src.size(); sampleIdx++) {
+    for(size_t sampleIdx = 0; sampleIdx < src.size(); sampleIdx++) {
         // calculate lbp image
         Mat lbp_image = elbp(src[sampleIdx], _radius, _neighbors);
         // get spatial histogram from this lbp image
@@ -788,11 +788,11 @@ void LBPH::predict(InputArray _src, int &minClass, double &minDist) const {
     // find 1-nearest neighbor
     minDist = DBL_MAX;
     minClass = -1;
-    for(int sampleIdx = 0; sampleIdx < _histograms.size(); sampleIdx++) {
+    for(size_t sampleIdx = 0; sampleIdx < _histograms.size(); sampleIdx++) {
         double dist = compareHist(_histograms[sampleIdx], query, CV_COMP_CHISQR);
         if((dist < minDist) && (dist < _threshold)) {
             minDist = dist;
-            minClass = _labels.at<int>(sampleIdx);
+            minClass = _labels.at<int>((int) sampleIdx);
         }
     }
 }