erGrouping now uses a classifier for group validation instead of a set of heuristical ifos.

Updated documentation and sample to use the new function API

samples/cpp/textdetection.cpp

@@ -1,8 +1,12 @@
-
-//--------------------------------------------------------------------------------------------------
-//  A demo program of the Extremal Region Filter algorithm described in
-//  Neumann L., Matas J.: Real-Time Scene Text Localization and Recognition, CVPR 2012
-//--------------------------------------------------------------------------------------------------
+/*
+ * textdetection.cpp
+ *
+ * A demo program of the Extremal Region Filter algorithm described in
+ * Neumann L., Matas J.: Real-Time Scene Text Localization and Recognition, CVPR 2012
+ *
+ * Created on: Sep 23, 2013
+ *     Author: Lluis Gomez i Bigorda <lgomez AT cvc.uab.es>
+ */
 
 #include  "opencv2/opencv.hpp"
 #include  "opencv2/objdetect.hpp"
@@ -18,10 +22,13 @@ using  namespace cv;
 
 void show_help_and_exit(const char *cmd);
 void groups_draw(Mat &src, vector<Rect> &groups);
-void er_draw(Mat &src, Mat &dst, ERStat& er);
+void er_show(vector<Mat> &channels, vector<vector<ERStat> > &regions);
 
 int  main(int argc, const char * argv[])
 {
+    cout << endl << argv[0] << endl << endl;
+    cout << "Demo program of the Extremal Region Filter algorithm described in " << endl;
+    cout << "Neumann L., Matas J.: Real-Time Scene Text Localization and Recognition, CVPR 2012" << endl << endl;
 
     if (argc < 2) show_help_and_exit(argv[0]);
 
@@ -37,11 +44,13 @@ int  main(int argc, const char * argv[])
         channels.push_back(255-channels[c]);
 
     // Create ERFilter objects with the 1st and 2nd stage default classifiers
-    Ptr<ERFilter> er_filter1 = createERFilterNM1(loadClassifierNM1("trained_classifierNM1.xml"),8,0.00025,0.13,0.4,true,0.1);
-    Ptr<ERFilter> er_filter2 = createERFilterNM2(loadClassifierNM2("trained_classifierNM2.xml"),0.3);
+    Ptr<ERFilter> er_filter1 = createERFilterNM1(loadClassifierNM1("trained_classifierNM1.xml"),16,0.00015,0.13,0.2,true,0.1);
+    Ptr<ERFilter> er_filter2 = createERFilterNM2(loadClassifierNM2("trained_classifierNM2.xml"),0.5);
 
     vector<vector<ERStat> > regions(channels.size());
     // Apply the default cascade classifier to each independent channel (could be done in parallel)
+    cout << "Extracting Class Specific Extremal Regions from " << (int)channels.size() << " channels ..." << endl;
+    cout << "    (...) this may take a while (...)" << endl << endl;
     for (int c=0; c<(int)channels.size(); c++)
     {
         er_filter1->run(channels[c], regions[c]);
@@ -49,13 +58,18 @@ int  main(int argc, const char * argv[])
     }
 
     // Detect character groups
+    cout << "Grouping extracted ERs ... ";
     vector<Rect> groups;
-    erGrouping(channels, regions, groups);
+    erGrouping(channels, regions, "trained_classifier_erGrouping.xml", 0.5, groups);
 
     // draw groups
     groups_draw(src, groups);
     imshow("grouping",src);
-    waitKey(-1);
+
+    cout << "Done!" << endl << endl;
+    cout << "Press 'e' to show the extracted Extremal Regions, any other key to exit." << endl << endl;
+    if( waitKey (-1) == 101)
+        er_show(channels,regions);
 
     // memory clean-up
     er_filter1.release();
@@ -73,9 +87,6 @@ int  main(int argc, const char * argv[])
 
 void show_help_and_exit(const char *cmd)
 {
-    cout << endl << cmd << endl << endl;
-    cout << "Demo program of the Extremal Region Filter algorithm described in " << endl;
-    cout << "Neumann L., Matas J.: Real-Time Scene Text Localization and Recognition, CVPR 2012" << endl << endl;
     cout << "    Usage: " << cmd << " <input_image> " << endl;
     cout << "    Default classifier files (trained_classifierNM*.xml) must be in current directory" << endl << endl;
     exit(-1);
@@ -92,14 +103,25 @@ void groups_draw(Mat &src, vector<Rect> &groups)
     }
 }
 
-void er_draw(Mat &src, Mat &dst, ERStat& er)
+void er_show(vector<Mat> &channels, vector<vector<ERStat> > &regions)
 {
-
-    if (er.parent != NULL) // deprecate the root region
+    for (int c=0; c<(int)channels.size(); c++)
     {
-        int newMaskVal = 255;
-        int flags = 4 + (newMaskVal << 8) + FLOODFILL_FIXED_RANGE + FLOODFILL_MASK_ONLY;
-        floodFill(src,dst,Point(er.pixel%src.cols,er.pixel/src.cols),Scalar(255),0,Scalar(er.level),Scalar(0),flags);
+        Mat dst = Mat::zeros(channels[0].rows+2,channels[0].cols+2,CV_8UC1);
+        for (int r=0; r<(int)regions[c].size(); r++)
+        {
+            ERStat er = regions[c][r];
+            if (er.parent != NULL) // deprecate the root region
+            {
+                int newMaskVal = 255;
+                int flags = 4 + (newMaskVal << 8) + FLOODFILL_FIXED_RANGE + FLOODFILL_MASK_ONLY;
+                floodFill(channels[c],dst,Point(er.pixel%channels[c].cols,er.pixel/channels[c].cols),
+                          Scalar(255),0,Scalar(er.level),Scalar(0),flags);
+            }
+        }
+        char buff[10]; char *buff_ptr = buff;
+        sprintf(buff, "channel %d", c);
+        imshow(buff_ptr, dst);
     }
-
+    waitKey(-1);
 }