Added prewarp reset by passing in empty prewarp config

src/openalpr/alpr_impl.cpp

@@ -661,7 +661,10 @@ namespace alpr
 
   void AlprImpl::setPrewarp(std::string prewarp_config)
   {
-    prewarp->initialize(prewarp_config);
+    if (prewarp_config.length() == 0)
+      prewarp ->clear();
+    else
+      prewarp->initialize(prewarp_config);
   }
 
 

src/openalpr/prewarp.cpp

@@ -103,6 +103,9 @@ namespace alpr
     if (config->debugTiming)
       cout << "Prewarp Initialization Time: " << diffclock(startTime, endTime) << "ms." << endl;
   }
+  void PreWarp::clear() {
+    this->valid = false;
+  }
 
   PreWarp::~PreWarp() {
   }

src/openalpr/prewarp.h

@@ -35,6 +35,7 @@ namespace alpr
     virtual ~PreWarp();
 
     void initialize(std::string prewarp_config);
+    void clear();
     
     cv::Mat warpImage(cv::Mat image);
     std::vector<cv::Point2f> projectPoints(std::vector<cv::Point2f> points, bool inverse);