added cv::Filestorage based setup method for retina model

modules/contrib/include/opencv2/contrib/retina.hpp

@@ -174,6 +174,16 @@ public:
 	 */
 	void setup(std::string retinaParameterFile="", const bool applyDefaultSetupOnFailure=true);
 
+	
+	/**
+	 * try to open an XML retina parameters file to adjust current retina instance setup
+	 * => if the xml file does not exist, then default setup is applied
+	 * => warning, Exceptions are thrown if read XML file is not valid
+	 * @param fs : the open Filestorage which contains retina parameters
+         * @param applyDefaultSetupOnFailure : set to true if an error must be thrown on error
+	 */
+        void setup(cv::FileStorage &fs, const bool applyDefaultSetupOnFailure=true);
+
 	/**
 	 * try to open an XML retina parameters file to adjust current retina instance setup
 	 * => if the xml file does not exist, then default setup is applied

modules/contrib/src/retina.cpp

@@ -100,15 +100,34 @@ void Retina::setColorSaturation(const bool saturateColors, const float colorSatu
 
 struct Retina::RetinaParameters Retina::getParameters(){return _retinaParameters;}
 
+
 void Retina::setup(std::string retinaParameterFile, const bool applyDefaultSetupOnFailure)
 {
-	// open specified parameters file
-	std::cout<<"Retina::setup: setting up retina from parameter file : "<<retinaParameterFile<<std::endl;
+    try
+    {
+        // opening retinaParameterFile in read mode
+        cv::FileStorage fs(retinaParameterFile, cv::FileStorage::READ);
+        setup(fs, applyDefaultSetupOnFailure);
+    }catch(Exception &e)
+    {
+ 	std::cout<<"Retina::setup: wrong/unappropriate xml parameter file : error report :`n=>"<<e.what()<<std::endl;
+	if (applyDefaultSetupOnFailure)
+	{
+            std::cout<<"Retina::setup: resetting retina with default parameters"<<std::endl;
+	    setupOPLandIPLParvoChannel();
+	    setupIPLMagnoChannel();
+	}
+        else
+        {
+	    std::cout<<"=> keeping current parameters"<<std::endl;
+        }
+    }
+}
 
+void Retina::setup(cv::FileStorage &fs, const bool applyDefaultSetupOnFailure)
+{
 	try
 	{
-		// opening retinaParameterFile in read mode
-		cv::FileStorage fs(retinaParameterFile, cv::FileStorage::READ);
 		// read parameters file if it exists or apply default setup if asked for
 		if (!fs.isOpened())
 		{