Fixed segmentation fault error in TRACK_vot::getNextFrame()

modules/datasets/samples/track_vot.cpp

@@ -82,8 +82,8 @@ int main(int argc, char *argv[])
 	for (int i = 0; i < dataset->getDatasetLength(datasetID); i++)
 	{
 		Mat frame;
-		dataset->getNextFrame(frame);
-
+		if (!dataset->getNextFrame(frame))
+			break;
 		//Draw Ground Truth BB
 		vector <Point2d> gtPoints =  dataset->getGT();
 		for (int j = 0; j < (int)(gtPoints.size()-1); j++)

modules/datasets/src/track_vot.cpp

@@ -211,7 +211,10 @@ namespace cv
 
 		bool  TRACK_votImpl::getNextFrame(Mat &frame)
 		{
-			frame = imread(data[activeDatasetID - 1][frameCounter]->imagePath);
+			if (frameCounter >= (int)data[activeDatasetID - 1].size())
+				return false;
+			string imgPath = data[activeDatasetID - 1][frameCounter]->imagePath;
+			frame = imread(imgPath);
 			frameCounter++;
 			return !frame.empty();
 		}