diff --git a/src/bindings/csharp/openalpr-net/bitmapmat-net.h b/src/bindings/csharp/openalpr-net/bitmapmat-net.h
index a65acf3..cedbf94 100644
--- a/src/bindings/csharp/openalpr-net/bitmapmat-net.h
+++ b/src/bindings/csharp/openalpr-net/bitmapmat-net.h
@@ -65,7 +65,7 @@ namespace openalprnet {
 				channels = 4;
 				break;
 			default:
-				throw gcnew NotImplementedException();
+				throw gcnew NotSupportedException(bitmap->PixelFormat.ToString());
 			}
 
 			BitmapData^ bitmapData = bitmap->LockBits(
diff --git a/src/bindings/csharp/openalpr-net/helper-net.h b/src/bindings/csharp/openalpr-net/helper-net.h
index ce93a1b..806ace0 100644
--- a/src/bindings/csharp/openalpr-net/helper-net.h
+++ b/src/bindings/csharp/openalpr-net/helper-net.h
@@ -50,6 +50,11 @@ namespace openalprnet
 
 		static Bitmap^ MatToBitmap(cv::Mat mat)
 		{
+			if (mat.empty())
+			{
+				return nullptr;
+			}
+
 			const int width = mat.size().width;
 			const int height = mat.size().height;
 			const int channels = mat.channels();