diff --git a/CMakeLists.txt b/CMakeLists.txt
index 466094e..5d4916a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,10 +14,8 @@ set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -Wall -Wextra -pedantic -D_D
 # Eigen library
 include_directories( "/usr/include/eigen3/" )
 
-# OpenCV
-find_package( OpenCV 3.1 REQUIRED )
 
-# CUDA
+# CUDA (optional)
 find_package( CUDA )
 if (CUDA_FOUND)
     include( FindCUDA )
@@ -27,5 +25,18 @@ else()
     message(STATUS "CUDA not found; will skip bs_dsp")
 endif (CUDA_FOUND)
 
+# OpenCV
+find_package( OpenCV REQUIRED )
+if(OpenCV_VERSION VERSION_LESS "2.4.8")
+      message(FATAL_ERROR "ERROR: Can't find OpenCV 2.4.8+")
+endif()
+if(OpenCV_VERSION VERSION_LESS "3.0")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DHAS_OPENCV2")
+else()
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DHAS_OPENCV3")
+endif (OpenCV_VERSION VERSION_LESS "3.0")
+
 add_executable( lines lines.cpp )
 target_link_libraries( lines ${OpenCV_LIBS} )
+
+# vim: set et ts=4 sw=4:
diff --git a/lines.cpp b/lines.cpp
index baaecc1..717ea9f 100644
--- a/lines.cpp
+++ b/lines.cpp
@@ -1,6 +1,11 @@
 #include<cmath>
 #include<algorithm>
-#include<opencv2/opencv.hpp>
+
+#ifdef HAS_OPENCV3
+#include <opencv2/core.hpp> //Any OPENCV3 code
+#else
+#include <opencv2/core/core.hpp> //Any Opencv2 code
+#endif
 #include"lines.h"
 
 // all those colors are still visible on b/w (the first component is not so low)
@@ -185,7 +190,7 @@ int main(int argc, char *argv[])
 		color = (color==BLUE) ? MAGENTA : BLUE; //flip color at every group
 		cv::Point p1 = group[0];
 		cv::Point p2 = group[group.size()-1];
-		cv::arrowedLine(img, p1, p2, color, dotwidth>>2);
+		cv::line(img, p1, p2, color, dotwidth>>2);
 		std::cout << "simplified line: ";
 		for(cv::Point p: group)
 		{