diff --git a/felz/src/segment-image.h b/felz/src/segment-image.h
index 5d03233..d541f77 100644
--- a/felz/src/segment-image.h
+++ b/felz/src/segment-image.h
@@ -18,7 +18,7 @@ cv::Vec3b random_rgb(){
 }
 
 /// Difference between two pixels p1, p2 in image
-static inline float diff(cv::Mat image, int p1, int p2) {
+static inline float diff(const cv::Mat & image, int p1, int p2) {
 	if (image.channels() == 3) {
 		cv::Vec3f a = image.at<cv::Vec3f>(p1);
 		cv::Vec3f b = image.at<cv::Vec3f>(p2);
diff --git a/objectness/Objectness/CMakeLists.txt b/objectness/Objectness/CMakeLists.txt
index 4c20f95..a8e67af 100644
--- a/objectness/Objectness/CMakeLists.txt
+++ b/objectness/Objectness/CMakeLists.txt
@@ -17,7 +17,7 @@ if (${CMAKE_COMPILER_IS_GNUCXX})
   set(OPENMP_FLAG "-fopenmp -std=c++11 -ftree-vectorize")
 endif (${CMAKE_COMPILER_IS_GNUCXX})
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OPENMP_FLAG} -g")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OPENMP_FLAG} -O3")
 
 #add_executable(${PROJECT_NAME} Main.cpp CmFile.cpp CmShow.cpp DataSetVOC.cpp FilterTIG.cpp Objectness.cpp stdafx.cpp)
 #target_link_libraries(${PROJECT_NAME} ${OpenCV_LIBRARIES} LIBLINEAR BLAS)