using copied version of solvePnPRansac for OpencV 3.3.1 too (along OpenCV2) to have stable transformation estimation (e.g., outdoor stereo demo is getting lost very often with the version of 3.3.1)

corelib/src/CMakeLists.txt

@@ -96,9 +96,12 @@ IF(OpenCV_VERSION_MAJOR EQUAL 2)
 SET(SRC_FILES
     ${SRC_FILES}
     opencv/Orb.cpp
-    opencv/solvepnp.cpp
 )
 ENDIF(OpenCV_VERSION_MAJOR EQUAL 2)
+SET(SRC_FILES
+    ${SRC_FILES}
+    opencv/solvepnp.cpp
+)
 
 # to get includes in visual studio
 IF(MSVC)

corelib/src/util3d_motion_estimation.cpp

@@ -37,9 +37,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <pcl/common/common.h>
 
-#if CV_MAJOR_VERSION < 3
 #include "opencv/solvepnp.h"
-#endif
 
 namespace rtabmap
 {
@@ -344,11 +342,10 @@ void solvePnPRansac(
 	{
 		minInliersCount = 4;
 	}
-#if CV_MAJOR_VERSION < 3
-	cv3::solvePnPRansac( //use OpenCV3 version of solvePnPRansac in OpenCV2
-#else
-	cv::solvePnPRansac( // use directly version from OpenCV 3
-#endif
+
+	// Use OpenCV3 version of solvePnPRansac in OpenCV2.
+	// FIXME: we should use this version of solvePnPRansac in newer 3.3.1 too, which seems a lot less stable!?!? Why!?
+	cv3::solvePnPRansac(
 			objectPoints,
 			imagePoints,
 			cameraMatrix,