cv::flip only working around x-axis (MinGW) (Bug #2079)

Added by Erik Timmers over 12 years ago. Updated over 12 years ago.

Status:Cancelled Start date:2012-06-23
Priority:Normal Due date:
Assignee:Vadim Pisarevsky % Done:

0%
Category:core
Target version:-
Affected version: Operating System:
Difficulty: HW Platform:
Pull request:

Description

Flipping function void cv::flip(InputArray src, OutputArray dst, int flipCode) behaves strange.
When running

cv::Mat image, flipped;
image = cv::imread("image.jpg");
cv::flip(image, flipped, 0);
cv::imshow("View image", flipped);
things are working fine and image.jpg is shown upside down.
However, when flipCode is not equal to 0 (i.e. horizontal flip or both horizontal&vertical flipping), the executable is successfully build, but crashes immediately when executed. Apparently the horizontal flip is not working.

This all occurs using:
  • OpenCV 2.4.1 (OpenCV-2.4.1.exe)
  • Windows Vista (32 bit)
  • Qt Creator 1.2.1, incl. Qt libraries 4.8.1 for Windows (MinGW 4.4)

Other functions appear to work normal.
The weirdest thing is things work perfectly for vertical flipping, but somehow not for horizontal flipping (or when combining both).

History

#1
Updated by Stefan Hahn over 12 years ago

Same effect for
Windows 7 (x64)
QT Creator 2.0.1 based on QT 4.7.1 (Mingw32 4.4.0)

#2
Updated by Erik Timmers over 12 years ago

For completeness, the result of cv::getBuildInformation() for the Windows Vista build:

                                  
General configuration for OpenCV 2.4.1 =====================================

  Platform:
    Host:                        Windows 6.0 x86
    CMake:                       2.8.8
    CMake generator:             MinGW Makefiles
    CMake build tool:            C:/QtSDK/mingw/bin/mingw32-make.exe
    Configuration:               RELEASE

  C/C++:
    Built as dynamic libs?:      YES
    C++ Compiler:                C:/QtSDK/mingw/bin/g++.exe (ver 4.4.0)
    C++ flags (Release):         -mstackrealign -Wall -march=i686 -fomit-frame-pointer -msse -msse2 -mfpmath=sse -ffunction-sections -O2 -DNDEBUG   -DNDEBUG
    C++ flags (Debug):           -mstackrealign -Wall -march=i686 -fomit-frame-pointer -msse -msse2 -mfpmath=sse -ffunction-sections -g  -O0 -DDEBUG -D_DEBUG -ggdb3
    C Compiler:                  C:/QtSDK/mingw/bin/gcc.exe
    C flags (Release):           -mstackrealign -Wall -march=i686 -fomit-frame-pointer -msse -msse2 -mfpmath=sse -ffunction-sections -O2 -DNDEBUG  -DNDEBUG
    C flags (Debug):             -mstackrealign -Wall -march=i686 -fomit-frame-pointer -msse -msse2 -mfpmath=sse -ffunction-sections -g  -O0 -DDEBUG -D_DEBUG -ggdb3
    Linker flags (Release):      
    Linker flags (Debug):        

  OpenCV modules:
    To be built:                 calib3d contrib core features2d flann gpu highgui imgproc legacy ml nonfree objdetect photo stitching ts video videostab
    Disabled:                    -
    Disabled by dependency:      -
    Unavailable:                 androidcamera java python

  GUI: 
    QT 4.x:                      YES (ver 4.8.1 EDITION = OpenSource)
    QT OpenGL support:           NO
    OpenGL support:              NO

  Media I/O: 
    ZLib:                        build (ver 1.2.6)
    JPEG:                        build (ver 62)
    PNG:                         build (ver 1.5.9)
    TIFF:                        build (ver 42)
    JPEG 2000:                   build (ver 1.900.1)
    OpenEXR:                     NO

  Video I/O:
    FFMPEG:                      YES (prebuilt binaries)
      codec:                     YES (ver 53.61.100)
      format:                    YES (ver 53.32.100)
      util:                      YES (ver 51.35.100)
      swscale:                   YES (ver 2.1.100)
      gentoo-style:              YES
    OpenNI:                      NO
    OpenNI PrimeSensor Modules:  NO
    PvAPI:                       NO
    DirectShow:                  YES
    XIMEA:                       NO

  Other third-party libraries:
    Use IPP:                     NO
    Use TBB:                     NO
    Use Cuda:                    NO
    Use Eigen:                   NO

  Python:
    Interpreter:                 NO

  Documentation:
    Build Documentation:         NO
    Sphinx:                      NO
    PdfLaTeX compiler:           NO

  Tests and samples:
    Tests:                       YES
    Performance tests:           YES
    Examples:                    NO

  Install path:                  C:/opencv/install

  cvconfig.h is in:              C:/opencv
-----------------------------------------------------------------

#3
Updated by Stefan Hahn over 12 years ago

Addition:
No error when opencv is compiled with debug option.
This seems to be -o3 optimization going astray.
Looking at the generated compiler code for the innermost and last loop in flipHoriz it becomes clear, that this has been optimized into nonsense. There even is no loop on "limit" any more.

Recommendation:
To keep Qt users happy I would propose to return to the flipHoriz implementation from previous releases.

#4
Updated by Andrey Kamaev over 12 years ago

Stefan, flipHoriz was not touched for 11 month. Which means it is the same as was in OpenCV 2.3 release.

#5
Updated by Vadim Pisarevsky over 12 years ago

we actually found MinGW being very buggy and do not recommend to go beyond -O1 with it, which is surprising since GCC on Linux is rock solid. We could try to rewrite this and that function and after multiple attempts find which version is compatible with MinGW broken logic. But it's not best way to spend time. Instead, you could either use -O1, or use newer version of MinGW (MinGW 4.6.x seems to be more stable) or use Visual Studio Express 2010, which is free (as in "beer").

#6
Updated by Vadim Pisarevsky over 12 years ago

the report was cancelled, since this is a known bug in the old version of MinGW

  • Status changed from Open to Cancelled

#7
Updated by Aziz Baibabaev over 12 years ago

Vadim Pisarevsky wrote:

we actually found MinGW being very buggy and do not recommend to go beyond -O1 with it, which is surprising since GCC on Linux is rock solid. We could try to rewrite this and that function and after multiple attempts find which version is compatible with MinGW broken logic. But it's not best way to spend time. Instead, you could either use -O1, or use newer version of MinGW (MinGW 4.6.x seems to be more stable) or use Visual Studio Express 2010, which is free (as in "beer").

-O1 does not seem to cut it with GCC 4.4.0, have to turn off optimization completely.

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