Access Violation at 0x00007FF6668A4219 reading 0x000002688D2ECC63

[singinwhale]

I get an access violation when I work with the Agisoft Sample Data (link). I have a fresh install of 9.2 on Windows 10 and left all settings as default. I just imported the images and went through the steps. It crashes halfway through the Triangulation step. Here is a Visual Studio 2015 dump if you need it. Stacktrace: -> Regard3D.exe!00007ff6668a4219()
Regard3D.exe!00007ff666896e85() Regard3D.exe!00007ff666aa8060() Regard3D.exe!00007ff666aa97e2() Regard3D.exe!00007ff666aa951f()

[pmoulon]

Thank you for yourfeedback.

I tested the scene with default settings on OpenMVG. (The lib used for the SfM backend)

Incremental SfM

Bundle Adjustment statistics (approximated RMSE):
 #views: 32
 #poses: 32
 #intrinsics: 1
 #tracks: 68642
 #residuals: 502312
 Initial RMSE: 0.216791
 Final RMSE: 0.195111
 Time (s): 4.62626

Global SfM

Bundle Adjustment statistics (approximated RMSE):
 #views: 32
 #poses: 32
 #intrinsics: 1
 #tracks: 36297
 #residuals: 348902
 Initial RMSE: 0.192323
 Final RMSE: 0.191442
 Time (s): 1.88458

So the error can comes from the provided correspondences that are computed differently in Regard3D.

[rhiestan]

Thanks @pmoulon for the investigation. I was able to reproduce the crash, however I still don't understand it. It doesn't happen in the triangulation itself, but in the ColorizeTracks function (which is done in Regard3D as part of the triangulation). The call stack is:

    Regard3D.exe!Eigen::DenseStorage<unsigned char,3,3,1,0>::DenseStorage<unsigned char,3,3,1,0>(const Eigen::DenseStorage<unsigned char,3,3,1,0> & other) Line 194 C++
    Regard3D.exe!Eigen::PlainObjectBase<Eigen::Matrix<unsigned char,3,1,0,3,1> >::PlainObjectBase<Eigen::Matrix<unsigned char,3,1,0,3,1> >(const Eigen::PlainObjectBase<Eigen::Matrix<unsigned char,3,1,0,3,1> > & other) Line 520  C++
    Regard3D.exe!Eigen::Matrix<unsigned char,3,1,0,3,1>::Matrix<unsigned char,3,1,0,3,1>(const Eigen::Matrix<unsigned char,3,1,0,3,1> & other) Line 371 C++
    [External Code] 
>   Regard3D.exe!OpenMVGHelper::ColorizeTracks(const openMVG::sfm::SfM_Data & sfm_data, std::vector<Eigen::Matrix<double,3,1,0,3,1>,std::allocator<Eigen::Matrix<double,3,1,0,3,1> > > & vec_3dPoints, std::vector<Eigen::Matrix<double,3,1,0,3,1>,std::allocator<Eigen::Matrix<double,3,1,0,3,1> > > & vec_tracksColor) Line 1904  C++
    Regard3D.exe!R3DTriangulationThread::Entry() Line 266   C++

The line in OpenMVGHelper::ColorizeTracks is:

vec_tracksColor[trackIds_to_contiguousIndexes[trackId]] = Vec3(color.r(), color.g(), color.b());

It looks like the constructor of Eigen::Vec3 crashes, but color looks fine:

-       color   {...}   openMVG::image::Rgb<unsigned char>
-       Eigen::Matrix<unsigned char,3,1,0,3,1>  {...}   Eigen::Matrix<unsigned char,3,1,0,3,1>
-       Eigen::PlainObjectBase<Eigen::Matrix<unsigned char,3,1,0,3,1> > {m_storage={m_data={array=0x000000000e48f170 "È\x3Ú... } } }    Eigen::PlainObjectBase<Eigen::Matrix<unsigned char,3,1,0,3,1> >
+       Eigen::MatrixBase<Eigen::Matrix<unsigned char,3,1,0,3,1> >  {...}   Eigen::MatrixBase<Eigen::Matrix<unsigned char,3,1,0,3,1> >
-       m_storage   {m_data={array=0x000000000e48f170 "È\x3Ú... } } Eigen::DenseStorage<unsigned char,3,3,1,0>
-       m_data  {array=0x000000000e48f170 "È\x3Ú... }   Eigen::internal::plain_array<unsigned char,3,0,0>
-       array   0x000000000e48f170 "È\x3Ú...    unsigned char[3]
        [0] 200 'È' unsigned char
        [1] 3 '\x3' unsigned char
        [2] 218 'Ú' unsigned char

I will continue to investigate.

[rhiestan]

I found the problem, it is not related to OpenMVG. Regard3D uses OpenCV to load the image, and it rotates the image if the EXIF data say so. That's why the keypoints have the rotated coordinates. In ColorizeTracks however the OpenMVG method is used to load the image, which does not rotate, and then the line const openMVG::image::RGBColor color = image(pt.y(), pt.x()); leads to the crash. I will set the flag IMREAD_IGNORE_ORIENTATION such that OpenCV will not rotate the image.