daviddoria/examples

Many examples of many features of many software packages

examples's Issues

What is the math function in this example?

Hi, I want to use LM algorithm in my application.
Could you show me the function in
LMTest.cpp ?

how to use ICP on 2D data?

I want to apply icp on two TSNE data which are 2D, could you tell me how to use this algorithm please

thank you

Error: Assertion failed (_dst.fixedType()) in cv::convertPointsHomogeneous,

Hi Sir,
I run your'e example provided in Git, it thrown error.

What it mean:

OpenCV(4.5.5) Error: Assertion failed (_dst.fixedType()) in cv::convertPointsHomogeneous, file C:\build\master_winpack-build-win64-vc15\opencv\modules\calib3d\src\fundam.cpp, line 1202

https://github.com/daviddoria/Examples/blob/master/c%2B%2B/OpenCV/ProjectPoints/ProjectPoints.cxx

Convert Error

Hi David,

When I run stereo_calibrate.cxx I have an error like below.
What is the problem?
What shoul I do?
Thank you.

../stereo_calibrate/main.cpp:94: error: cannot convert 'CvTermCriteria' to 'int' for argument '13' to 'double cv::stereoCalibrate(cv::InputArrayOfArrays, cv::InputArrayOfArrays, cv::InputArrayOfArrays, cv::InputOutputArray, cv::InputOutputArray, cv::InputOutputArray, cv::InputOutputArray, cv::Size, cv::OutputArray, cv::OutputArray, cv::OutputArray, cv::OutputArray, int, cv::TermCriteria)'
CV_CALIB_SAME_FOCAL_LENGTH | CV_CALIB_ZERO_TANGENT_DIST);
^

Error while make - /Examples-master/c++/PCL/Descriptors/ViewpointFeatureHistogram/CMakeLists.txt

When I try to run VFH, after installing PCL I get this error while make

[ 50%] Linking CXX executable ViewpointFeatureHistogram
/usr/bin/ld: CMakeFiles/ViewpointFeatureHistogram.dir/ViewpointFeatureHistogram.cpp.o: undefined reference to symbol '_ZN5boost6system15system_categoryEv'
//usr/lib/x86_64-linux-gnu/libboost_system.so.1.58.0: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
CMakeFiles/ViewpointFeatureHistogram.dir/build.make:94: recipe for target 'ViewpointFeatureHistogram' failed
make[2]: *** [ViewpointFeatureHistogram] Error 1
CMakeFiles/Makefile2:67: recipe for target 'CMakeFiles/ViewpointFeatureHistogram.dir/all' failed
make[1]: *** [CMakeFiles/ViewpointFeatureHistogram.dir/all] Error 2
Makefile:83: recipe for target 'all' failed
make: *** [all] Error 2

error:UmfPack not a member of Eigen

error: ‘UmfPack’ is not a member of ‘Eigen’
Eigen::SparseLU<Eigen::SparseMatrix, Eigen::UmfPack> lu_of_A(AtA);

Result values are wrong

I run this code. I expect that positions of projectedPoints[i] is equal to position of imagepoints[i]. But when I write their values, they are different.

Is there a problem on this code?

compilation wrong

I used your cmake file: https://github.com/daviddoria/Examples/blob/master/c%2B%2B/PCL/Descriptors/PrincipalCurvaturesEstimation/CMakeLists.txt

and https://github.com/daviddoria/Examples/blob/master/c%2B%2B/PCL/Descriptors/PrincipalCurvaturesEstimation/PrincipalCurvaturesEstimation.cpp

It seems that I got error

Linking CXX executable PrincipalCurvaturesEstimation
/usr/bin/ld: CMakeFiles/PrincipalCurvaturesEstimation.dir/PrincipalCurvaturesEstimation.cpp.o: undefined reference to symbol '_ZN5boost6system15system_categoryEv'
//usr/lib/x86_64-linux-gnu/libboost_system.so.1.54.0: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
make[2]: *** [PrincipalCurvaturesEstimation] Error 1
make[1]: *** [CMakeFiles/PrincipalCurvaturesEstimation.dir/all] Error 2
make: *** [all] Error 2

Do you know what is going on?

About measuring calibration quality with epipolar line

Hello David, thank you for your examples. For example of stereo rectification ("Examples / c++ / OpenCV / StereoRectification / orig.cxx"), when measuring the calibration quality by computing the distance between the corresponding point and epipolar line (from line 204 to 211), I was wondering which point set should be used, the distorted or the undistorted. Since the epipolar line and the fundamental matrix are for the undistorted coordinate system, my point of view is it should be the undistorted point set rather than the distorted set used in your code.

Is the derivative correct in AnalyticDerivative.cpp?

In the example /Eigen/LevenbergMarquardt/AnalyticDerivative.cpp, line 14, the function f_0 is
fvec(0) = x(0) - 5.0;
that isr f_0 = x - 5

I understand this as we are minimizing y = (x - 5.0)^2.

The derivative in line 21 is
fjac(0) = 2.0f * x(0);

However, my understanding is fjac(0) should be derivative of f_0, which results in
fjac(0) = 1.0f;

I am trying to use Eigen::LevenbergMarquardt without success yet. Can you please explain what is wrong in my understanding?