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2018-09-19 01:58:57 -0500 answered a question What is the difference between pointer access of cv::Mat and CvMat?

err is a matrix which contains the distance of a pair of pixel after applying a transformation to them. Using the notati

2018-09-17 01:34:10 -0500 edited question What is the difference between pointer access of cv::Mat and CvMat?

What is the difference between pointer access of cv::Mat and CvMat? Hello! I have a question regarding a certain differ

2018-09-17 01:33:42 -0500 edited question What is the difference between pointer access of cv::Mat and CvMat?

What is the difference between pointer access of cv::Mat and CvMat? Hello! I have a question regarding a certain differ

2018-09-17 01:33:13 -0500 received badge  Editor (source)
2018-09-17 01:33:13 -0500 edited question What is the difference between pointer access of cv::Mat and CvMat?

What is the difference between pointer access of cv::Mat and CvMat? Hello! I have a question regarding a certain differ

2018-09-17 01:32:18 -0500 asked a question What is the difference between pointer access of cv::Mat and CvMat?

What is the difference between pointer access of cv::Mat and CvMat? Hello! I have a question regarding a certain differ

2018-04-17 02:50:00 -0500 asked a question How to interpret the rotation matrices of the homographybasedestimator?

How to interpret the rotation matrices of the homographybasedestimator? Good morning, I have question regarding OpenCV'

2018-04-12 01:54:06 -0500 asked a question Questions about the fundamental matrix and homographies

Questions about the fundamental matrix and homographies Hi there! Shortly I learned about the fundamental matrix and ha

2018-02-27 02:26:13 -0500 received badge  Enthusiast
2018-02-23 04:06:32 -0500 commented question Why use focal length as scale factor for warps?

Thanks again! I will give it a try. Two last question though: Was my assumption on why I have to scale the images corre

2018-02-23 01:19:18 -0500 commented question Why use focal length as scale factor for warps?

Thank you, LBerger! I think, I start to understand. If I capture a long wall, it is hard to keep the exact distance to t

2018-02-22 01:17:22 -0500 asked a question Why use focal length as scale factor for warps?

Why use focal length as scale factor for warps? Hi folks! I recently got my hands on the stitching_detailed.cpp and try

2017-08-04 01:19:03 -0500 commented question Algorithm behind findHomography() and the kind of homography returned by it

Hi Eduardo,

thank you for your answer. I already know the paper you mentioned and read it again and in addition the referenced literature. Unfortunately it didn't help me answering my questions. :-(

Best regards

Conundraah

2017-08-02 09:23:45 -0500 asked a question Algorithm behind findHomography() and the kind of homography returned by it

Hi folks!

I am dealing with the estimation and decomposition of homographies for a couple of days now and the very moment I think I got it I stumble upon new and even more mind-boggling questions. What I would like to understand is how a homography can be decomposed into parameters R and t how to estimate the camera path with the aforementioned parameters. I am well aware of the plethora of different algorithms to do that but I have a few questions that I could not answer after hours of googling and literature research.

As far as I know homographies are transformations which transform one set of points from one image plane to another and that they are the most general kind of transformation containing rotation, translation and non-linear scaling parameters. Today I read that there are two kinds of homographies: projective and euclidean homographies. From what I've read thus far, Euclidean homographies directly express the reconstruction of the relative motion between the views and the normal of the plane.

  • Is that correct?
  • Is it save to assume that a Euclidean homography can be thought of as a "real world" homography which describes my rotation and translation from one camera position to the next?
  • Are there any other important differences between projective and Euclidean homographies?
  • Which algorithm is used in findHomography() in OpenCV 2.4.13?
  • Does findHomography() in OpenCV 2.4.13 return a projective or euclidean homography?
  • When do I need a projective or a euclidean homography?

Your help is deeply appreciated!!!

Thank you

Conundraah

2016-09-23 01:37:41 -0500 received badge  Scholar (source)
2016-09-23 01:37:29 -0500 answered a question Error building Opencv 2.4.13 for Android with CMAKE

Sorry, I had a lot to do in the past week. I found the problem and managed to compile OpenCV 4 Andorid. It seems like there was a problem with the OpenCL module. After excluding it from the build process it worked without further problems.

Best regards

Conundraah

2016-09-12 02:34:48 -0500 asked a question Error building Opencv 2.4.13 for Android with CMAKE

Dear community,

last week I tried to build OpenCV 2.4.13 for Android on a Windows 10 x64 machine and encountered a rather puzzling error. As basis for the build process I used the following articles:

  1. https://github.com/opencv/opencv/wiki...
  2. http://www.codepool.biz/building-open...

I used the following tools:

  1. Android NDK r10d
  2. CMAKE 3.6.2
  3. OpenCV 2.4.13 from trunk

My build script looks like this:

"set PATH=%PATH%;D:\XYZ\1libBuild\cmake\bin;D:\XYZ\1libBuild\AndroidNdkR10d\prebuilt\windows-x86_64\bin

cmake -G "Unix Makefiles" -DCMAKE_TOOLCHAIN_FILE=D:\XYZ\1libBuild\opencv2.4.13\platforms\android\android.toolchain.cmake -DANDROID_NDK=D:\XYZ\1libBuild\AndroidNdkR10d -DCMAKE_BUILD_TYPE=Release D:\XYZ\1libBuild\opencv2.4.13

cmake --build "

The building process terminates after 80% with a very ambiguous error message:

arm-linux-androideabi-g++.exe: error: isystemD:\XYZ\1libBuild\AndroidNdkR10d\sources\cxx-stl\gnu-libstdc++\4.9\libs\armeabi-v7a\include: Invalid argument

make.exe[2]: +++ [modules\ocl\perf_precomp.hpp.gch\opencv_perf_ocl_release.gch] Error 1

make.exe[1]: +++ [modules\ocl\CMakeFiles\pch_Generate_opencv_perf_ocl.dir/all] Error 2

make.exe: +++ [all] Error 2

Please note, the "+" are "*" in the original error message. I exchanged them here, because the editor does not depict them properly.

Does anyone have similar issues during the build process or know where the error exactly comes from?

If no, could anyone please provide me with the libopencv_java.so build from OpenCV 2.4.13? It would greatly help me during my projects.

Thank you so much and have a great week!

Best regards

Conundraah