I am new to opencv and I am using opencv for windows. How can I see the source code for a specific function of an opencv library ? I just one want to get an idea of how that specific machine vision algorithm is implemented.
You can get the OpenCV source code from https://github.com/opencv. An easy way to find the header for a function is to open an explorer window in OPENCV_HOME\build\include (where is the location where you chose to install OpenCV) and use the search box to find the header file that contains your function - this will help you know what module it is in. Then you can search in OPENCV_HOME\modules\MODULE_NAME\src to find the source of the the function. This is even easier if you install a search tool like grepWin.
Looking at the source is almost essential for finding out why those pesky OpenCV exceptions are thrown. It also means that you can answer most things about OpenCV yourself without having to ask here.
Here is a direct link to an excellent source code search, courtesy of Github. This is a very straightforward way to find the implementation and internal usages of a function or type.
All the source is now on github:
https://github.com/opencv/opencv and you can use it's search functionalities as well.
I found the answer by Drew Noakes to be the most helpful, especially given the fact that repository structures keep changing over time.
To search in the code or in other places inside a repository using a keyword, the instructions here can be followed.
What would be even easier for first-timers however, would be to simply search for a key word in the github search bar. Then the appropriate advanced search option would generate the tags described in the the earlier linked tutorial.
Related
I am a newbie with Autotools and currently trying to create a configure.ac file in order to check for several dependencies for the later installation of my program.
Now, I want to check the existence of certain libraries and I have found that using AC_CHECK_LIB can do the trick. I think PCK_CHECK_MODULES could help too but I would like to stick to the former unless PCK_CHECK_MODULES solved my problem:
AC_CHECK_LIB does what is expected to do which is to look for the library and perform an action if found or another one if not found, but, my question then is:
If AC_CHECK_LIB finds my library, how can I obtain the exact path of this library? That is to say, if the AC_CHECK_LIB I have is:
AC_CHECK_LIB (foo, function, [action-if-found], [action-if-not-found])
Is there any way for me to get the exact path of this foo library if it is found?
Thanks,
If AC_CHECK_LIB finds my library, how can I obtain the exact path of this library?
AC_CHECK_LIB does not provide any mechanism by which you could do so. It does not determine an actual location itself. Per its documentation, this is what it actually does:
Test whether the library library is available by trying to link a test
program that calls function function with the library. function should
be a function provided by the library.
When AC_CHECK_LIB succeeds, then, it knows only that the linker found a library corresponding to the given library name that provides a function having the specified function name. It doesn't know where the linker found it. On the flip side, when that macros does not find a library, that does not necessarily mean it is unavailable, but rather that the linker does not find it subject to the link options, if any, in effect at that point.
Note, too, that that's perfectly satisfactory for many purposes. You need to know the actual location only if you want to use that to locate some other, related resource. And it's rare that configure can find a library without help, yet needs extra information to locate related resources.
I have trouble to find the RANSAC (findHomography() in calib3d.hpp) sourcecode file (.cpp) in the opencv folder. Does anyone know where the source code is?
Is there in common and easy way to determine where the source code of a specific function in the OpenCV folder is? or do i need to look trough every file?
Here is the source code for the function findHomography() - https://github.com/opencv/opencv/blob/master/modules/calib3d/src/fundam.cpp#L319
Q:
Is there in common and easy way to determine where the source code of
a specific function in the OpenCV folder is? or do i need to look
trough every file?
A:
Google is an extremely powerful tool, I tend to just Google the function I am looking for followed by "opencv github", if I can't find it by doing that I crawl through the source code.
A bit of a general question, but what is the most popular/common/easiest way of creating a custom pcore?
I have seen some examples and they were mostly done on Matlab and since I do not have Matlab anywhere, I am a bit lost here. There has got to be a proper way of doing without it!
Thank you in advance!!!
You can create it with VHDL or Verilog languages, but after that you need to make few files like .mdp and .pao, create directory move all the files there and then put the directory to a library.
Detailed information you can find in Xilinx Manual
I like the help which is provided by --help-module. Here you can read how to add new libraries and which variables are being set. Because I only occasionally create a framework from scratch I only add libraries once and forget how to add them for the next time.
So, if I want to create a new project I only have to make a quick search with --help-module and the package I want to use. Unfortunately OpenCV is not in this list. So, I am curious if there is a way to add a help for Opencv?
TLTR; I want to add a help for OpenCV. Where I can refresh my mind on how to find opencv and how link against it etc.
I doubt this can be done.
The help module is generated from the RST CMake documentation. You are not supposed to add it there. It should be part of the documentation from the project which provides the module.
I am new to both openCV and Android. I have to detect objects in my project. So, I have decided to use ASIFT for the same. However, the code they have given here is very lengthy. It contains lots of C file. It also doesn't have openCV support.
Some search on the SO itself suggested that it is easier to connect the ASIFT code to the openCV library, but I can't figure out how to do that. Can anyone help me by giving some link or by telling the steps that I should use to add ASIFT to my openCv library, which I can further utilize in making my Android application?
Also, I would like to know whether using Android NDK along with JNI to make calls to the C files or using Android SDK along with binary package for my android project(Object Detection) would be a suitable option for me?
Finally , I solved my problem by using the source code given at the website of ASIFT developers. I compacted all the source files together to make my own library using make. I then called the required function from the library using JNI.
It worked for me, but the execution is taking approximate 2 mins on an Android device. Anyone having some idea about ways to reduce the running time ?
They used very simple and slow brute force matching (just for proving of concept). You can use FLANN library and it will help a lot. http://docs.opencv.org/doc/tutorials/features2d/feature_flann_matcher/feature_flann_matcher.html