OpenCV C++ listing files in a directory? - c++

I am developing a C++ project with OpenCV. I was thinking to use Boost library to do a simple ls, but I would like to follow opencv standars..
How can I do a cross plataform listing files with opencv?

OpenCV is not created to solve such problems - you have to use another API. Look at this stacloverflow discussion. It seems that it's cross-platform.

There is a header
opencv2\contrib\contrib.hpp
It contains a class called Directory and few functions like GetListFiles,
GetListFolders and GetListFilesR.
You can try it out, but it's not available in Opencv3.

Related

ArUco program from scratch

I'm using the ArUco library with OpenCV (more information here) but I can't find a way to build and run a program from scratch.
Once I installed the library I have access to different examples but if I want for instance to create a new file and add the library headers inside it, how can I compile and run it ? (with a command line or IDE, anything is fine)
Thank you
I sent and email to the library's author and he added clear instructions at the end of the project webpage :)
It seems you need to learn how to use your IDE's, compilation tools and general compilation basic stuff. This is not a question related to Aruco, or mostly any other tags you have set.
Try to lean CMake first, 'cause Aruco compilation is based on CMake: http://www.cmake.org/
You can start by just editing the aruco_simple example.
For a IDE that works right away with CMake you can try either Qt Creator >3.1 or KDevelop. Both free.

c++/objective-c use octave withouth installed

I'm currently working on a project for my university, where I have to develop an iOS app. For this I would like to work with octave. My question is, if it's possible to use my octave code as a c++ library without having octave installed, which I just can include to my Objective-C project and give the input to the library, which computes the result and return the output to my project.
I already searched the web, but I couldn't find anything :/
Best regards,
Carsten

How to call Matlab functions from Visual studio mfc project?

What I have done is following the guidline in this
website
Now, I want to use some functions like rgb2gray() and imresize()... but I dont know how to use them, or I dont know which header file should I include in my project?
I have tried other way by creating a C++ shared-library in Matlab, then used it in VS 2012, but I could not add the DLL file to my project when I added new references. it is like that:
Please help me!
thanks in advance.
If you really want to call Matlab inside visual-studio, there are two ways:
Distribute MATLAB into independent shared library: check out my blog-post on how to do this (with detail steps and example).
Call MATLAB Engine directly: Refer to another blog of mine for more info.
On the other hand, it seems that you don't need to call Matlab to achieve your goal. OpenCV library will offer functions similar to rgb2gray() and imresize().

Adding third party libraries to an OpenCV project on Xcode

I am new to the XCode environment so apologies if this sounds trivial.
I am trying to use a third party library using for OpenCV that helps me do some blob analysis, CCL etc. Hosted here
I have searched a lot but there doesn't seem to be much documentation on how to go about adding and using these new libraries. I am using XCode 4.5.2, OpenCV 2.4.2.
When I simply add all the header files to the project folder and #include them in the source code, it fails to compile. I have also tried adding the "Header Paths" but it doesn't help. What am I missing?
I have tried to follow the instructions (compiling it using the terminal but it doesn't compile too) I am not clear on how or when exactly to use CMAKE.
Any help will be appreciated. Thank you.
I would suggest you using CvBlob on google code which is different from the one on willowgarage, I have got recently confused with this so take a look at this question for alternative blob analysis libraries.
Moreover, CvBlob has also a good support community here. (Search on "[cvblobslib]" or on "[blob] [opencv]")
Try this: cvBlob: OSX installation
Once you get it compiled, you need to include the library under Link Binary with Libraries in Build Phases. (This screenshot shows the core, imgproc, and highgui libraries. Your cvBlob library would go in the same place.)

How do I zip a directory of files using C++?

I'm working on a project using C++, Boost, and Qt. I understand how to compress single files and bytestreams using, for example, the qCompress() function in Qt.
How do I zip a directory of multiple files, including subdirectories? I am looking for a cross-platform (Mac, Win, Linux) solution; I'd prefer not to fire off a bunch of new processes.
Is there a standard way to combine bytestreams from multiple files into a zipped archive, or maybe there is a convenience function or method that would be available in the Boost iostream library?
Many thanks for the assistance.
Update: The QuaZip library looks really great. There is an example in the download package (in the "tests" dir) that shows very clearly how to zip up a directory of files.
Update 2: After completing this task on my Linux build environment, I discovered that QuaZip doesn't work at all with the Visual Studio compiler. It may be possible to tackle all those compiler errors, but a word of caution to anyone looking down this path.
I have found the following two libraries:
ZipIOS++. Seems to be "pure" C++. They don't list Windows explicitly as a supported platform. So i think you should try your luck yourself.
QuaZIP. Based on Qt4. Actually looks nice. They list Windows explicitly (Using mingw). Apparently, it is a C++ wrapper for [this] library.
Ah, and of course, i have ripped those sites from this Qt Mailinglist question about Zipping/Unzipping of directories :)
Just for the record...
Today, I needed to do something very similar in Visual C++. (Though wanted to maintain the possibility to compile the project on other platforms; however preferred not to adopt Qt just for this purpose.)
Ended up using the Minizip library. It is written in plain C, but devising a simple C++ wrapper around it was a breeze, and the end result works great, at least for my purposes.
I have built a wrapper around minizip adding some features that I needed and making it nicer to use it. Is does use the latest c++11 and is developed using Visual Studio 2013, so it should work out-of-the-box for you.
There's a full description here: https://github.com/sebastiandev/zipper
you can zip entire folders, streams, vectors, etc. Also a nice feature is doing everything entirely in memory.
Poco::Zip is also a choice, it has clearly documentation and some code for demo.
Poco::Zip Document
system("zip myarchive.zip *");
I tried QuaZIP 0.4.3 on Windows with VisualStudio 2010 -- there are still issues but can be resolved easily.
To build with VS:
Use CMake to configure and generate VS solution for QuaZIP.
Open soltion with VS and build -- you'll first notice that it can't find 'zlib.h'.
Open preferences for quazip project and add path to Qt's copy of Zlib to C/C++->General->Additional Include Directories: $(QTDIR)/src/3rdparty/zlib.
Rebuild again and you'll get lots of warnings and one error C2491: dllimport static issue on QuaZipFile::staticMetaObject.
This is because QuaZipFile is declared like "class QUAZIP_EXPORT QuaZipFile" and QUAZIP_EXPORT needs to resolve to Q_DECL_EXPORT for dll and to Q_DECL_IMPORT for application, based on whether QUAZIP_BUILD is defined or not. When building QuaZIP QUAZIP_BUILD should be defined but isn't -- configuration process defines in error completely useless "quazip_EXPORTS" instead.
To fix, just remove "quazip_EXPORTS" from all build configurations and add QUAZIP_BUILD instead -- QuaZIP will now build fine.