openCV status - Cinder Forums

Loading...

Cinder Forums

Recent Topics
All Forums
- Search All
- Tags
- Author
- Advanced Search
Search
New Topic

Developing Cinder

andrea

openCV status

in Developing Cinder • 1 year ago

Hi,

I'm about to start a new project which requires computer vision and I was wondering at what point is the openCV development in cinder and whether it's stable and reliable or not.
The project I'm about to start is a massive and really expensive OLED wall therefore I would like to be sure that Cinder really suit to this project.

also it might be a stupid question, but what the different between using the Cinder openCV lib and just openCV?

1

Replies(36)

marcinignac

Re: openCV status

1 year ago

If I were you I wouldn't wait for OpenCV block. OpenCV is just another C++ lib and for me worked seamlessly with Cinder.

Here is explained how use Cinder capture and convert the texture to OpenCV image that can be processed further by the lib: http://forum.libcinder.org/#topic/23286000000057239 . Using this approach I successfully managed to get face tracking working in Cinder. I had no speed issues at all.

Andrea

Re: openCV status

1 year ago

is what I'm doing at the moment and that's why I was wondering what's the point of wrapping openCV.into another c++ lib.

thanks for your reply :]

Did anybody has experienced any issue?

Re: openCV status

1 year ago

Hey - @marcinignac is totally correct. You can definitely use OpenCV no problem already (I have been for a long time myself). However I am finishing up the official CinderBlock - I am intending to be done w/ it in less than 2 weeks. To be honest the bulk of the coding is finished (maybe all of it) but I am doing my best to write some reasonable docs for it.

My recommendation if you want to be compatible with the CinderBlock is to use the object oriented C++ API in OpenCV 2.1. This is their preferred API anyway, and the CinderBlock is designed to be very lightweight - it will just be essentially 2 overloaded functions, toOcv() and fromOcv() which translate between Cinder and OpenCV's types.

Andrea

Re: openCV status

1 year ago

I've already tried OpenCV 2.1, but what exactly the CinderBlock does and why as you said it should translate between Cinder and OpenCV?

Re: openCV status

1 year ago

This is an old version now, but you can see it here:

http://github.com/andrewfb/cinder_public/tree/opencv/blocks/opencv/

http://github.com/andrewfb/cinder_public/blob/opencv/blocks/opencv/samples/ocvVideo/src/ocvVideoApp.cpp

with the CinderBlock, you can write lines like this:

	if( capture.checkNewFrame() ) {
		cv::Mat input( toOcv( capture.getSurface() ) )
                cv::Mat output;
		cv::Sobel( input, output, CV_8U, 1, 0, 3);
		mTexture = gl::Texture( fromOcv( output ) );
	}

-Andrew

Andrea

Re: openCV status

1 year ago

basically it's just to convert the images from the Cinder capture to openCV right?

but why the cinder capture format doesn't match with openCV?

sorry if all the questions above are banal, but I'm still a little bit confused, I just don't get why we should wrap the openCV c++ library into another c++ library.

i also don't get this syntax cv::Mat input( toOcv( capture.getSurface() ) ), is input a function or a particular way to define the input variable?

sansumbrella

Re: openCV status

1 year ago

i also don't get this syntax cv::Mat input( toOcv( capture.getSurface() ) ), is input a function or a particular way to define the input variable?

That's just initializing the variable. In c++, initialization is separate from assignment. We could (probably) also write:

cv::Mat input;

input = cv::Mat( toOcv( capture.getSurface() ) );

However, that would initialize input with some value, then immediately replace it with a new value. We're saving ourselves some CPU usage by initializing the variable with the value we want.

Andrew isn't really wrapping openCV; you're right that it's not something that is really necessary. However, if we want to use openCV and cinder, we'll want a way for the two to share data. That's why Andrew is creating a bridge between the two. You can write your own bridge functions, using the techniques described in the thread Marcin linked to earlier. Andrew is simply streamlining that process, and making it look very clean.

Cinder's image/texture/capture formats are made to be useful in a wide range of applications. I don't know the details of them, so I can't explain thoroughly. However, I assume openCV's types are designed for special openCV uses, and don't have some of the extra utility Cinder's types do (and probably vice-versa). For that reason, they can't be implicitly exchanged one for another.

Andrea

Re: openCV status

1 year ago

thank you for your reply, now everything it's clear, basically it's just a way to make things easier.

now I even get the syntax to initialize the input variable, I would wrongly do it with cv::Mat input ch::Mat( toOcv( capture.getSurface() ) ) but I guess it does like your example above.

Re: openCV status

1 year ago

Just confirming everything @sansumbrella posted is spot on.

Re: openCV status

1 year ago

Hey - checkout the opencv branch, and in there it's in /blocks/opencv

Andrea

Re: openCV status

1 year ago

yep I just deleted my reply :D thanks anyway

Andrea

Re: openCV status

1 year ago

actually I still have an issue.

I've got the latest code from the public repo, I compiled it, open the helloCv example and added /op/local/include/ to the header search paths(xcode) but when I run it it return an error. Why in the header search paths there is $(CINDER_PATH)/blocks/opencv/OpenCV/include which doesn't exist in the ocvHello example?

i686-apple-darwin10-g++-4.2.1: ../../../../../blocks/opencv/OpenCV/lib/libcv.a: No such file or directory
i686-apple-darwin10-g++-4.2.1: ../../../../../blocks/opencv/OpenCV/lib/libcxcore.a: No such file or directory
Command /Developer/usr/bin/g++-4.2 failed with exit code 1

update: I found the libcv and libcxcore libraries in /opt/local/lib/ but they have a different extension "dylib"

Re: openCV status

1 year ago

Hey - there are a number of ways to setup & build OpenCV, but if you need to add /opt/local/include it sounds like you probably built it a different way from the CinderBlock

Did you run across the readme,

http://github.com/andrewfb/cinder_public/tree/opencv/blocks/opencv/docs/

This gives you the command line we're expecting you to build with. Part of why we do it this way is so that going forward, the CinderBlock can contain precompiled libraries so most people won't have to mess with building OpenCV itself (which as you're discovering, can be quite painful :)).

-Andrew

Andrea

Re: openCV status

1 year ago

I see, you compile opencv inside cinder, I just installed it with macport, I guess I'm going to compile it as you suggest, thank you.

PS: the "." and the end of the command freaked me out(I didn't catch it at the beginning) :D

Andrea

Re: openCV status

1 year ago

I'm having a lot of problem with compiling openCV with your options, is there a way to use the OpenCV version installed with macport? I find it much easier to do it though macport, at the end I should only point to the dylib files instead the .a, am I wrong?

when i try to compile opencv it fails, seems there is a problem with lavcodec which should be part of ffmpeg and if I install it with macport nothing change, if I try to compile it it fails.

Re: openCV status

1 year ago

Hi - do you have the 10.5 SDK on your machine? Mind posting a few of the errors you're seeing when compiling? Are you using the exact command line string from the readme?

Part of the reason we don't do the macports style setup is that it can complicate the distribution of your application. In certain scenarios it also requires someone to have root access to their machine for development, which not everyone does.

Distribution of your app can be a problem any time you use a .dylib (or a .dll on Windows) or when you use a -l linker flag in GCC (instead of the fully qualified path). On the Mac you can use some tricks to alleviate it but Cinder is designed to statically link whenever possible to avoid these issues.

Andrea

Re: openCV status

1 year ago

Linking CXX static library ../../lib/libcvhaartraining.a
[ 91%] Built target cvhaartraining
Scanning dependencies of target createsamples
[ 91%] Building CXX object apps/haartraining/CMakeFiles/createsamples.dir/createsamples.o
cc1plus: warning: /Users/Q/cinder_public/blocks/opencv/OpenCV/src/cvaux/_cvaux.h.gch/cvaux_RELEASE.gch: created and used with differing settings of '-mmacosx-version-min='
Scanning dependencies of target haartraining
[ 91%] Building CXX object apps/haartraining/CMakeFiles/haartraining.dir/haartraining.o
Linking CXX executable ../../bin/opencv_createsamples
ld: library not found for -lavcodec
collect2: ld returned 1 exit status
ld: library not found for -lavcodec
collect2: ld returned 1 exit status
lipo: can't open input file: /var/folders/xJ/xJ8qnLjWHoSchoMIyq8kZU+++TI/-Tmp-//ccOA4Mj7.out (No such file or directory)
make[2]: *** [bin/opencv_createsamples] Error 1
make[1]: *** [apps/haartraining/CMakeFiles/createsamples.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....
[ 91%] Building CXX object src/cvaux/CMakeFiles/cvaux.dir/cvbgfg_common.o
[ 91%] Building CXX object src/cvaux/CMakeFiles/cvaux.dir/cvbgfg_gaussmix.o
Linking CXX executable ../../bin/opencv_haartraining
cc1plus: warning: /Users/Q/cinder_public/blocks/opencv/OpenCV/src/cvaux/_cvaux.h.gch/cvaux_RELEASE.gch: created and used with differing settings of '-m32'
cc1plus: warning: /Users/Q/cinder_public/blocks/opencv/OpenCV/src/cvaux/_cvaux.h.gch/cvaux_RELEASE.gch: created and used with differing settings of '-m32'
ld: library not found for -lavcodec
collect2: ld returned 1 exit status
ld: library not found for -lavcodec
collect2: ld returned 1 exit status
lipo: can't open input file: /var/folders/xJ/xJ8qnLjWHoSchoMIyq8kZU+++TI/-Tmp-//cc8sHGww.out (No such file or directory)
make[2]: *** [bin/opencv_haartraining] Error 1
make[1]: *** [apps/haartraining/CMakeFiles/haartraining.dir/all] Error 2
...
...
...
/usr/bin/ranlib: for architecture: x86_64 file: ../../lib/libcvaux.a(enmin.o) has no symbols
/usr/bin/ranlib: for architecture: x86_64 file: ../../lib/libcvaux.a(extendededges.o) has no symbols
[ 99%] Built target cvaux
make: *** [all] Error 2

as I said I think the problem is with this lavacoded library.

I also figured out how to use the macport version but at the moment is compiled for x86_64 and not compatible with my cinder app, I don't really know why and at this point I'd prefer to stay with your standard.

thanks for your support.

Andrea

Re: openCV status

1 year ago

I'm also trying to compile it in windows and it failed, what do you mean with:

"* Switch the runtime of the opencv_lapack target to Multithreaded Debug" and
"Disable debug symbols on the Release targets"

Re: openCV status

1 year ago

Hey - sorry, at work, so I'll have to look at this in more detail tonight. However, try this on the Mac instead:

cmake -D CMAKE_BUILD_TYPE=RELEASE -D BUILD_PYTHON_SUPPORT=OFF -D BUILD_NEW_PYTHON_SUPPORT=OFF -D BUILD_EXAMPLES=OFF -D BUILD_TESTS=OFF -D BUILD_SHARED_LIBS=OFF -D CMAKE_C_FLAGS="-mmacosx-version-min=10.5 -m32" -D CMAKE_OSX_DEPLOYMENT_TARGET=10.5 -D CMAKE_OSX_SYSROOT=/Developer/SDKs/MacOSX10.5.sdk -D CMAKE_OSX_ARCHITECTURES="i386" -D CMAKE_CXX_FLAGS="-mmacosx-version-min=10.5 -m32" -D OPENCV_EXTRA_C_FLAGS="-mmacosx-version-min=10.5" .

As far as the Windows stuff, you'll need to open the .vcproj files that cmake generates and modify the runtime library of opencv_lapack to link against the Multithreaded Debug runtime (instead of Multithreaded Debug DLL) in its Debug configuration. If you haven't done this in VC before, it's in your project's properties, under the Code Generation section of the C/C++ category. You have to do this manually due to a problem with OpenCV's interaction with CMake.

Andrea

Re: openCV status

1 year ago

thanks for your clarification about visual studio, hope that will sort out the issue.

I tried the command above on osx and it didn't work just like the other one.

Re: openCV status

1 year ago

What version of CMake are you running? I've just determined that CMake had a bug in versions earlier than 2.8 which cause OpenCV to always build 64-bit on Snow Leopard regardless of other commands.

Andrea

Re: openCV status

1 year ago

cmake version 2.8.2

might this one be the case?

Re: openCV status

1 year ago

Hmm - what happens if you run make a second time? I know that's sorta absurd, but it helped over here. Apparently OpenCV has some build bugs which specifically affect Snow Leopard - working on tracking that down. I do have it building, and once this is a CinderBlock most users won't need to build it - let me know if you need me to zip up the .a's for you in the meantime.

a.stellato

Re: openCV status

1 year ago

Checked out this block today, openCV built fine with the default instructions on a mac pro with snow leopard. Setting up Cinder was painless for me, but ocvSlowMo needed some tweaked build paths in order to compile.

Tried to add cvCanny to the ocvVideo example, but couldn't get it to work. Turned the input into greyscale and it still complained. Hmmm . . .

Love the bridge from native Cinder to cvMat. Good job so far!

sansumbrella

Re: openCV status

1 year ago

Hey,

I had a similar experience with cv::Canny.

If you want to use cv::Canny (which is recommended over cvCanny), make sure you generate your source image with a color conversion. Converting to grayscale in place didn't reduce the channels in the image to 1, but it will create a 1-channel image if you provide a separate image to write to.

cv::Mat input, gray, edges;
//get input from somewhere
...
//create a 1-channel image
cv::cvtColor( input, gray, CV_RGB2GRAY );
cv::Canny( gray, edges, 10, 100, 3 );

a.stellato

Re: openCV status

1 year ago

@sansumbrella - That code works fine. What's funny is that I coded exactly the same, except by habit I was using cvCvtColor and cvCanny, instead of the calls from the cv namespace. Thanks!

sansumbrella

Re: openCV status

1 year ago

@a.stellato Glad it works.

Andrea

Re: openCV status

1 year ago

I tried to run make twice and it returned:

[ 99%] Built target cvaux
Linking CXX executable ../../bin/opencv_createsamples
Linking CXX executable ../../bin/opencv_haartraining
Linking CXX executable ../../bin/opencv_performance
Linking CXX executable ../../bin/opencv_traincascade
ld: library not found for -lavcodec
collect2: ld returned 1 exit status
ld: library not found for -lavcodec
collect2: ld returned 1 exit status
ld: library not found for -lavcodec
collect2: ld returned 1 exit status
ld: library not found for -lavcodec
collect2: ld returned 1 exit status
make[2]: *** [bin/opencv_traincascade] Error 1
make[2]: *** [bin/opencv_performance] Error 1
make[1]: *** [apps/traincascade/CMakeFiles/traincascade.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....
make[2]: *** [bin/opencv_createsamples] Error 1
make[1]: *** [apps/haartraining/CMakeFiles/performance.dir/all] Error 2
make[1]: *** [apps/haartraining/CMakeFiles/createsamples.dir/all] Error 2
make[2]: *** [bin/opencv_haartraining] Error 1
make[1]: *** [apps/haartraining/CMakeFiles/haartraining.dir/all] Error 2
make: *** [all] Error 2

ah just to clarify, I'm using the latest version of cinder, opencv and cmake

sansumbrella

Re: openCV status

1 year ago

Hey,

I received a number of those errors when building, too (on mac 10.6). However, openCV was still built, only without some extra parts. In your OpenCV folder do you see lib/libcv.a or any .a files? If you do, then you should be able to proceed.

If not, I would look at the openCV resources. The OpenCV install guide should lead you in the right direction. If that fails, there might be some discussion in the openCV user group which you can look up.

Andrea

Re: openCV status

1 year ago

I've just found a work around, I compiled it with xcode.

http://giesler.biz/~bjoern/blog/?p=183

btw I'm running the samples and the face detection is incredibly fast :]

m9dfukc

Re: openCV status

1 year ago

hi,

I had exactly the same problems as diodo,

running snow leopard with cmake 2.8.2 and actual opencv 2.1 svn. However, I compiled it a second time and beside some extra stuff everything compiled fine so I was able to link the libcv.a, libml.a ....

I also freaked out with the the "." and the end of the command ... took me half a day until I realized that this is needed too!

Andrea

Re: openCV status

1 year ago

sorry guys but i still have problems to compile it, this time in windows.

as Andrew said I switched the runtime of the opencv_lapack target to Multithreaded debug, but I couldn't find out how to disable the debug symbols on the release targets.

Without have done this step the compiler can't open a few files like videoinput.h, highgui210d.lib, I guess this depends on those settings.

Andrea

Re: openCV status

1 year ago

ok I still have a problem even in Xcode, I created a brand new application in the opencv samples directory with exactly the same project settings as ocvVideo(which I can compile), I've also included thje CinderOpenCV.h by creating a new group and sub groups(like ocvVideo even if I don't really understand why) but when I try to compile it I have a few errors in the linker, I've been trying to solve this problem for the past 2 days, but now I'm definitely lost. I don't really understand how it includes the library (.a) files, int the ocvVideo project settings the library search path is empty, and that might be the problem with my application. How does the demo includes the opencv library?

I also notice that in the sample header search directory there is ../include which doesn't point to no where.

I apologize if this thread is endless, but I'm experiencing a lot of different issues with opencv.

thanks for you help.

Re: openCV status

1 year ago

Hey,

I've had some problems with it too. I used TinderBox to setup the project somewhere in my user directory and have just been trying to setup a basic video capture routine.


cv::Mat input( toOcv( capture.getSurface() ) )

When I added this code I got the following errors

Undefined symbols:
  "cv::fastFree(void*)", referenced from:
      cv::Mat::release()    in ColourDanceApp.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

I broke down the above code into


		Surface frame;
		frame = mCap.getSurface();
		cv::Mat matrix;
		matrix = toOcv( frame );
		cv::Mat input( matrix );

And found I got this error at:


		cv::Mat matrix;

(and a whole bunch of errors)

Its been awhile since I've done any C++ but I'm concluding from this that its a project setup problem as the code it mostly taken from the OpenCV examples.

The tutorial on how to setup a project is handy but I noticed there are no instructions for how to add Blocks to project one setups up oneself?

Andrea

Re: openCV status

1 year ago

Hi,

you are probably missing something in the project settings, assuming you are using Xcode(can't remember how to set it in VS at the moment) you have to go to "Project" > "Edit active target" > "Other linker flags" and add the opencv library for BOTH debug(it uses libcinder_d.a that's why they are different) and release, you should have something like this:

debug
$(CINDER_PATH)/lib/libcinder_d.a
$(CINDER_PATH)/blocks/opencv/lib/macosx/libcv.a
$(CINDER_PATH)/blocks/opencv/lib/macosx/libcxcore.a

release
$(CINDER_PATH)/lib/libcinder.a
$(CINDER_PATH)/blocks/opencv/lib/macosx/libcv.a
$(CINDER_PATH)/blocks/opencv/lib/macosx/libcxcore.a

you also need to edit the project settings, "Project" > "edit project settings" > "header search paths", in this case you can do it for both configurations at the same time.

"$(CINDER_PATH)/blocks/opencv/include"

ah btw if you search in the forum there are several posts regarding opencv and how to get it up and running which is basically what I wrote above.

Re: openCV status

1 year ago

Hey,

Thanks for that! Seems to have fixed the problem. I did search the forums for an answer but didn't manage to find this solution. It would be really handy to have this sort of knowledge distilled into a public Wiki somewhere. I'd be willing to help with the content and document solutions to any road blocks I come across being a n00b and all :) was planning on doing some blogging about it anyway.

© 2012 ZOHO Corp.
All Rights Reserved.
Privacy
Terms & Conditions
RSS
Powered by