How do I build OpenCV with TBB?

问题

I'm trying and failing to make opencv_traincascade use multiple threads. The only documentation I can find says to "build OpenCV with TBB". I'm not sure if I'm failing to successfully build OpenCV with TBB, or whether there's some flag I need to set for opencv_traincascade.

I've downloaded the OpenCV version 2.3.1 windows superpack and tbb40_20111003oss_win.zip, which I extracted to C:\tbb40_20111003oss. I then generated VC8 .sln and .proj files using CMake, setting

WITH_TBB: ON

TBB_INCLUDE_DIR:PATH=C:\tbb40_20111003oss\include

TBB_LIB_DIR:PATH=C:/tbb40_20111003oss/lib/intel64/vc8

OpenCV then builds without errors, but when I run opencv_traincascade it's singlethreaded. Does anyone know what I'm doing wrong?

回答1:

If you are on Mac you can do this with homebrew:

brew tap homebrew/science
brew install opencv --with-tbb

Or if you have already installed with homebrew:

brew uninstall opencv
brew install opencv --with-tbb

Also, the info command tells you about other flags you might be interested in, e.g. --with-java

brew info opencv

回答2:

I know this is an old thread but I think the problem is that you are using Traincascade with Haart feature insdead of using with the LBP features which uses integer instead of floating point and are working 3 times faster.

See the comment in this question for more information from the author about this. Quick summary: Haart training is difficult to paralelize but LBP is much easier and take advantage of a lot of processors.

Hope it help!

回答3:

Try setNumThreads(), with the number of your processor cores as parameters. There is a helper function to find the optimum number of threads (equals the number of cores), but I cannot remember it.

And make sure you also rebuild the train_cascade exe

回答4:

For linux, do:

cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D WITH_TBB=ON BUILD_TBB=ON ..

回答5:

Instructions here: http://devel-open.blogspot.com.ar/2012/06/instalando-opencv-240-en-ubuntu.html

回答6:

After building the tbb binaries, make sure your path is correctly directing your executable to the tbb dlls. It is possible that you are loading the non-tbb dlls (this happened to me) and these will provide no multithreading.

回答7:

Also, one touch point is the installation of Intel TBB on the system:

$ sudo apt-get install libtbb-dev

来源：https://stackoverflow.com/questions/7994261/how-do-i-build-opencv-with-tbb

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OpenCV

tbb