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OpenCv Android only native

asked 2017-09-30 07:24:21 -0500


I am using the Android opencv sdk in my project, and everything is good but size. I know there are ways to build for diferent platforms, shrink size and so on, but my question is of different nature.

There is a thing I don't understand, when I build the library in Android Studio using cmake I link it to libraries provided from environment variable in cmake which opencv exposes (version 3.2) , for this I downloaded opencv native sdk for android and made a separate project in Android Studio, now the size is big because the is somehow linked to my library so, but as I think of it libopencv_java comes for the java code which comes with opencv sdk, and I don't usye any of the sdk java code, I do everything in C/C++, and have defined my own JNI code to interact with that c/c++ methods. Now the question, can I, in my case reduce all the size to maybe 2-3 modules ( core, imageproc and one more maybe), because I need only those.

I know a bit of c/c++ syntax but the linking static, shared and so one all this things a bit in the fog for me.

Can you please help?


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answered 2017-09-30 08:13:27 -0500

tham gravatar image

updated 2017-09-30 08:13:51 -0500

You can compile the library by yourself, built them as static lib and disable opencv_world.This post has the details

Supplement :

  1. Switch off the modules you do not need
  2. Switch off BUILD_opencv_world(maybe step 2 could be skiped)
  3. Switch off BUILD_SHARED_LIBS
  4. I build opencv3.3 with tbb and carotene, they works fine on android phone

After you run mingw32-make install, link to the library you need, the order of linking is crucial, try to change their orders if you got a lot of link errors.

My example(I build the project by qmake):

LIBS += $${CV_LIB_PATH}/libopencv_world.a

LIBS += $${OPENCV_3RD_LIBS}/liblibtiff.a
LIBS += $${OPENCV_3RD_LIBS}/liblibjpeg.a
LIBS += $${OPENCV_3RD_LIBS}/liblibjasper.a
LIBS += $${OPENCV_3RD_LIBS}/liblibpng.a
LIBS += $${OPENCV_3RD_LIBS}/libIlmImf.a

LIBS += $${OPENCV_3RD_LIBS}/libcpufeatures.a
LIBS += $${OPENCV_3RD_LIBS}/libtegra_hal.a
LIBS += $${OPENCV_3RD_LIBS}/liblibwebp.a
LIBS += $${OPENCV_3RD_LIBS}/liblibprotobuf.a
LIBS += $${OPENCV_3RD_LIBS}/libtbb.a

I link with opencv_world because I do not want to fiddle with the link order

Example project--Light detector, build with Qt5 and opencv3.3, show you how to build cross-platform computer vision app with Qt5 and opencv.

ps : if you are familiar with tensorflow, please lend me a hand--Turn is_training of batchnorm(TensorFlow) to False, thanks.

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Thanks for the answer, it doesn't really answer my question, but you gave me some ideas of things to check.

p.s.: not familiar with tensor flow.

Alekshandru gravatar imageAlekshandru ( 2017-10-01 02:16:27 -0500 )edit
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Last updated: Sep 30 '17