Is Neon Optimization enabled by default in Official OpenCV 3.4.4 prebuilt android libraries?

asked 2018-11-23 00:30:16 -0500

Kafan gravatar image

updated 2018-11-23 00:30:28 -0500

I need to know this as my online search never provided me the answer.

a) Is the NEON optimization enabled in the default official precompiled android Opencv libraries? If No, then is there any reason why the official team does not compile it with it enabled?

b) If an android device does not have support for NEON optimization (I think some armv7a processor doesn't support it). Does it crash or fallback to non-neon algorithm?

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Hello Kafan, I have investigated this way and I haven't found good information.

However, I'm with Opencv 3.2.0 with NDK 15c and STL C++_Static, could you tell me your compile configuration, please ?

If you found any solutions to compile with Neon Optimization, give an answer you'll help many peoples.

Thank you advance, Regards.

Simontraww gravatar imageSimontraww ( 2018-11-23 01:54:16 -0500 )edit
2
LBerger gravatar imageLBerger ( 2018-11-23 03:33:24 -0500 )edit

@LBerger could you tell something please because i don't understand how to do that with your pull request.

Thank you for helping !!

Simontraww gravatar imageSimontraww ( 2018-11-23 08:20:40 -0500 )edit

@LBerger. Thanks for the link. Looks like the cmake config does enable NEON on v7a and v8a.

@Simontraww If you want to check for yourself go to the below link and search with "CPU/HW features" and notice the NEON status for different "Target"

https://pullrequest.opencv.org/buildbot/builders/precommit_pack_android/builds/10792/steps/build%20sdk/logs/stdio

Kafan gravatar imageKafan ( 2018-11-23 11:15:31 -0500 )edit

@Kafan Thanks for the tips that very

INFO COMPILATION : OPENCV 3.4.4 with NEON because the 4.0.0 said some errors with some headers.

However, i've meet a few undefined reference, such as :

error: undefined reference to 'cv::read' error: undefined reference to 'cv::write' error: undefined reference to 'cv::KeyPointsFilter::retainBest [...] Do you have an idea ? Thanks

Simontraww gravatar imageSimontraww ( 2018-11-26 08:18:43 -0500 )edit