OpenCV-2.4.9-android-sdk

|_ apk

|   |_ OpenCV_2.4.9_binary_pack_armv7a.apk

|   |_ OpenCV_2.4.9_Manager_2.18_XXX.apk

|

|_ doc

|_ samples

|_ sdk

|    |_ etc

|    |_ java

|    |_ native

|          |_ 3rdparty

|          |_ jni

|          |_ libs

|               |_ armeabi

|               |_ armeabi-v7a

|               |_ x86

|

|_ LICENSE

|_ README.android

Get the OpenCV4Android SDK

1. Go to the OpenCV download page on SourceForge and download the latest available version. Currently it’s OpenCV-2.4.9-android-sdk.zip.

2. Create a new folder for Android with OpenCV development. For this tutorial we have unpacked OpenCV SDK to the C:\Work\OpenCV4Android\directory.

   Note

   Better to use a path without spaces in it. Otherwise you may have problems with ndk-build.

3. Unpack the SDK archive into the chosen directory.

   You can unpack it using any popular archiver (e.g with 7-Zip):

   

   On Unix you can use the following command:

   unzip ~/Downloads/OpenCV-2.4.9-android-sdk.zip
   

Import OpenCV library and samples to the Eclipse

1. Start Eclipse and choose your workspace location.

   We recommend to start working with OpenCV for Android from a new clean workspace. A new Eclipse workspace can for example be created in the folder where you have unpacked OpenCV4Android SDK package:

   

2. Import OpenCV library and samples into workspace.

   OpenCV library is packed as a ready-for-use Android Library Project. You can simply reference it in your projects.

   Each sample included into the OpenCV-2.4.9-android-sdk.zip is a regular Android project that already references OpenCV library. Follow the steps below to import OpenCV and samples into the workspace:

   Note

   OpenCV samples are indeed dependent on OpenCV library project so don’t forget to import it to your workspace as well.

   • Right click on the Package Explorer window and choose Import... option from the context menu:

     

   • In the main panel select General ‣ Existing Projects into Workspace and press Next button:

     

   • In the Select root directory field locate your OpenCV package folder. Eclipse should automatically locate OpenCV library and samples:

     

   • Click Finish button to complete the import operation.

   After clicking Finish button Eclipse will load all selected projects into workspace, and you have to wait some time while it is building OpenCV samples. Just give a minute to Eclipse to complete initialization.

   Warning

   After the initial import, on a non-Windows (Linux and Mac OS) operating system Eclipse will still show build errors for applications with native C++ code. To resolve the issues, please do the following:

   Open Project Properties -> C/C++ Build, and replace “Build command” text to "${NDKROOT}/ndk-build" (remove .cmd at the end).

   Note

   In some cases the build errors don’t disappear, then try the following actions:

   • right click on OpenCV Library project -> Android Tools -> Fix Project Properties, then menu Project -> Clean... -> Clean all
   • right click on the project with errors -> Properties -> Android, make sure the Target is selected and is Android 3.0 or higher
   • check the build errors in the Problems view window and try to resolve them by yourselves

   

   Once Eclipse completes build you will have the clean workspace without any build errors:

   

Running OpenCV Samples

At this point you should be able to build and run the samples. Keep in mind, that face-detection and Tutorial 2 - Mixed Processing include some native code and require Android NDK and NDK/CDT plugin for Eclipse to build working applications. If you haven’t installed these tools, see the corresponding section of Introduction into Android Development.

Well, running samples from Eclipse is very simple:

• Connect your device with adb tool from Android SDK or create an emulator with camera support.

  • See Managing Virtual Devices document for help with Android Emulator.
  • See Using Hardware Devices for help with real devices (not emulators).

• Select project you want to start in Package Explorer and just press Ctrl + F11 or select option Run ‣ Run from the main menu, or click Run button on the toolbar.

  Note

  Android Emulator can take several minutes to start. So, please, be patient.

• On the first run Eclipse will ask you about the running mode for your application:

  

• Select the Android Application option and click OK button. Eclipse will install and run the sample.

  Chances are that on the first launch you will not have the OpenCV Manager package installed. In this case you will see the following message:

  

  To get rid of the message you will need to install OpenCV Manager and the appropriate OpenCV binary pack. Simply tap Yes if you haveGoogle Play Market installed on your device/emulator. It will redirect you to the corresponding page on Google Play Market.

  If you have no access to the Market, which is often the case with emulators - you will need to install the packages from OpenCV4Android SDK folder manually. See How to select the proper version of OpenCV Manager for details.

  1	<Android SDK path>/platform-tools/adb install <OpenCV4Android SDK path>/apk/OpenCV_2.4.9_Manager_2.18_armv7a-neon.apk

  Note

  armeabi, armv7a-neon, arm7a-neon-android8, mips and x86 stand for platform targets:

  • armeabi is for ARM v5 and ARM v6 architectures with Android API 8+,
  • armv7a-neon is for NEON-optimized ARM v7 with Android API 9+,
  • arm7a-neon-android8 is for NEON-optimized ARM v7 with Android API 8,
  • mips is for MIPS architecture with Android API 9+,
  • x86 is for Intel x86 CPUs with Android API 9+.

  If using hardware device for testing/debugging, run the following command to learn its CPU architecture:

  adb shell getprop ro.product.cpu.abi
  

  If you’re using an AVD emulator, go Window > AVD Manager to see the list of availible devices. Click Edit in the context menu of the selected device. In the window, which then pop-ups, find the CPU field.

  You may also see section How to select the proper version of OpenCV Manager for details.

  When done, you will be able to run OpenCV samples on your device/emulator seamlessly.

• Here is Sample - image-manipulations sample, running on top of stock camera-preview of the emulator.