Facedetection

OpenCV for face detection

Implement face detection sample on Android Studio

Using the OpenCV4Android SDK OpenCV4Android SDK package enables development of Android applications with use of OpenCV library. The structure of package contents looks as follows:

OpenCV-2.4.13-android-sdk
|_ doc
|_ samples
|_ sdk
|    |_ etc
|    |_ java
|    |_ native
|          |_ 3rdparty
|          |_ jni
|          |_ libs
|               |_ armeabi
|               |_ armeabi-v7a
|               |_ x86
|
|_ LICENSE
|_ README.android

Modify the Android.mk and Application.mk You should choose the right hardware platform version, just like armeabi-v7a etc.

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

OPENCV_CAMERA_MODULES:=on
OPENCV_INSTALL_MODULES:=on
OPENCV_LIB_TYPE:=SHARED
ifdef OPENCV_ANDROID_SDK
  ifneq ("","$(wildcard $(OPENCV_ANDROID_SDK)/OpenCV.mk)")
    include ${OPENCV_ANDROID_SDK}/OpenCV.mk
  else
    include ${OPENCV_ANDROID_SDK}/sdk/native/jni/OpenCV.mk
  endif
else
  include $(LOCAL_PATH)/../java/native/jni/OpenCV.mk
endif

LOCAL_SRC_FILES  := DetectionBasedTracker_jni.cpp
LOCAL_C_INCLUDES += $(LOCAL_PATH)
LOCAL_LDLIBS     += -llog -ldl

LOCAL_MODULE     := detection_based_tracker



include $(BUILD_SHARED_LIBRARY)

APP_STL := gnustl_static
APP_CPPFLAGS := -frtti -fexceptions
APP_ABI := armeabi-v7a
APP_PLATFORM := android-23

Set up the AIDL configuration file Moving the OpenCVEngineInterface.aidl from java/org/opencv/engine/ to /src/main/aidl/engine/ This Class provides a Java interface for OpenCV Engine Service. It's synchronous with native OpenCVEngine class.
Config the NDK build Add some source in the file of build.gradle (app/src)

//禁止自带的ndk功能
    sourceSets.main.jniLibs.srcDirs = ['src/main/libs']

    externalNativeBuild{
        ndkBuild {
            path "src/main/jni/Android.mk"
        }
    }

Camera Permission Setting Add the Camera Permission into the AndroidManifest.xml

<uses-permission android:name="android.permission.CAMERA"/>

    <uses-feature android:name="android.hardware.camera"/>
    <uses-feature android:name="android.hardware.camera.autofocus"/>
    <uses-feature android:name="android.hardware.camera.front"/>
    <uses-feature android:name="android.hardware.camera.front.autofocus"/>

Modify the FdActivity java source to add the verification of Camera permission

...
private void verifyCameraPermission() {
        int permission = checkSelfPermission(Manifest.permission.CAMERA);
        if (permission != PackageManager.PERMISSION_GRANTED){
            requestPermissions(new String[] {Manifest.permission.CAMERA}, 1);
        }
    }
...
public void onCreate(Bundle savedInstanceState) {
        Log.i(TAG, "called onCreate");
        super.onCreate(savedInstanceState);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

        setContentView(R.layout.face_detect_surface_view);

        //add camera permission
        verifyCameraPermission();

        mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.fd_activity_surface_view);
        mOpenCvCameraView.setVisibility(CameraBridgeViewBase.VISIBLE);
        mOpenCvCameraView.setCvCameraViewListener(this);
    }
...