Super simple integration of HMS ml kit to realize parent control

Preface

Have app developers received feedback from parents in the background ？ Hope to provide a switch , Take some measures to protect children's eyes , Because now the myopia rate of children is getting higher and higher , It has a lot to do with them staring at the screen closely for a long time . Recently, an overseas customer has integrated ML kit To prevent children's eyes from getting too close to the screen , Or parental control functions that play games for too long .

scene

Parents need this function to prevent children's eyes from getting too close to the screen , Or children spend too much time watching the screen .

Preparation before development

At the project level gradle Add Huawei maven warehouse

open AndroidStudio Project level build.gradle file

Incrementally add the following maven Address ：

buildscript {
     {        
        maven {url 'http://developer.huawei.com/repo/'}
    }    
}
allprojects {
    repositories {       
        maven { url 'http://developer.huawei.com/repo/'}
    }
}

At the application level build.gradle Inside plus SDK rely on

dependencies {
    implementation 'com.huawei.hms:ml-computer-vision-face:1.0.4.300'
    implementation 'com.huawei.hms:ml-computer-vision-face-shape-point-model:1.0.4.300'
    implementation 'com.huawei.hms:ml-computer-vision-face-emotion-model:1.0.4.300'
    implementation 'com.huawei.hms:ml-computer-vision-face-feature-model:1.0.4.300'
}

stay AndroidManifest.xml In the file, apply for a camera 、 Access to network and storage rights

<uses-feature android:name="android.hardware.camera" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.hardware.camera.autofocus" />
<uses-permission android:name="android.permission.WAKE_LOCK" />

Dynamic permission application

 Dynamic permission application 
if (!(ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED)) {
    requestCameraPermission();
}

Key steps in code development

Create a human face analyzer .

MLFaceAnalyzer analyzer = MLAnalyzerFactory.getInstance().getFaceAnalyzer();

establish LensEngine Examples are used for face detection in video streams , This class is composed of ML Kit SDK Provide , Used to capture the camera's dynamic video stream and pass it to the analyzer .

LensEngine mLensEngine = new LensEngine.Creator(getApplicationContext(), analyzer)
        .setLensType(LensEngine.BACK_LENS)
        .applyDisplayDimension(640, 480)
        .applyFps(30.0f)
        .enableAutomaticFocus(true)
        .create();

Developers create recognition result processing classes “FaceAnalyzerTransactor”, Implementation of this class MLAnalyzer.Result Interface , Use... In this class transactResult Methods to obtain the detection results of the face presented on the screen , And compare the width height ratio of the mobile phone screen with the width height ratio of the face presented on the screen , If the proportion of faces presented in front of the screen is too large , Then lock the screen

public class FaceAnalyzerTransactor implements MLAnalyzer.MLTransactor<MLFace> {
    @Override
    public void transactResult(MLAnalyzer.Result<MLFace> results) {
        SparseArray<MLFace> items = results.getAnalyseList();
        //  Developers process the identification results as needed , We need to pay attention to , Only the test results are processed here .
        //  Not callable ML kit Other detection related interfaces provided .

        if (items != null) {
            MLFace features = items.get(0);
            if (features == null) return;

            BigDecimal bigPhoneWidth = new BigDecimal(Float.toString(640));
            BigDecimal bigPhoneHeight = new BigDecimal(Float.toString(480));
            float phoneRatio = bigPhoneWidth.multiply(bigPhoneHeight).floatValue();

            BigDecimal bigFaceWidth = new BigDecimal(Float.toString(features.getWidth()));
            BigDecimal bigFaceHeight = new BigDecimal(Float.toString(features.getHeight()));
            float faceRatio = bigFaceWidth.multiply(bigFaceHeight).floatValue();

            BigDecimal bigPhoneRatio = new BigDecimal(Float.toString(phoneRatio));
            BigDecimal bigFaceRatio = new BigDecimal(Float.toString(faceRatio));
            final float ratio = bigPhoneRatio.divide(bigFaceRatio, 2, BigDecimal.ROUND_HALF_EVEN).floatValue();

            BigDecimal bigRatio = new BigDecimal(Float.toString(ratio));
            BigDecimal schedule = new BigDecimal(Float.toString(10));
            float scheduleRatio = bigRatio.multiply(schedule).floatValue();

            final int realRatio = Math.round(scheduleRatio);
            int distance = Integer.parseInt(mDistance);
            if (distance <= 6)
                distance = 6;

            if (distance >= realRatio) {
                //  Lock screen prompt , Too close to the screen , Screen lock screen 
            } else {
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        //  Prompt when approaching slowly , The distance from the screen 
                    }
                });
            }

        }
    }

    @Override
    public void destroy() {
        //  Detection end callback method , For releasing resources, etc .
        release();
    }
}

Set the recognition result processor , Implement the binding between analyzer and result processor

analyzer.setTransactor(new FaceAnalyzerTransactor());

call run Method , Start the camera , Read the video stream , For identification .

SurfaceView mSurfaceView = findViewById(R.id.surface_view);

try {
    lensEngine.run(mSurfaceView.getHolder());
} catch (IOException e) {
    //  exception handling 
    lensEngine.release();
    lensEngine = null;
}

Test complete , Stop the analyzer , Release detection resources

if (mLensEngine != null) {
    mLensEngine.release();
}
if (analyzer != null) {
    try {
        analyzer.stop();
    } catch (IOException e) {
        //  exception handling 
    }
}



maven Address 
buildscript {
    repositories {
        maven { url 'https://developer.huawei.com/repo/' }
    }
}
allprojects {
    repositories {
        maven { url 'https://developer.huawei.com/repo/' }
    }
}

Demo