超简单集成HMS ML Kit 人脸检测实现可爱贴纸

前言

在这个美即真理、全民娱乐的时代，可爱有趣的人脸贴纸在各大美颜软件中得到了广泛的应用，现在已经不仅局限于相机美颜类软件中，在社交、娱乐类的app中对人脸贴纸、AR贴纸的需求也非常广泛。本文详细介绍了集成华为HMS ML kit人脸识别实现2d贴纸的集成过程，在后面的文章中我们还会介绍3D贴纸的开发过程，欢迎大家关注哦

场景

在美颜相机、美图app以及社交类app(如抖音、微博、微信)等需要对拍照，或者对照片进行处理的app都会构建自己特有的贴纸的需求。

开发前准备

在项目级gradle里添加华为maven仓

打开AndroidStudio项目级build.gradle文件

增量添加如下maven地址：

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

在应用级的build.gradle里面加上SDK依赖

// Face detection SDK.
implementation 'com.huawei.hms:ml-computer-vision-face:2.0.1.300'
// Face detection model.
implementation 'com.huawei.hms:ml-computer-vision-face-shape-point-model:2.0.1.300'

在AndroidManifest.xml文件里面申请相机、访问网络和存储权限

<!--相机权限--> 
<uses-feature android:name="android.hardware.camera" />
<uses-permission android:name="android.permission.CAMERA" />
<!--写权限--> 
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<!--读权限--> 
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

代码开发关键步骤

设置人脸检测器

MLFaceAnalyzerSetting detectorOptions;
detectorOptions = new MLFaceAnalyzerSetting.Factory()
        .setFeatureType(MLFaceAnalyzerSetting.TYPE_UNSUPPORT_FEATURES)
        .setShapeType(MLFaceAnalyzerSetting.TYPE_SHAPES)
        .allowTracing(MLFaceAnalyzerSetting.MODE_TRACING_FAST)
        .create();
detector = MLAnalyzerFactory.getInstance().getFaceAnalyzer(detectorOptions);

这里我们通过相机回调拿到相机帧数据,并通过调用人脸检测器拿到人脸轮廓点后写入FacePointEngine供贴纸滤镜使用.

@Override
public void onPreviewFrame(final byte[] imgData, final Camera camera) {
    int width = mPreviewWidth;
    int height = mPreviewHeight;

    long startTime = System.currentTimeMillis();
    //设置前后摄方向一致
    if (isFrontCamera()){
        mOrientation = 0;
    }else {
        mOrientation = 2;
    }
    MLFrame.Property property =
            new MLFrame.Property.Creator()
                    .setFormatType(ImageFormat.NV21)
                    .setWidth(width)
                    .setHeight(height)
                    .setQuadrant(mOrientation)
                    .create();

    ByteBuffer data = ByteBuffer.wrap(imgData);
    // 调用人脸检测接口
    SparseArray<MLFace> faces = detector.analyseFrame(MLFrame.fromByteBuffer(data,property));
    //判断是否获取到人脸信息
    if(faces.size()>0){
        MLFace mLFace = faces.get(0);
        EGLFace EGLFace = FacePointEngine.getInstance().getOneFace(0);
        EGLFace.pitch = mLFace.getRotationAngleX();
        EGLFace.yaw = mLFace.getRotationAngleY();
        EGLFace.roll = mLFace.getRotationAngleZ() - 90;
        if (isFrontCamera())
            EGLFace.roll = -EGLFace.roll;
        if (EGLFace.vertexPoints == null) {
            EGLFace.vertexPoints = new PointF[131];
        }
        int index = 0;
        // 获取一个人的轮廓点坐标并转化到openGL归一化坐标系下的浮点值
        for (MLFaceShape contour : mLFace.getFaceShapeList()) {
            if (contour == null) {
                continue;
            }
            List<MLPosition> points = contour.getPoints();

            for (int i = 0; i < points.size(); i++) {
                MLPosition point = points.get(i);
                float x = ( point.getY() / height) * 2 - 1;
                float y = ( point.getX() / width ) * 2 - 1;
                if (isFrontCamera())
                    x = -x;
                PointF Point = new PointF(x,y);
                EGLFace.vertexPoints[index] = Point;
                index++;
            }
        }
        // 插入人脸对象
        FacePointEngine.getInstance().putOneFace(0, EGLFace);
        // 设置人脸个数
        FacePointEngine.getInstance().setFaceSize(faces!= null ? faces.size() : 0);
    }else{
        FacePointEngine.getInstance().clearAll();
    }
    long endTime = System.currentTimeMillis();
    Log.d("TAG","Face detect time: " + String.valueOf(endTime - startTime));
}

ML kit接口返回的人脸轮廓点情况如图所示：

介绍如何设计贴纸,首先看一下贴纸数JSON数据定义

public class FaceStickerJson {

    public int[] centerIndexList;   // 中心坐标索引列表，有可能是多个关键点计算中心点
    public float offsetX;           // 相对于贴纸中心坐标的x轴偏移像素
    public float offsetY;           // 相对于贴纸中心坐标的y轴偏移像素
    public float baseScale;         // 贴纸基准缩放倍数
    public int startIndex;          // 人脸起始索引，用于计算人脸的宽度
    public int endIndex;            // 人脸结束索引，用于计算人脸的宽度
    public int width;               // 贴纸宽度
    public int height;              // 贴纸高度
    public int frames;              // 贴纸帧数
    public int action;              // 动作，0表示默认显示，这里用来处理贴纸动作等
    public String stickerName;      // 贴纸名称，用于标记贴纸所在文件夹以及png文件的
    public int duration;            // 贴纸帧显示间隔
    public boolean stickerLooping;  // 贴纸是否循环渲染
    public int maxCount;            // 最大贴纸渲染次数
	...
	}

我们制作猫耳贴纸JSON文件,通过人脸索引找到眉心84号点和鼻尖85号点分别贴上耳朵和鼻子,然后把它和图片都放在assets目录下

{
    "stickerList": [{
        "type": "sticker",
        "centerIndexList": [84],
        "offsetX": 0.0,
        "offsetY": 0.0,
        "baseScale": 1.3024,
        "startIndex": 11,
        "endIndex": 28,
        "width": 495,
        "height": 120,
        "frames": 2,
        "action": 0,
        "stickerName": "nose",
        "duration": 100,
        "stickerLooping": 1,
        "maxcount": 5
    }, {
        "type": "sticker",
        "centerIndexList": [83],
        "offsetX": 0.0,
        "offsetY": -1.1834,
        "baseScale": 1.3453,
        "startIndex": 11,
        "endIndex": 28,
        "width": 454,
        "height": 150,
        "frames": 2,
        "action": 0,
        "stickerName": "ear",
        "duration": 100,
        "stickerLooping": 1,
        "maxcount": 5
    }]
}

这里渲染贴纸纹理我们使用GLSurfaceView,使用起来比TextureView简单, 首先在onSurfaceChanged实例化贴纸滤镜,传入贴纸路径并开启相机

@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {

    GLES30.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    mTextures = new int[1];
    mTextures[0] = OpenGLUtils.createOESTexture();
    mSurfaceTexture = new SurfaceTexture(mTextures[0]);
    mSurfaceTexture.setOnFrameAvailableListener(this);

    //将samplerExternalOES 输入到纹理中
    cameraFilter = new CameraFilter(this.context);

    //设置assets目录下人脸贴纸路径
    String folderPath ="cat";
    stickerFilter = new FaceStickerFilter(this.context,folderPath);

    //创建屏幕滤镜对象
    screenFilter = new BaseFilter(this.context);

    facePointsFilter = new FacePointsFilter(this.context);
    mEGLCamera.openCamera();
}

然后在onSurfaceChanged初始化贴纸滤镜

@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
    Log.d(TAG, "onSurfaceChanged. width: " + width + ", height: " + height);
    int previewWidth = mEGLCamera.getPreviewWidth();
    int previewHeight = mEGLCamera.getPreviewHeight();
    if (width > height) {
        setAspectRatio(previewWidth, previewHeight);
    } else {
        setAspectRatio(previewHeight, previewWidth);
    }
    // 设置画面的大小,创建FrameBuffer,设置显示尺寸
    cameraFilter.onInputSizeChanged(previewWidth, previewHeight);
    cameraFilter.initFrameBuffer(previewWidth, previewHeight);
    cameraFilter.onDisplaySizeChanged(width, height);

    stickerFilter.onInputSizeChanged(previewHeight, previewWidth);
    stickerFilter.initFrameBuffer(previewHeight, previewWidth);
    stickerFilter.onDisplaySizeChanged(width, height);

    screenFilter.onInputSizeChanged(previewWidth, previewHeight);
    screenFilter.initFrameBuffer(previewWidth, previewHeight);
    screenFilter.onDisplaySizeChanged(width, height);

    facePointsFilter.onInputSizeChanged(previewHeight, previewWidth);
    facePointsFilter.onDisplaySizeChanged(width, height);
    mEGLCamera.startPreview(mSurfaceTexture);
}

最后通过onDrawFrame把贴纸绘制到屏幕

@Override
public void onDrawFrame(GL10 gl) {
    int textureId;
    // 清除屏幕和深度缓存
    GLES30.glClear(GLES30.GL_COLOR_BUFFER_BIT | GLES30.GL_DEPTH_BUFFER_BIT);
    //更新获取一张图
    mSurfaceTexture.updateTexImage();
    //获取SurfaceTexture转化矩阵
    mSurfaceTexture.getTransformMatrix(mMatrix);
    //设置相机显示转化矩阵
    cameraFilter.setTextureTransformMatrix(mMatrix);

    //绘制相机纹理
    textureId = cameraFilter.drawFrameBuffer(mTextures[0],mVertexBuffer,mTextureBuffer);
    //绘制贴纸纹理
    textureId = stickerFilter.drawFrameBuffer(textureId,mVertexBuffer,mTextureBuffer);
    //绘制到屏幕
    screenFilter.drawFrame(textureId , mDisplayVertexBuffer, mDisplayTextureBuffer);
    if(drawFacePoints){
        facePointsFilter.drawFrame(textureId, mDisplayVertexBuffer, mDisplayTextureBuffer);
    }
}

这样我们的贴纸就画到人脸上了.

Demo效果