人脸识别趟坑历程

    private static final int TEN_DESIRED_ZOOM = 27;

      private void setZoom(Camera.Parameters parameters) {
        String zoomSupportedString = parameters.get("zoom-supported");
        if (zoomSupportedString != null && !Boolean.parseBoolean(zoomSupportedString)) {
            return;
        }

        int tenDesiredZoom = TEN_DESIRED_ZOOM;
        String maxZoomString = parameters.get("max-zoom");
        if (maxZoomString != null) {
            try {
                int tenMaxZoom = (int) (10.0 * Double.parseDouble(maxZoomString));
                if (tenDesiredZoom > tenMaxZoom) {
                    tenDesiredZoom = tenMaxZoom;
                }
            } catch (NumberFormatException nfe) {
                Log.e(TAG, "Bad max-zoom: " + maxZoomString);
            }
        }

        String takingPictureZoomMaxString = parameters.get("taking-picture-zoom-max");
        if (takingPictureZoomMaxString != null) {
            try {
                int tenMaxZoom = Integer.parseInt(takingPictureZoomMaxString);
                if (tenDesiredZoom > tenMaxZoom) {
                    tenDesiredZoom = tenMaxZoom;
                }
            } catch (NumberFormatException nfe) {
                Log.e(TAG, "Bad taking-picture-zoom-max: " + takingPictureZoomMaxString);
            }
        }

        String motZoomValuesString = parameters.get("mot-zoom-values");
        if (motZoomValuesString != null) {
            tenDesiredZoom = findBestMotZoomValue(motZoomValuesString, tenDesiredZoom);
        }

        String motZoomStepString = parameters.get("mot-zoom-step");
        if (motZoomStepString != null) {
            try {
                double motZoomStep = Double.parseDouble(motZoomStepString.trim());
                int tenZoomStep = (int) (10.0 * motZoomStep);
                if (tenZoomStep > 1) {
                    tenDesiredZoom -= tenDesiredZoom % tenZoomStep;
                }
            } catch (NumberFormatException nfe) {
                // continue
            }
        }

        if (parameters.isZoomSupported()) {
            Log.e(TAG, "max-zoom:" + parameters.getMaxZoom());
            if (SystemUtils.isMadGlass() && parameters.getMaxZoom() >= 8) {
                parameters.setZoom(8);
            } else {
                parameters.setZoom(parameters.getMaxZoom() / tenDesiredZoom);
            }
        } else {
            Log.e(TAG, "Unsupported zoom.");
        }

        // Most devices, like the Hero, appear to expose this zoom parameter.
        // It takes on values like "27" which appears to mean 2.7x zoom
        // if (takingPictureZoomMaxString != null) {
        // parameters.set("taking-picture-zoom", tenDesiredZoom);
        // }
    }

  private void decode(final byte[] data, int width, int height) {
        YuvImage yuv = new YuvImage(data, ImageFormat.NV21, width, height, null);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        yuv.compressToJpeg(new Rect(0, 0, width, height), 100, out);

        byte[] bytes = out.toByteArray();
        final Bitmap picture = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
      ......

     private static final int MAX_FACE_NUM = 4;//最大可以检测出的人脸数量
    
    public void faceDetect(Bitmap srcImg) {
        Bitmap bm = srcImg.copy(Bitmap.Config.RGB_565, true);
        //最关键的就是下面三句代码
        FaceDetector faceDetector = new FaceDetector(bm.getWidth(), bm.getHeight(), MAX_FACE_NUM);
        FaceDetector.Face[] faces = new FaceDetector.Face[MAX_FACE_NUM];
        int realFaceNum = faceDetector.findFaces(bm, faces);
        Log.i(tag, "检测到人脸：n = " + realFaceNum);
        for (int i = 0; i < realFaceNum; i++) {
            FaceDetector.Face f = faces[i];
            PointF midPoint = new PointF();
            float dis = f.eyesDistance();//获取人脸两眼的间距
            f.getMidPoint(midPoint); //获取人脸中心点
            int dd = (int) (dis);
            Point eyeLeft = new Point((int) (midPoint.x - dis / 2), (int) midPoint.y);
            Point eyeRight = new Point((int) (midPoint.x + dis / 2), (int) midPoint.y);
            Rect faceRect = new Rect((int) (midPoint.x - dd), (int) (midPoint.y - dd), (int) (midPoint.x + dd), (int) (midPoint.y + dd));
            Log.i(tag, "左眼坐标 x = " + eyeLeft.x + "y = " + eyeLeft.y);
            Canvas canvas = new Canvas(bm);
            Paint p = new Paint();
            p.setAntiAlias(true);
            p.setStrokeWidth(8);
            p.setStyle(Paint.Style.STROKE);
            p.setColor(Color.GREEN);
            canvas.drawCircle(eyeLeft.x, eyeLeft.y, 20, p);
            canvas.drawCircle(eyeRight.x, eyeRight.y, 20, p);
            canvas.drawRect(faceRect, p);
        }
        ImageUtil.saveJpeg(bm);
        Log.i(tag, "保存完毕");
    }