opencv-图片转灰度

在opencv官网下载android sdk，导入并添加到项目中。

初始化opencv

private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
        @Override
        public void onManagerConnected(int status) {
            switch (status) {
                case SUCCESS:

                    break;
                default:
                    super.onManagerConnected(status);
                    break;
            }
        }
    };
 @Override
    protected void onResume() {
        super.onResume();
        if (!OpenCVLoader.initDebug()) {
            OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_0_0, this, mLoaderCallback);
        } else {
            mLoaderCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);
        }
    }

灰度化

    private Bitmap BGR2Gray(Bitmap bitmap) {
        Mat src = new Mat();
        Utils.bitmapToMat(bitmap,src);
        Mat dst = new Mat();
        Imgproc.cvtColor(src,dst,Imgproc.COLOR_BGR2GRAY);
        Utils.matToBitmap(dst,bitmap);
        return bitmap;
    }