使面部检测器适用于任何文件格式

Question

由于面部检测器仅适用于jpg文件,如何使其适用于所有格式？我让用户从SD卡中选择任何图像,因此图像可以是任何格式.比我在本文中提到的使用decodefile方法缩小图像: Android:将大型位图文件调整为缩放输出文件

我的问题是:
我们可以在decodefile方法中添加一些方法来首先将图像转换为jpg吗？
将图像转换为jpg的最佳和最有效的方法是什么,以便面部检测器类检测面部？

我的代码到目前为止:

public FaceView(Context context) {
            super(context);                         
            File photo = new File(selectedImagePath);                       
            sourceImage = decodeFile(photo);

            picWidth = sourceImage.getWidth();
            picHeight = sourceImage.getHeight(); 

            sourceImage = Bitmap.createScaledBitmap (sourceImage, picWidth, picHeight, false);                                      

            arrayFaces = new FaceDetector( picWidth, picHeight, NUM_FACES );
            arrayFaces.findFaces(sourceImage, getAllFaces);

            for (int i = 0; i < getAllFaces.length; i++)
            {
                getFace = getAllFaces[i];
                try {
                    PointF eyesMP = new PointF();
                    getFace.getMidPoint(eyesMP);
                    eyesDistance[i] = getFace.eyesDistance();
                    Log.d("1st eye distance", "" + getFace.eyesDistance());
                    eyesMidPts[i] = eyesMP;                 
                }
                catch (Exception e)
                {
                    if (DEBUG) Log.e("Face", i + " is null");
                }
            }                   
        }

解码方法:

private Bitmap decodeFile(File f){
            Bitmap b = null;
            int screenWidth = 0;
            int screenHeight = 0;
            Point size = new Point();
            WindowManager w = getWindowManager();

            if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2)
            {
                w.getDefaultDisplay().getSize(size);
                screenWidth = size.x;
                screenHeight = size.y; 
            }
            else
            {
                Display d = w.getDefaultDisplay(); 
                screenWidth = d.getWidth(); 
                screenHeight = d.getHeight(); 
            }

            //Decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();      
            o.inJustDecodeBounds = true;

            FileInputStream fis = null;
            try{
                fis = new FileInputStream(f);
                BitmapFactory.decodeStream(fis, null, o);
                fis.close();

                // was > IMAGE_MAX_SIZE for both i changed it****
                int scale = 1;
                if (o.outHeight > screenHeight || o.outWidth > screenWidth) {
                    scale = (int)Math.pow(2, (int) Math.round(Math.log(screenHeight / 
                            (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));
                }

                //Decode with inSampleSize
                BitmapFactory.Options o2 = new BitmapFactory.Options();
                o2.inSampleSize = scale;
                fis = new FileInputStream(f);
                b = BitmapFactory.decodeStream(fis, null, o2);
                fis.close();        
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
            return b;
        }

Answer 1

在decodeFile()方法结束时,您有一个位图.您可以轻松地依赖Android的将其转换成一个JPEG使用

Bitmap.compress(Bitmap.CompressFormat format, int quality, OutputStream stream)

同 Bitmap.CompressFormat.JPEG

这里有更多信息:在android中将位图转换为jpeg

您应该能够将其保存到文件中,或将其压缩到内存中(可能使用ByteArrayOutputStream？)