执行doInBackground（）时发生错误，由OutOfMemory问题引起

Question

我是android开发的新手。我的应用程序是关于拍照和粘贴一些贴纸。我使用了一些开源过滤器代码。但我的应用程序经常崩溃，导致以下错误：

8971-9026/co.wansi.yixia E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #3
    Process: co.wansi.yixia, PID: 8971
    java.lang.RuntimeException: An error occured while executing doInBackground()
            at android.os.AsyncTask$3.done(AsyncTask.java:300)
            at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
            at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
            at java.util.concurrent.FutureTask.run(FutureTask.java:242)
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:841)
     Caused by: java.lang.OutOfMemoryError
            at co.wansi.yixia.ImageFilter.GaussianBlurFilter.ApplyBlur(GaussianBlurFilter.java:61)
            at co.wansi.yixia.ImageFilter.GaussianBlurFilter.process(GaussianBlurFilter.java:150)
            at co.wansi.yixia.ImageFilter.SoftGlowFilter.process(SoftGlowFilter.java:45)
            at co.wansi.yixia.yixia.act.picturedeal.view.PictureDetialFilterItemView$processImageTask.doInBackground(PictureDetialFilterItemView.java:108)
            at co.wansi.yixia.yixia.act.picturedeal.view.PictureDetialFilterItemView$processImageTask.doInBackground(PictureDetialFilterItemView.java:87)
            at android.os.AsyncTask$2.call(AsyncTask.java:288)
            at java.util.concurrent.FutureTask.run(FutureTask.java:237)
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:841)

我的代码是：

public class processImageTask extends AsyncTask<Void, Void, Bitmap> {
    private IImageFilter filter;
    private Activity activity = null;

    public processImageTask(Activity activity, IImageFilter imageFilter) {
        this.filter = imageFilter;
        this.activity = activity;
    }

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();
    }

    public Bitmap doInBackground(Void... params) {
        Image img = null;
        try {
            Bitmap bitmap = defaultBitmap;
            img = new Image(bitmap);
            if (filter != null) {
                img = filter.process(img);
                img.copyPixelsFromBuffer();
            }
            return img.getImage();
        } catch (Exception e) {
            if (img != null && img.destImage.isRecycled()) {
                img.destImage.recycle();
                img.destImage = null;
                System.gc(); 
            }
        } finally {
            if (img != null && img.image.isRecycled()) {
                img.image.recycle();
                img.image = null;
                System.gc();
            }
        }
        return null;
    }

    @Override
    protected void onPostExecute(Bitmap result) {
        if (result != null) {
            super.onPostExecute(result);
            mGPUImageView.setImageBitmap(result);
        }
    }
}

是out of memory还是multiple thread问题？