Android align image in top and center in RelativeLayout

I'm trying to align image to top of my Relative Layout and after that center it horizontally. Here is the code I'm using for :

<ImageView  
        android:id="@+id/collection_image_background"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"  />

,but this code is not working. My image is centered,but not aligned at top of my Relative Layout. I tried with android:scaleType="fitStart", but it's actually align imag left and top of it's parent.

So any idea how I can align the image correctly as I need?

P.S. I forget to mention that I'm setting the image to my ImageView like this :

    BitmapFactory.Options o2 = new BitmapFactory.Options();
    o2.inTempStorage = new byte[8*1024];

    ops = BitmapFactory.decodeStream(cis,null,o2);
    ImageView view = (ImageView) findViewById(R.id.collection_image_background);
    view.setImageBitmap(ops);