def translate_crops(crop_tuples, translate_tuple):
    """Translate crop tuples to be over the image are, i.e. left top at (0,0)."""
    crop_tuples_translated = []
    for crop_tuple in crop_tuples:
        crop_tuples_translated.append((crop_tuple[0] - translate_tuple[0], 
            crop_tuple[1] - translate_tuple[1], crop_tuple[2] -
            translate_tuple[0], crop_tuple[3] - translate_tuple[1]))
    return crop_tuples_translated
