def liftover(args):
    p = OptionParser(liftover.__doc__)
    p.add_option("--tilesize", default=50000, type="int",
                 help="The size for each tile [default: %default]")
    opts, args = p.parse_args(args)

    if len(args) != 1:
        sys.exit(not p.print_help())

    gffile, = args
    gff = Gff(gffile)
    for g in gff:
        seqid = g.seqid
        seqid, tilenum = seqid.rsplit(".", 1)
        tilenum = int(tilenum)
        g.seqid = seqid
        offset = tilenum * opts.tilesize
        g.start += offset
        g.end += offset
        print g
@return: a binary pv.Image representing the foreground pixels
dataset/ETHPy150Open tanghaibao/jcvi/formats/gff.py/liftover--crossover with--dataset/ETHPy150Open bolme/pyvision/src/pyvision/surveillance/MotionDetector.py/MotionDetector.getForegroundMask