def parameter_projection(parameters):
    """Projection of the parameters from level l to level l+1.

    Citing the paper: `The projection of the motion parameters from one level onto the next one consists merely of multiplying a0 and a1 by 2, and dividing a6 and a7 by two.`

    Args:
        parameters (list): the list of the current parameters for motion model at level l.

    Returns:
        parameters (list): the list of the updated parameters for motion model at level l+1.
    """
    # scale transition parameters
    # a0
    parameters[0] = parameters[0] * 2
    # b0
    parameters[3] = parameters[3] * 2
    return parameters