def osavi(b4, b8):
    """
    Optimized Soil-Adjusted Vegetation Index \
    (Rondeaux, Steven, and Baret, 1996).

    .. math:: OSAVI = 1.16 * b8 - (b4 / b8) + b4 + 0.16

    :param b4: Red.
    :type b4: numpy.ndarray or float
    :param b8: NIR.
    :type b8: numpy.ndarray or float

    :returns OSAVI: Index value

    .. Tip::

        Rondeaux, G., Steven, M., Baret, F. 1996. \
        Optimization of soil-adjusted vegetation indices. \
        Remote Sensing of Environment 55, 95-107. \
        doi:10.1016/0034-4257(95)00186-7.
    """

    OSAVI = 1.16 * b8 - (b4 / b8) + b4 + 0.16
    return OSAVI