@staticmethod
def ls8_sr_corr(img):
    """ Method to correct Landsat 8 based on Landsat 7 reflectance.
            This method scales the SR reflectance values to match LS7 reflectance
            The returned values are generally lower than input image
            based on roy et al 2016"""
    return img.select(['B2'], ['BLUE']).float().multiply(0.885).add(183).int16(
        ).addBands(img.select(['B3'], ['GREEN']).float().multiply(0.9317).
        add(123).int16()).addBands(img.select(['B4'], ['RED']).float().
        multiply(0.9372).add(123).int16()).addBands(img.select(['B5'], [
        'NIR']).float().multiply(0.8339).add(448).int16()).addBands(img.
        select(['B6'], ['SWIR1']).float().multiply(0.8639).add(306).int16()
        ).addBands(img.select(['B7'], ['SWIR2']).float().multiply(0.9165).
        add(116).int16()).addBands(img.select(['pixel_qa'], ['PIXEL_QA']).
        int16()).addBands(img.select(['radsat_qa'], ['RADSAT_QA']).int16()
        ).copyProperties(img).copyProperties(img, ['system:time_start',
        'system:time_end', 'system:index', 'system:footprint'])
