def METHOD_NAME(self, img, metadata):
    # The absolute radiometric correction follows this equation
    # L = GAIN * DN * abscalfactor / effective bandwidth + OFFSET
    # absCalFactor and effective Bandwidth are in the image metafile (IMD)
    GAIN = [0.905, 0.940, 0.938, 0.962, 0.964, 1.0, 0.961, 0.978,
            1.20, 1.227, 1.199, 1.196, 1.262, 1.314, 1.346, 1.376]
    OFFSET = [-8.604, -5.809, -4.996, -3.646, -3.021, -4.521, -5.522,
              -2.992, -5.546, -2.6, -2.309, -1.676, -0.705, -0.669,
              -0.512, -0.372]
    absCalFactor = metadata['absCalFactor']
    effectiveBandwidth = metadata['effectiveBandwidth']
    corrected_img = img.copy()
    for i in range(img.shape[2]):
        corrected_img[:, :, i] = GAIN[i] * img[:, :, i] * \
            (float(absCalFactor[i]) /
             float(effectiveBandwidth[i])) + OFFSET[i]
    return corrected_img