def add_radiance(self, x, y, radiance):
        self[x, y, 0] += radiance[0]
        self[x, y, 1] += radiance[1]
        self[x, y, 2] += radiance[2]
add radiance (an RGB tuple) to given x, y position on image.
dataset/ETHPy150Open jtauber/pyifs/image.py/Image.add_radiance