def estimate_noise(self, image):
"""
:param image: noisy data, background subtracted
:return: estimated noise map sqrt(variance) for each pixel as estimated from the instrument and observation
"""
return np.sqrt(self.background_noise**2 + data_util.flux_noise(image, self.exposure_time)**2)
def test_flux_noise():
noise = data_util.flux_noise(cps_pixel=10, exposure_time=100)
npt.assert_almost_equal(noise, 1, decimal=5)