Commit 22b1b8e8 authored by Fang Yuedong's avatar Fang Yuedong
Browse files

change the logical of adding Poisson noise in Chip.py

parent da9c9fbe

ObservationSim/Instrument/Chip/Chip.py

+18 −5
Original line number Diff line number Diff line
@@ -316,9 +316,22 @@ class Chip(FocalPlane): 
            BoolDeadPix = False

        self.logger = logger



        # Get Poisson noise generator

        seed = int(config["random_seeds"]["seed_poisson"]) + pointing_ID*30 + self.chipID

        rng_poisson = galsim.BaseDeviate(seed)

        poisson_noise = galsim.PoissonNoise(rng_poisson, sky_level=0.)



        # Add sky background

        if sky_map is None:

            sky_map = filt.getSkyNoise(exptime=self.exptime)

            sky_map = sky_map * np.ones_like(img.array)

            sky_map = galsim.Image(array=sky_map)

            # Apply Poisson noise to the sky map

            # (NOTE): only for photometric chips

            # since it utilize the photon shooting

            # to draw stamps

            if self.survey_type == "photometric":

                sky_map.addNoise(poisson_noise)

        elif img.array.shape != sky_map.shape:

            raise ValueError("The shape img and sky_map must be equal.")

        elif tel is not None: # If sky_map is given in flux
@@ -361,10 +374,10 @@ class Chip(FocalPlane): 
                del shutt_gsimg

            del shuttimg



        # Add Poisson noise

        seed = int(config["random_seeds"]["seed_poisson"]) + pointing_ID*30 + self.chipID

        rng_poisson = galsim.BaseDeviate(seed)

        poisson_noise = galsim.PoissonNoise(rng_poisson, sky_level=0.)

        # Add Poisson noise to the resulting images

        # (NOTE): this can only applied to the slitless image

        # since it dose not use photon shooting to draw stamps

        if self.survey_type == "spectroscopic":

            img.addNoise(poisson_noise)



        # Add cosmic-rays