From 22b1b8e83f1cb4e3a6a4113e3297fdb16dd47189 Mon Sep 17 00:00:00 2001
From: yuedong <fangyuedong@qxslab.cn>
Date: Mon, 4 Jul 2022 17:58:23 +0800
Subject: [PATCH] change the logical of adding Poisson noise in Chip.py
---
ObservationSim/Instrument/Chip/Chip.py | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/ObservationSim/Instrument/Chip/Chip.py b/ObservationSim/Instrument/Chip/Chip.py
index d54cbeb..1465f27 100755
--- a/ObservationSim/Instrument/Chip/Chip.py
+++ b/ObservationSim/Instrument/Chip/Chip.py
@@ -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
@@ -361,11 +374,11 @@ 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.)
- img.addNoise(poisson_noise)
+ # 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
if config["ins_effects"]["cosmic_ray"] == True and pointing_type=='MS':
--
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