diff --git a/csst_ifs_sim/csst_ifs_sim.py b/csst_ifs_sim/csst_ifs_sim.py
index 82750afddebbf8f71a57d44643eaba8bcc559697..a6842cbb91d8e62450d2d3b24598169d44153ce4 100644
--- a/csst_ifs_sim/csst_ifs_sim.py
+++ b/csst_ifs_sim/csst_ifs_sim.py
@@ -2748,12 +2748,12 @@ class IFSsimulator():
         overscan = 320
         # zone 4 ,  OSH ####  1024,  2048
         self.image_b[0:1024+overscan, 0:2048+prescan+overscan] += np.random.normal(
-            loc=0.0, scale=self.information['rn2_b'], size=(1344, 2418))
+            loc=0.0, scale=self.information['rn1_b'], size=(1344, 2418))
 
         # ######### zone 3, OSG    #################
         np.random.seed()
         self.image_b[0:1024+overscan, 2418:2418+2048+prescan+overscan] += np.random.normal(
-            loc=0.0, scale=self.information['rn1_b'], size=(1344, 2418))
+            loc=0.0, scale=self.information['rn2_b'], size=(1344, 2418))
 
         # ######### zone 1, OSE  ###################
         np.random.seed()
@@ -2770,12 +2770,12 @@ class IFSsimulator():
         # red zone 4 , OSH### 1536* 3072
         np.random.seed()
         self.image_r[0:1536+overscan, 0:3072+prescan+overscan] += np.random.normal(
-            loc=0.0, scale=self.information['rn2_r'], size=(1856, 3442))
+            loc=0.0, scale=self.information['rn1_r'], size=(1856, 3442))
 
         # ######### zone 3 ,OSG #################
         np.random.seed()
         self.image_r[0:1536+overscan, 3442:3442+3072+prescan+overscan] += np.random.normal(
-            loc=0.0, scale=self.information['rn1_r'], size=(1856, 3442))
+            loc=0.0, scale=self.information['rn2_r'], size=(1856, 3442))
 
         # ######### zone 1 ,OSE ###################
         np.random.seed()
@@ -3024,10 +3024,10 @@ class IFSsimulator():
         ########################################################################
 
         # blue zone 4
-        self.image_b[0:1344, 0:2418] += self.information['bias2_b']
+        self.image_b[0:1344, 0:2418] += self.information['bias1_b']
 
         # ######### zone 3  #################
-        self.image_b[0:1344, 2418:2418*2] += self.information['bias1_b']
+        self.image_b[0:1344, 2418:2418*2] += self.information['bias2_b']
 
         # ######### zone 1  ###################
         self.image_b[0:1344, 2418*2:2418*3] += self.information['bias3_b']
@@ -3042,10 +3042,10 @@ class IFSsimulator():
         #######################################################################
 
         # red zone 4
-        self.image_r[0:1856, 0:3442] += self.information['bias2_r']
+        self.image_r[0:1856, 0:3442] += self.information['bias1_r']
 
         # ######### zone 3   #################
-        self.image_r[0:1856, 3442:3442*2] += self.information['bias1_r']
+        self.image_r[0:1856, 3442:3442*2] += self.information['bias2_r']
 
         # ######### zone 1  ###################
         self.image_r[0:1856, 3442*2:3442*3] += self.information['bias3_r']