diff --git a/y2023/constants/9971.json b/y2023/constants/9971.json
index 6d5cbf9..c7c467d 100644
--- a/y2023/constants/9971.json
+++ b/y2023/constants/9971.json
@@ -1,16 +1,16 @@
 {
   "cameras": [
     {
-      "calibration": {% include 'y2023/vision/calib_files/calibration_pi-971-4_cam-23-09_2013-01-18_09-02-59.650270322.json' %}
+      "calibration": {% include 'y2023/vision/calib_files/calibration_pi-9971-1_cam-23-09_ext_from971_2023-02-23.json' %}
     },
     {
-      "calibration": {% include 'y2023/vision/calib_files/calibration_pi-971-3_cam-23-10_2013-01-18_10-02-40.377380613.json' %}
+      "calibration": {% include 'y2023/vision/calib_files/calibration_pi-9971-2_cam-23-10_ext_from971_2023-02-23.json' %}
     },
     {
-      "calibration": {% include 'y2023/vision/calib_files/calibration_pi-971-2_cam-23-11_2013-01-18_10-01-30.177115986.json' %}
+      "calibration": {% include 'y2023/vision/calib_files/calibration_pi-9971-3_cam-23-11_ext_from971_2023-02-23.json' %}
     },
     {
-      "calibration": {% include 'y2023/vision/calib_files/calibration_pi-971-4_cam-23-08_2013-01-18_09-27-45.150551614.json' %}
+      "calibration": {% include 'y2023/vision/calib_files/calibration_pi-9971-4_cam-23-12_ext_from971_2023-02-23.json' %}
     }
   ],
   "target_map": {% include 'y2023/vision/maps/target_map.json' %}
diff --git a/y2023/vision/calib_files/calibration_pi-2023-base-calib.json b/y2023/vision/calib_files/calibration_pi-2023-base-calib.json
deleted file mode 100755
index d75e5ca..0000000
--- a/y2023/vision/calib_files/calibration_pi-2023-base-calib.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi1",
- "team_number": 7971,
- "intrinsics": [
-  893.759521,
-  0.0,
-  645.470764,
-  0.0,
-  893.222351,
-  388.150269,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.44902,
-  0.248409,
-  -0.000537,
-  -0.000112,
-  -0.076989
- ],
- "calibration_timestamp": 1358500519438113048,
- "camera_id": "23-00"
-}
diff --git a/y2023/vision/calib_files/calibration_pi-7971-1_cam-23-01_2013-01-18_09-15-19.438113048.json b/y2023/vision/calib_files/calibration_pi-7971-1_cam-23-01_2013-01-18_09-15-19.438113048.json
deleted file mode 100755
index c3ecd9e..0000000
--- a/y2023/vision/calib_files/calibration_pi-7971-1_cam-23-01_2013-01-18_09-15-19.438113048.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi1",
- "team_number": 7971,
- "intrinsics": [
-  893.759521,
-  0.0,
-  645.470764,
-  0.0,
-  893.222351,
-  388.150269,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.44902,
-  0.248409,
-  -0.000537,
-  -0.000112,
-  -0.076989
- ],
- "calibration_timestamp": 1358500519438113048,
- "camera_id": "23-01"
-}
diff --git a/y2023/vision/calib_files/calibration_pi-7971-2_cam-23-02_2013-01-18_09-02-49.498335208.json b/y2023/vision/calib_files/calibration_pi-7971-2_cam-23-02_2013-01-18_09-02-49.498335208.json
deleted file mode 100755
index 2e6f2a0..0000000
--- a/y2023/vision/calib_files/calibration_pi-7971-2_cam-23-02_2013-01-18_09-02-49.498335208.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi2",
- "team_number": 7971,
- "intrinsics": [
-  895.543945,
-  0.0,
-  645.250122,
-  0.0,
-  895.308838,
-  354.297241,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.455658,
-  0.272167,
-  0.000796,
-  -0.000206,
-  -0.0975
- ],
- "calibration_timestamp": 1358499769498335208,
- "camera_id": "23-02"
-}
\ No newline at end of file
diff --git a/y2023/vision/calib_files/calibration_pi-7971-3_cam-23-03_2013-01-18_09-39-27.378322133.json b/y2023/vision/calib_files/calibration_pi-7971-3_cam-23-03_2013-01-18_09-39-27.378322133.json
deleted file mode 100755
index d9c4154..0000000
--- a/y2023/vision/calib_files/calibration_pi-7971-3_cam-23-03_2013-01-18_09-39-27.378322133.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi3",
- "team_number": 7971,
- "intrinsics": [
-  892.089172,
-  0.0,
-  648.780701,
-  0.0,
-  892.362854,
-  342.340668,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.451178,
-  0.258187,
-  0.001071,
-  0.000017,
-  -0.085526
- ],
- "calibration_timestamp": 1358501967378322133,
- "camera_id": "23-03"
-}
\ No newline at end of file
diff --git a/y2023/vision/calib_files/calibration_pi-7971-4_cam-23-04_2013-01-18_09-39-42.039874176.json b/y2023/vision/calib_files/calibration_pi-7971-4_cam-23-04_2013-01-18_09-39-42.039874176.json
deleted file mode 100755
index aa541b5..0000000
--- a/y2023/vision/calib_files/calibration_pi-7971-4_cam-23-04_2013-01-18_09-39-42.039874176.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi4",
- "team_number": 7971,
- "intrinsics": [
-  890.071899,
-  0.0,
-  620.69519,
-  0.0,
-  890.307434,
-  365.158844,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.449088,
-  0.25594,
-  0.000415,
-  0.000142,
-  -0.084656
- ],
- "calibration_timestamp": 1358501982039874176,
- "camera_id": "23-04"
-}
\ No newline at end of file
diff --git a/y2023/vision/calib_files/calibration_pi-971-1_cam-23-01_2013-01-18_08-56-17.194305339.json b/y2023/vision/calib_files/calibration_pi-971-1_cam-23-01_2013-01-18_08-56-17.194305339.json
deleted file mode 100755
index c9d960a..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-1_cam-23-01_2013-01-18_08-56-17.194305339.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi1",
- "team_number": 971,
- "intrinsics": [
-  913.133728,
-  0.0,
-  575.592285,
-  0.0,
-  917.686462,
-  364.544403,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.454162,
-  0.255307,
-  -0.000166,
-  0.008949,
-  -0.079813
- ],
- "calibration_timestamp": 1358499377194305339,
- "camera_id": "23-01"
-}
diff --git a/y2023/vision/calib_files/calibration_pi-971-1_cam-23-05_2013-01-18_09-38-22.915096335.json b/y2023/vision/calib_files/calibration_pi-971-1_cam-23-05_2013-01-18_09-38-22.915096335.json
deleted file mode 100755
index 3afee2e..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-1_cam-23-05_2013-01-18_09-38-22.915096335.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi1",
- "team_number": 971,
- "intrinsics": [
-  890.980713,
-  0.0,
-  619.298645,
-  0.0,
-  890.668762,
-  364.009766,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.449172,
-  0.252318,
-  0.000881,
-  -0.000615,
-  -0.082208
- ],
- "calibration_timestamp": 1358501902915096335,
- "camera_id": "23-05"
-}
\ No newline at end of file
diff --git a/y2023/vision/calib_files/calibration_pi-971-1_cam-23-99_000000.json b/y2023/vision/calib_files/calibration_pi-971-1_cam-23-99_000000.json
deleted file mode 100644
index 4b41658..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-1_cam-23-99_000000.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi1",
- "team_number": 971,
- "intrinsics": [
-  893.759521,
-  0.0,
-  645.470764,
-  0.0,
-  893.222351,
-  388.150269,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.44902,
-  0.248409,
-  -0.000537,
-  -0.000112,
-  -0.076989
- ],
- "calibration_timestamp": 1358500519438113048,
- "camera_id": "23-99"
-}
diff --git a/y2023/vision/calib_files/calibration_pi-971-2_cam-23-06_2013-01-18_09-32-06.409252911.json b/y2023/vision/calib_files/calibration_pi-971-2_cam-23-06_2013-01-18_09-32-06.409252911.json
deleted file mode 100755
index 47f1d30..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-2_cam-23-06_2013-01-18_09-32-06.409252911.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi2",
- "team_number": 971,
- "intrinsics": [
-  893.242981,
-  0.0,
-  639.796692,
-  0.0,
-  892.498718,
-  354.109344,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.451751,
-  0.252422,
-  0.000531,
-  0.000079,
-  -0.079369
- ],
- "calibration_timestamp": 1358501526409252911,
- "camera_id": "23-06"
-}
\ No newline at end of file
diff --git a/y2023/vision/calib_files/calibration_pi-971-2_cam-23-11_2013-01-18_10-01-30.177115986.json b/y2023/vision/calib_files/calibration_pi-971-2_cam-23-11_2013-01-18_10-01-30.177115986.json
deleted file mode 100755
index 306bea1..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-2_cam-23-11_2013-01-18_10-01-30.177115986.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi3",
- "team_number": 971,
- "intrinsics": [
-  891.026001,
-  0.0,
-  620.086731,
-  0.0,
-  890.566895,
-  385.035126,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.448299,
-  0.250123,
-  -0.00042,
-  -0.000127,
-  -0.078433
- ],
- "calibration_timestamp": 1358503290177115986,
- "camera_id": "23-11"
-}
diff --git a/y2023/vision/calib_files/calibration_pi-971-2_cam-23-99_000000.json b/y2023/vision/calib_files/calibration_pi-971-2_cam-23-99_000000.json
deleted file mode 100644
index 9257aee..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-2_cam-23-99_000000.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi2",
- "team_number": 971,
- "intrinsics": [
-  893.759521,
-  0.0,
-  645.470764,
-  0.0,
-  893.222351,
-  388.150269,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.44902,
-  0.248409,
-  -0.000537,
-  -0.000112,
-  -0.076989
- ],
- "calibration_timestamp": 1358500519438113048,
- "camera_id": "23-99"
-}
diff --git a/y2023/vision/calib_files/calibration_pi-971-3_cam-23-07_2013-01-18_09-11-56.768663953.json b/y2023/vision/calib_files/calibration_pi-971-3_cam-23-07_2013-01-18_09-11-56.768663953.json
deleted file mode 100755
index fc78ef8..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-3_cam-23-07_2013-01-18_09-11-56.768663953.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi3",
- "team_number": 971,
- "intrinsics": [
-  892.627869,
-  0.0,
-  629.289978,
-  0.0,
-  891.73761,
-  373.299896,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.454901,
-  0.266778,
-  -0.000316,
-  -0.000469,
-  -0.091357
- ],
- "calibration_timestamp": 1358500316768663953,
- "camera_id": "23-07"
-}
diff --git a/y2023/vision/calib_files/calibration_pi-971-3_cam-23-10_2013-01-18_10-02-40.377380613.json b/y2023/vision/calib_files/calibration_pi-971-3_cam-23-10_2013-01-18_10-02-40.377380613.json
deleted file mode 100755
index 393beef..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-3_cam-23-10_2013-01-18_10-02-40.377380613.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi2",
- "team_number": 971,
- "intrinsics": [
-  894.002502,
-  0.0,
-  636.431335,
-  0.0,
-  893.723816,
-  377.069672,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.446659,
-  0.244189,
-  0.000632,
-  0.000171,
-  -0.074849
- ],
- "calibration_timestamp": 1358503360377380613,
- "camera_id": "23-10"
-}
diff --git a/y2023/vision/calib_files/calibration_pi-971-3_cam-23-99_000000.json b/y2023/vision/calib_files/calibration_pi-971-3_cam-23-99_000000.json
deleted file mode 100644
index 03b2687..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-3_cam-23-99_000000.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi3",
- "team_number": 971,
- "intrinsics": [
-  893.759521,
-  0.0,
-  645.470764,
-  0.0,
-  893.222351,
-  388.150269,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.44902,
-  0.248409,
-  -0.000537,
-  -0.000112,
-  -0.076989
- ],
- "calibration_timestamp": 1358500519438113048,
- "camera_id": "23-99"
-}
diff --git a/y2023/vision/calib_files/calibration_pi-971-4_cam-23-08_2013-01-18_09-27-45.150551614.json b/y2023/vision/calib_files/calibration_pi-971-4_cam-23-08_2013-01-18_09-27-45.150551614.json
deleted file mode 100755
index 5b92f75..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-4_cam-23-08_2013-01-18_09-27-45.150551614.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi4",
- "team_number": 971,
- "intrinsics": [
-  891.88385,
-  0.0,
-  642.268616,
-  0.0,
-  890.626465,
-  353.272919,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.448426,
-  0.246817,
-  0.000002,
-  0.000948,
-  -0.076717
- ],
- "calibration_timestamp": 1358501265150551614,
- "camera_id": "23-08"
-}
\ No newline at end of file
diff --git a/y2023/vision/calib_files/calibration_pi-971-4_cam-23-09_2013-01-18_09-02-59.650270322.json b/y2023/vision/calib_files/calibration_pi-971-4_cam-23-09_2013-01-18_09-02-59.650270322.json
deleted file mode 100755
index e119c43..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-4_cam-23-09_2013-01-18_09-02-59.650270322.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi1",
- "team_number": 971,
- "intrinsics": [
-  893.617798,
-  0.0,
-  612.44397,
-  0.0,
-  893.193115,
-  375.196381,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.443805,
-  0.238734,
-  0.000133,
-  0.000448,
-  -0.071068
- ],
- "calibration_timestamp": 1358499779650270322,
- "camera_id": "23-09"
-}
diff --git a/y2023/vision/calib_files/calibration_pi-971-4_cam-23-99_000000.json b/y2023/vision/calib_files/calibration_pi-971-4_cam-23-99_000000.json
deleted file mode 100644
index 4a0b632..0000000
--- a/y2023/vision/calib_files/calibration_pi-971-4_cam-23-99_000000.json
+++ /dev/null
@@ -1,24 +0,0 @@
-{
- "node_name": "pi4",
- "team_number": 971,
- "intrinsics": [
-  893.759521,
-  0.0,
-  645.470764,
-  0.0,
-  893.222351,
-  388.150269,
-  0.0,
-  0.0,
-  1.0
- ],
- "dist_coeffs": [
-  -0.44902,
-  0.248409,
-  -0.000537,
-  -0.000112,
-  -0.076989
- ],
- "calibration_timestamp": 1358500519438113048,
- "camera_id": "23-99"
-}
diff --git a/y2023/vision/calib_files/calibration_pi-9971-1_cam-23-09_ext_from971_2023-02-23.json b/y2023/vision/calib_files/calibration_pi-9971-1_cam-23-09_ext_from971_2023-02-23.json
new file mode 100644
index 0000000..b6e0def
--- /dev/null
+++ b/y2023/vision/calib_files/calibration_pi-9971-1_cam-23-09_ext_from971_2023-02-23.json
@@ -0,0 +1,25 @@
+{
+ "node_name": "pi1",
+ "team_number": 9971,
+ "intrinsics": [
+  893.617798,
+  0.0,
+  612.44397,
+  0.0,
+  893.193115,
+  375.196381,
+  0.0,
+  0.0,
+  1.0
+ ],
+ "dist_coeffs": [
+  -0.443805,
+  0.238734,
+  0.000133,
+  0.000448,
+  -0.071068
+ ],
+ "fixed_extrinsics": { "data": [ -0.487722, 0.222354, 0.844207, 0.025116, 0.864934, -0.008067, 0.501821, -0.246003, 0.118392, 0.974933, -0.188387, 0.532497, 0.0, 0.0, 0.0, 1.0 ] },
+ "calibration_timestamp": 1358499779650270322,
+ "camera_id": "23-09"
+}
diff --git a/y2023/vision/calib_files/calibration_pi-9971-2_cam-23-10_ext_from971_2023-02-23.json b/y2023/vision/calib_files/calibration_pi-9971-2_cam-23-10_ext_from971_2023-02-23.json
new file mode 100644
index 0000000..6293443
--- /dev/null
+++ b/y2023/vision/calib_files/calibration_pi-9971-2_cam-23-10_ext_from971_2023-02-23.json
@@ -0,0 +1,25 @@
+{
+ "node_name": "pi2",
+ "team_number": 9971,
+ "intrinsics": [
+  894.002502,
+  0.0,
+  636.431335,
+  0.0,
+  893.723816,
+  377.069672,
+  0.0,
+  0.0,
+  1.0
+ ],
+ "dist_coeffs": [
+  -0.446659,
+  0.244189,
+  0.000632,
+  0.000171,
+  -0.074849
+ ],
+ "fixed_extrinsics": { "data": [ 0.852213, 0.227336, 0.471224, 0.220072, 0.485092, -0.005909, -0.874443, -0.175232, -0.196008, 0.973799, -0.115315, 0.61409, 0.0, 0.0, 0.0, 1.0 ] },
+ "calibration_timestamp": 1358503360377380613,
+ "camera_id": "23-10"
+}
diff --git a/y2023/vision/calib_files/calibration_pi-9971-3_cam-23-11_ext_from971_2023-02-23.json b/y2023/vision/calib_files/calibration_pi-9971-3_cam-23-11_ext_from971_2023-02-23.json
new file mode 100644
index 0000000..ec4c69c
--- /dev/null
+++ b/y2023/vision/calib_files/calibration_pi-9971-3_cam-23-11_ext_from971_2023-02-23.json
@@ -0,0 +1,25 @@
+{
+ "node_name": "pi3",
+ "team_number": 9971,
+ "intrinsics": [
+  891.026001,
+  0.0,
+  620.086731,
+  0.0,
+  890.566895,
+  385.035126,
+  0.0,
+  0.0,
+  1.0
+ ],
+ "dist_coeffs": [
+  -0.448299,
+  0.250123,
+  -0.00042,
+  -0.000127,
+  -0.078433
+ ],
+ "fixed_extrinsics": { "data": [ 0.492232, -0.163335, -0.855002, 0.020122, -0.866067, 0.006706, -0.499883, -0.174518, 0.087382, 0.986548, -0.138158, 0.645307, 0.0, 0.0, 0.0, 1.0 ] },
+ "calibration_timestamp": 1358503290177115986,
+ "camera_id": "23-11"
+}
diff --git a/y2023/vision/calib_files/calibration_pi-9971-4_cam-23-12_ext_from971_2023-02-23.json b/y2023/vision/calib_files/calibration_pi-9971-4_cam-23-12_ext_from971_2023-02-23.json
new file mode 100644
index 0000000..3d0f566
--- /dev/null
+++ b/y2023/vision/calib_files/calibration_pi-9971-4_cam-23-12_ext_from971_2023-02-23.json
@@ -0,0 +1,25 @@
+{
+ "node_name": "pi4",
+ "team_number": 9971,
+ "intrinsics": [
+  891.127197,
+  0.0,
+  640.291321,
+  0.0,
+  891.176453,
+  359.578705,
+  0.0,
+  0.0,
+  1.0
+ ],
+ "dist_coeffs": [
+  -0.452948,
+  0.262567,
+  0.00088,
+  -0.000253,
+  -0.089368
+ ],
+ "fixed_extrinsics": { "data": [ -0.865915, -0.186983, -0.463928, -0.014873, -0.473362, 0.006652, 0.880843, -0.215738, -0.161617, 0.982341, -0.094271, 0.676433, 0.0, 0.0, 0.0, 1.0 ] },
+ "calibration_timestamp": 1358499579812698894,
+ "camera_id": "23-12"
+}
diff --git a/y2023/vision/calibrate_extrinsics.cc b/y2023/vision/calibrate_extrinsics.cc
index 10e1639..7e650a3 100644
--- a/y2023/vision/calibrate_extrinsics.cc
+++ b/y2023/vision/calibrate_extrinsics.cc
@@ -1,5 +1,6 @@
 #include "Eigen/Dense"
 #include "Eigen/Geometry"
+
 #include "absl/strings/str_format.h"
 #include "aos/events/logging/log_reader.h"
 #include "aos/events/logging/log_writer.h"
@@ -15,6 +16,8 @@
 #include "y2023/constants/constants_generated.h"
 #include "y2023/vision/vision_util.h"
 
+#include <opencv2/core/eigen.hpp>
+
 DEFINE_string(pi, "pi-7971-2", "Pi name to calibrate.");
 DEFINE_bool(plot, false, "Whether to plot the resulting data.");
 DEFINE_string(target_type, "charuco_diamond",
@@ -22,10 +25,12 @@
 DEFINE_string(image_channel, "/camera", "Channel to listen for images on");
 DEFINE_string(output_logs, "/tmp/calibration/",
               "Output folder for visualization logs.");
-DEFINE_string(base_intrinsics, "",
-              "Intrinsics to use for extrinsics calibration.");
+DEFINE_string(base_calibration, "",
+              "Intrinsics (and optionally extrinsics) to use for extrinsics "
+              "calibration.");
 DEFINE_string(output_calibration, "",
-              "Output json file to use for the resulting extrinsics.");
+              "Output json file to use for the resulting calibration "
+              "(intrinsics and extrinsics).");
 
 namespace frc971 {
 namespace vision {
@@ -51,7 +56,7 @@
       TargetType target_type = TargetTypeFromString(FLAGS_target_type);
       std::unique_ptr<aos::EventLoop> constants_event_loop =
           factory->MakeEventLoop("constants_fetcher", pi_event_loop->node());
-      if (FLAGS_base_intrinsics.empty()) {
+      if (FLAGS_base_calibration.empty()) {
         frc971::constants::ConstantsFetcher<y2023::Constants> constants_fetcher(
             constants_event_loop.get());
         *intrinsics =
@@ -60,7 +65,7 @@
                 pi_event_loop->node()->name()->string_view()));
       } else {
         *intrinsics = aos::JsonFileToFlatbuffer<calibration::CameraCalibration>(
-            FLAGS_base_intrinsics);
+            FLAGS_base_calibration);
       }
       extractor = std::make_unique<Calibration>(
           factory, pi_event_loop.get(), imu_event_loop.get(), FLAGS_pi,
@@ -75,7 +80,7 @@
   CHECK(pi_number);
   const std::string pi_name = absl::StrCat("pi", *pi_number);
 
-  aos::FlatbufferDetachedBuffer<calibration::CameraCalibration> intrinsics =
+  aos::FlatbufferDetachedBuffer<calibration::CameraCalibration> calibration =
       aos::FlatbufferDetachedBuffer<calibration::CameraCalibration>::Empty();
   {
     // Now, accumulate all the data into the data object.
@@ -102,7 +107,8 @@
     const aos::Node *const pi_node =
         aos::configuration::GetNode(factory.configuration(), pi_name);
 
-    CalibrationAccumulatorState accumulator_state(&factory, &data, &intrinsics);
+    CalibrationAccumulatorState accumulator_state(&factory, &data,
+                                                  &calibration);
 
     reader.OnStart(imu_node, [&accumulator_state, imu_node, &factory]() {
       accumulator_state.imu_event_loop =
@@ -152,6 +158,24 @@
   // Set y value to -1 m (approx distance from imu to the board/world)
   nominal_initial_state(1, 0) = 1.0;
 
+  // If available, pull extrinsics from the calibration file
+  const calibration::CameraCalibration *calib_msg = &calibration.message();
+  if (calib_msg->has_fixed_extrinsics()) {
+    LOG(INFO) << "Using extrinsiscs from calibration file as initial condition";
+    const cv::Mat extrinsics_cv(
+        4, 4, CV_32F,
+        const_cast<void *>(static_cast<const void *>(
+            calib_msg->fixed_extrinsics()->data()->data())));
+    CHECK_EQ(extrinsics_cv.total(),
+             calib_msg->fixed_extrinsics()->data()->size());
+    Eigen::Matrix4d ext_mat;
+    cv::cv2eigen(extrinsics_cv, ext_mat);
+    Eigen::Affine3d extrinsics(ext_mat);
+    Eigen::Affine3d H_camera_imu = extrinsics.inverse();
+    nominal_pivot_to_camera = H_camera_imu.rotation();
+    nominal_pivot_to_camera_translation = H_camera_imu.translation();
+  }
+
   CalibrationParameters calibration_parameters;
   calibration_parameters.initial_orientation = nominal_initial_orientation;
   calibration_parameters.pivot_to_camera = nominal_pivot_to_camera;
@@ -198,10 +222,10 @@
 
   aos::FlatbufferDetachedBuffer<calibration::CameraCalibration>
       solved_extrinsics = Solve(data, &calibration_parameters);
-  intrinsics.mutable_message()->clear_fixed_extrinsics();
-  intrinsics.mutable_message()->clear_turret_extrinsics();
+  calibration.mutable_message()->clear_fixed_extrinsics();
+  calibration.mutable_message()->clear_turret_extrinsics();
   aos::FlatbufferDetachedBuffer<calibration::CameraCalibration>
-      merged_calibration = aos::MergeFlatBuffers(&intrinsics.message(),
+      merged_calibration = aos::MergeFlatBuffers(&calibration.message(),
                                                  &solved_extrinsics.message());
 
   if (!FLAGS_output_calibration.empty()) {