set ce_enable in tuning_utils

src/openflexure_microscope_server/things/camera/picamera.py

@@ -826,6 +826,17 @@ class StreamingPiCamera2(BaseCamera):
             tf_utils.set_static_geq(self.tuning, offset)
             self._initialise_picamera()
 
+    @lt.thing_action
+    def set_ce_enable_to_off(self) -> None:
+        """Set the contrast enhancement to disabled.
+
+        Adaptive contrast enhancement modifies settings to adapt to each field
+        of view, causing inconsistent settings when capturing.
+        """
+        with self._streaming_picamera(pause_stream=True):
+            tf_utils.set_ce_to_disabled(self.tuning)
+            self._initialise_picamera()
+
     @lt.thing_action
     def full_auto_calibrate(self, portal: lt.deps.BlockingPortal) -> None:
         """Perform a full auto-calibration.
@@ -843,6 +854,7 @@ class StreamingPiCamera2(BaseCamera):
         self.flat_lens_shading()
         self.auto_expose_from_minimum()
         self.set_static_green_equalisation()
+        self.set_ce_enable_to_off()
         self.calibrate_lens_shading()
         self.reset_ccm()
         self.calibrate_white_balance()

src/openflexure_microscope_server/things/camera/picamera_tuning_file_utils.py

@@ -104,6 +104,26 @@ def geq_is_static(tuning: dict) -> bool:
     return geq["offset"] == 65535
 
 
+def set_ce_to_disabled(
+    tuning: dict,
+) -> None:
+    """Update the ``rpi.ce_enable`` section of a camera tuning dict.
+
+    :param tuning: the raspberry pi tuning file. This will be updated in-place to
+        set ce_enable to 0.
+    """
+    contrast = Picamera2.find_tuning_algo(tuning, "rpi.contrast")
+    contrast["ce_enable"] = (
+        0  # disable ce_enable to prevent adaptive contrast enhancement
+    )
+
+
+def ce_enable_is_static(tuning: dict) -> bool:
+    """Whether the ce_enable flag is disabled."""
+    contrast = Picamera2.find_tuning_algo(tuning, "rpi.contrast")
+    return contrast["ce_enable"] == 0
+
+
 def copy_alsc_section(from_tuning: dict, to_tuning: dict) -> None:
     """Copy the ``rpi.alsc`` algorithm from one tuning to another.