#200 Expose more Helios parameters to config (3)

Use `target_pixel_brightness` from config

config/helios.config.default.json

@@ -5,6 +5,7 @@
   "min_seconds_between_state_changes": 180,
   "edge_pixel_threshold": 0.01,
   "edge_color_threshold": 40,
+  "target_pixel_brightness": 50,
   "save_images_to_archive": false,
   "save_current_image": false
 }

packages/core/threads/helios_thread.py

@@ -46,6 +46,7 @@ def __init__(
 
                 self.current_exposure: int = min(self.available_exposures)
                 self.last_autoexposure_time: float = 0.0
+                self.target_pixel_brightness: int = 0
                 self.available_exposures: list[int] = available_exposures
 
                 self.update_camera_settings(exposure=self.current_exposure)
@@ -141,7 +142,7 @@ def adjust_exposure(self) -> None:
         """This function will loop over all available exposures and
         take one image for each exposure. Then it sets exposure to
         the value where the overall mean pixel value color is closest
-        to 50.
+        to `self.target_pixel_brightness`.
 
         **For every exposure:**
 
@@ -200,8 +201,8 @@ class ExposureResult(pydantic.BaseModel):
         new_exposure = int(
             min(
                 exposure_results,
-                key=lambda r:
-                abs(sum(r.means) / _NUMBER_OF_EXPOSURE_IMAGES - 50),
+                key=lambda r: abs((sum(r.means) / _NUMBER_OF_EXPOSURE_IMAGES) -
+                                  self.target_pixel_brightness),
             ).exposure
         )
         self.update_camera_settings(exposure=new_exposure)
@@ -216,15 +217,28 @@ def run(
         self,
         station_id: str,
         edge_color_threshold: int,
+        target_pixel_brightness: int,
         save_images_to_archive: bool,
         save_current_image: bool,
     ) -> float:
         """Take an image and evaluate the sun conditions. Run autoexposure
         function every 5 minutes. Returns the edge fraction."""
+        perform_autoexposure: bool = False
         now = time.time()
         if (now - self.last_autoexposure_time) > 300:
-            self.adjust_exposure()
+            self.logger.debug("performing autoexposure after 5 minutes")
+            perform_autoexposure = True
+        if self.target_pixel_brightness != target_pixel_brightness:
+            self.logger.debug(
+                "performing autoexposure because target_pixel_brightness changed"
+                +
+                f" ({self.target_pixel_brightness} -> {target_pixel_brightness})"
+            )
+            perform_autoexposure = True
+        if perform_autoexposure:
+            self.target_pixel_brightness = target_pixel_brightness
             self.last_autoexposure_time = now
+            self.adjust_exposure()
 
         frame = self.take_image()
 
@@ -361,6 +375,8 @@ def main(headless: bool = False) -> None:
                     new_edge_fraction = helios_instance.run(
                         station_id=config.general.station_id,
                         edge_color_threshold=config.helios.edge_color_threshold,
+                        target_pixel_brightness=config.helios.
+                        target_pixel_brightness,
                         save_images_to_archive=(
                             config.helios.save_images_to_archive
                         ),

packages/core/types/config.py

@@ -205,6 +205,7 @@ class HeliosConfig(StricterBaseModel):
     min_seconds_between_state_changes: int = pydantic.Field(..., ge=0, le=3600)
     edge_pixel_threshold: float = pydantic.Field(..., ge=0, le=1)
     edge_color_threshold: int = pydantic.Field(..., ge=5, le=250)
+    target_pixel_brightness: int = pydantic.Field(..., ge=20, le=235)
     save_images_to_archive: bool
     save_current_image: bool
 
@@ -220,6 +221,7 @@ class PartialHeliosConfig(StricterBaseModel):
     )
     edge_pixel_threshold: Optional[float] = pydantic.Field(None, ge=0, le=1)
     edge_color_threshold: Optional[int] = pydantic.Field(None, ge=5, le=250)
+    target_pixel_brightness: Optional[int] = pydantic.Field(None, ge=20, le=235)
     save_images_to_archive: Optional[bool] = None
     save_current_image: Optional[bool] = None