clarify optional properties

config/config.example.yml

@@ -64,9 +64,9 @@ cameras:
     ################
     # size: size of the region in pixels
     # x_offset/y_offset: position of the upper left corner of your region (top left of image is 0,0)
-    # min_person_area: minimum width*height of the bounding box for the detected person
-    # max_person_area: maximum width*height of the bounding box for the detected person
-    # threshold: The minimum decimal percentage (50% hit = 0.5) for the confidence from tensorflow
+    # min_person_area (optional): minimum width*height of the bounding box for the detected person
+    # max_person_area (optional): maximum width*height of the bounding box for the detected person
+    # threshold (optional): The minimum decimal percentage (50% hit = 0.5) for the confidence from tensorflow
     # Tips: All regions are resized to 300x300 before detection because the model is trained on that size.
     #       Resizing regions takes CPU power. Ideally, all regions should be as close to 300x300 as possible.
     #       Defining a region that goes outside the bounds of the image will result in errors.