diff --git a/april_vision/utils.py b/april_vision/utils.py
index bec9fa1..7bb227d 100644
--- a/april_vision/utils.py
+++ b/april_vision/utils.py
@@ -5,7 +5,6 @@
 from typing import Deque, NamedTuple, Optional, Tuple, Union
 
 import cv2
-import numpy as np
 from numpy.typing import NDArray
 
 from .marker import Marker, PixelCoordinates
@@ -30,7 +29,8 @@ def from_colour_frame(
         if colourspace is not None:
             grey_frame = cv2.cvtColor(colour_frame, colourspace)
         else:
-            grey_frame = colour_frame.copy()
+            # mypy doesn't understand that Mat is a numpy array
+            grey_frame = colour_frame.copy()  # type: ignore[assignment]
 
         return cls(
             grey_frame=grey_frame,
@@ -62,7 +62,7 @@ def annotate_text(
         cv2.putText(
             frame_type,
             text,
-            np.array(location, dtype=np.int32),
+            location,
             cv2.FONT_HERSHEY_DUPLEX,
             text_scale,
             color=text_colour,  # in BGR
diff --git a/april_vision/vision.py b/april_vision/vision.py
index 93d4b96..569e69f 100644
--- a/april_vision/vision.py
+++ b/april_vision/vision.py
@@ -122,7 +122,7 @@ def _annotate(
             for frame_type in frame:
                 cv2.polylines(
                     frame_type,
-                    [integer_corners],
+                    integer_corners.tolist(),
                     isClosed=True,
                     color=(0, 255, 0),  # Green (BGR)
                     thickness=line_thickness,
@@ -148,7 +148,7 @@ def _annotate(
 
                 cv2.polylines(
                     frame_type,
-                    [origin_square],
+                    origin_square.tolist(),
                     isClosed=True,
                     color=(0, 0, 255),  # red
                     thickness=line_thickness,
@@ -157,9 +157,10 @@ def _annotate(
                 marker_text_scale = text_scale * normalise_marker_text(marker)
 
                 # Approximately center the text
-                text_origin = np.array(marker.pixel_centre, dtype=np.int32)
-                text_origin += np.array(
-                    [-40 * marker_text_scale, 10 * marker_text_scale], dtype=np.int32)
+                text_origin = (
+                    int(marker.pixel_centre.x - 40 * marker_text_scale),
+                    int(marker.pixel_centre.y + 10 * marker_text_scale),
+                )
 
                 cv2.putText(
                     frame_type,