with a glass of water

dodgeballtracker/metadata.py

@@ -1,14 +1,27 @@
+from typing import Optional
+
 from pydantic import BaseModel
+import numpy as np
+import cv2
+
 
 class KnownImagePoint(BaseModel):
-    height: float
     width: float
+    height: float
+
+    @classmethod
+    def from_vec(cls, vec: tuple[float, float]) -> 'KnownImagePoint':
+        return cls(width=vec[0], height=vec[1])
 
 
 class BirdViewPoint(BaseModel):
     x: float
     y: float
 
+    @classmethod
+    def from_vec(cls, vec: tuple[float, float]) -> 'BirdViewPoint':
+        return cls(x=vec[0], y=vec[1])
+
 
 class KnownPoint(BaseModel):
     image: KnownImagePoint
@@ -18,3 +31,14 @@ class KnownPoint(BaseModel):
 class VideoMetadata(BaseModel):
     knownPoints: list[KnownPoint]
 
+    def get_view_perspective_matrix(self) -> Optional[np.array]:
+        if len(self.knownPoints) < 4:
+            return None
+
+        empirical_source = np.float32(
+            [[k.image.width, k.image.height] for k in self.knownPoints])
+        empirical_target = np.float32(
+            [[k.bird_view.x, k.bird_view.y] for k in self.knownPoints])
+        pixel_per_meter = 100
+        return cv2.getPerspectiveTransform(empirical_source,
+                                           empirical_target * pixel_per_meter)