adds anchor grid

mmp/a4/label_grid.py

@@ -5,10 +5,34 @@ from ..a3.annotation import AnnotationRect
 
 
 def iou(rect1: AnnotationRect, rect2: AnnotationRect) -> float:
-    raise NotImplementedError()
+    x_left = max(rect1.x1, rect2.x1)
+    y_top = max(rect1.y1, rect2.y1)
+    x_right = min(rect1.x2, rect2.x2)
+    y_bottom = min(rect1.y2, rect2.y2)
+
+    # Returns 0 if no overlap
+    if x_right <= x_left or y_bottom <= y_top:
+        return 0.0
+
+    intersection_area = (x_right - x_left) * (y_bottom - y_top)
+
+    rect1_area = rect1.area()
+    rect2_area = rect2.area()
+
+    union_area = rect1_area + rect2_area - intersection_area
+
+    return intersection_area / union_area
 
 
 def get_label_grid(
     anchor_grid: np.ndarray, gts: Sequence[AnnotationRect], min_iou: float
 ) -> tuple[np.ndarray, ...]:
-    raise NotImplementedError()
+    label_grid = np.empty(anchor_grid.shape[:-1], dtype=bool)
+    for (width, ratio, row, col), item in np.ndenumerate(anchor_grid):
+        for gt in gts:
+            iou = iou(item, gt)
+            label_grid[width, ratio, row, col] = False
+            if (iou >= min_iou):
+                label_grid[width, ratio, row, col] = True
+                break
+    return label_grid