Adaptively approximate the circle shape (wkentaro#945)

* daptively approximate the circle shape * Black Co-authored-by: Joshua <[email protected]> Co-authored-by: Kentaro Wada <[email protected]>
anmsajedulalam · Nov 11, 2021 · a792351 · a792351
1 parent f696ea7
commit a792351
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/examples/instance_segmentation/labelme2coco.py b/examples/instance_segmentation/labelme2coco.py
@@ -132,7 +132,9 @@ def main():
  if shape_type == "circle":
  (x1, y1), (x2, y2) = points
  r = np.linalg.norm([x2 - x1, y2 - y1])
- n_points_circle = 12
+ # r(1-cos(a/2))<x, a=2*pi/N => N>pi/arccos(1-x/r)
+ # x: tolerance of the gap between the arc and the line segment
+ n_points_circle = max(int(np.pi / np.arccos(1 - 1 / r)), 12)
  i = np.arange(n_points_circle)
  x = x1 + r * np.sin(2 * np.pi / n_points_circle * i)
  y = y1 + r * np.cos(2 * np.pi / n_points_circle * i)