perf: optimize rectangle detection algorithm

- Check only first child contour instead of iterating all siblings
- Add area threshold check on inner contour
- Require inner contour to be rectangular with no deeper nesting

workspace/src/algorithm_pkg/algorithm_pkg/vision_node.py

@@ -160,25 +160,29 @@ class VisionNode(Node):
         best_inner_idx = -1
         for i, cnt in enumerate(contours):
             area = cv2.contourArea(cnt)
+            # 筛选：面积必须大于阈值
             if area < THRESHOLD_AREA:
                 continue
-            if not _is_rect(cnt):
+            # 筛选：外轮廓必须是矩形
-                continue
-            # Require an inner rectangular child contour
-            child_idx = hierarchy[0][i][2]
-            has_inner_rect = False
-            while child_idx != -1:
-                if _is_rect(contours[child_idx]) and hierarchy[0][child_idx][2] == -1:
-                    has_inner_rect = True
-                    break
-                child_idx = hierarchy[0][child_idx][0]  # next sibling
-            if not has_inner_rect:
-                continue
             approx = cv2.approxPolyDP(cnt, 0.02 * cv2.arcLength(cnt, True), True)
-            if area > best_area:
+            if not (len(approx) == 4 and cv2.isContourConvex(approx)):
-                best_area = area
+                continue
-                best = approx.reshape(4, 2)
+            # 筛选：必须有子轮廓
-                best_inner_idx = child_idx
+            # 取第一个子轮廓的索引
+            child_idx = hierarchy[0][i][2]
+            # 这个子轮廓需要满足以下要求:
+            # 1.无平行轮廓（兄弟轮廓）;
+            # 2.内轮廓不能有子轮廓;
+            # 3.内轮廓必须满足面积要求;
+            # 4.内轮廓必须是矩形;
+            if  hierarchy[0][child_idx][0] == -1\
+            and hierarchy[0][child_idx][2] == -1\
+            and cv2.contourArea(contours[child_idx]) > THRESHOLD_AREA\
+            and _is_rect(contours[child_idx]):
+                if area > best_area:
+                    best_area = area
+                    best = approx.reshape(4, 2)
+                    best_inner_idx = child_idx
 
         # Draw all contours on closed for debugging
         vis = cv2.cvtColor(closed, cv2.COLOR_GRAY2BGR)