From b56735ebae9491662c97fab376839814d1fb0a4b Mon Sep 17 00:00:00 2001
From: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>
Date: Fri, 6 Jan 2023 20:21:58 +0800
Subject: [PATCH] [Fix] _flip_keypoint of RandomFlip returns a wrong result
 (#2527)

---
 mmcv/transforms/processing.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/mmcv/transforms/processing.py b/mmcv/transforms/processing.py
index 09098f1990..96e1bb0a1c 100644
--- a/mmcv/transforms/processing.py
+++ b/mmcv/transforms/processing.py
@@ -1203,7 +1203,8 @@ def _flip_bbox(self, bboxes: np.ndarray, img_shape: Tuple[int, int],
             bboxes (numpy.ndarray): Bounding boxes, shape (..., 4*k)
             img_shape (tuple[int]): Image shape (height, width)
             direction (str): Flip direction. Options are 'horizontal',
-                'vertical'.
+                'vertical', and 'diagonal'.
+
         Returns:
             numpy.ndarray: Flipped bounding boxes.
         """
@@ -1239,7 +1240,8 @@ def _flip_keypoints(
             keypoints (numpy.ndarray): Keypoints, shape (..., 2)
             img_shape (tuple[int]): Image shape (height, width)
             direction (str): Flip direction. Options are 'horizontal',
-                'vertical'.
+                'vertical', and 'diagonal'.
+
         Returns:
             numpy.ndarray: Flipped keypoints.
         """
@@ -1259,7 +1261,7 @@ def _flip_keypoints(
             raise ValueError(
                 f"Flipping direction must be 'horizontal', 'vertical', \
                   or 'diagonal', but got '{direction}'")
-        flipped = np.concatenate([keypoints, meta_info], axis=-1)
+        flipped = np.concatenate([flipped, meta_info], axis=-1)
         return flipped
 
     def _flip_seg_map(self, seg_map: dict, direction: str) -> np.ndarray:
@@ -1357,6 +1359,7 @@ def transform(self, results: dict) -> dict:
 
         Args:
             results (dict): Result dict from loading pipeline.
+
         Returns:
             dict: Flipped results, 'img', 'gt_bboxes', 'gt_seg_map',
             'gt_keypoints', 'flip', and 'flip_direction' keys are