[Feature] Add Cutout transform

mmseg/datasets/pipelines/transforms.py

@@ -977,7 +977,8 @@ def __init__(self,
                  n_holes,
                  cutout_shape=None,
                  cutout_ratio=None,
-                 fill_in=(0, 0, 0)):
+                 fill_in=(0, 0, 0),
+                 ignore_index=255):
 
         assert (cutout_shape is None) ^ (cutout_ratio is None), \
             'Either cutout_shape or cutout_ratio should be specified.'
@@ -989,6 +990,7 @@ def __init__(self,
             n_holes = (n_holes, n_holes)
         self.n_holes = n_holes
         self.fill_in = fill_in
+        self.ignore_index = ignore_index
         self.with_ratio = cutout_ratio is not None
         self.candidates = cutout_ratio if self.with_ratio else cutout_shape
         if not isinstance(self.candidates, list):
@@ -1012,6 +1014,9 @@ def __call__(self, results):
             y2 = np.clip(y1 + cutout_h, 0, h)
             results['img'][y1:y2, x1:x2, :] = self.fill_in
 
+            for key in results.get('seg_fields', []):
+                results[key][y1:y2, x1:x2] = self.ignore_index
+
         return results
 
     def __repr__(self):

tests/test_data/test_transform.py

@@ -530,7 +530,12 @@ def test_cutout():
     img = mmcv.imread(
         osp.join(osp.dirname(__file__), '../data/color.jpg'), 'color')
 
+    seg = np.array(
+        Image.open(osp.join(osp.dirname(__file__), '../data/seg.png')))
+
     results['img'] = img
+    results['gt_semantic_seg'] = seg
+    results['seg_fields'] = ['gt_semantic_seg']
     results['img_shape'] = img.shape
     results['ori_shape'] = img.shape
     results['pad_shape'] = img.shape
@@ -552,16 +557,20 @@ def test_cutout():
         type='CutOut',
         n_holes=(2, 4),
         cutout_shape=[(10, 10), (15, 15)],
-        fill_in=(255, 255, 255))
+        fill_in=(255, 255, 255),
+        ignore_index=255)
     cutout_module = build_from_cfg(transform, PIPELINES)
     cutout_result = cutout_module(copy.deepcopy(results))
     assert cutout_result['img'].sum() > img.sum()
+    assert cutout_result['gt_semantic_seg'].sum() > seg.sum()
 
     transform = dict(
         type='CutOut',
         n_holes=1,
         cutout_ratio=(0.8, 0.8),
-        fill_in=(255, 255, 255))
+        fill_in=(255, 255, 255),
+        ignore_index=255)
     cutout_module = build_from_cfg(transform, PIPELINES)
     cutout_result = cutout_module(copy.deepcopy(results))
     assert cutout_result['img'].sum() > img.sum()
+    assert cutout_result['gt_semantic_seg'].sum() > seg.sum()