add support for resizing multiple sem segs (open-mmlab#5747)

mmdet/datasets/pipelines/transforms.py

@@ -270,7 +270,7 @@ def _resize_seg(self, results):
                     results['scale'],
                     interpolation='nearest',
                     backend=self.backend)
-            results['gt_semantic_seg'] = gt_seg
+            results[key] = gt_seg
 
     def __call__(self, results):
         """Call function to resize images, bounding boxes, masks, semantic

tests/test_data/test_pipelines/test_transform/test_transform.py

@@ -81,6 +81,28 @@ def test_resize():
     assert results['img_shape'] == (800, 1280, 3)
     assert results['img'].dtype == results['img'].dtype == np.uint8
 
+    results_seg = {
+        'img': img,
+        'img_shape': img.shape,
+        'ori_shape': img.shape,
+        'gt_semantic_seg': copy.deepcopy(img),
+        'gt_seg': copy.deepcopy(img),
+        'seg_fields': ['gt_semantic_seg', 'gt_seg']
+    }
+    transform = dict(
+        type='Resize',
+        img_scale=(640, 400),
+        multiscale_mode='value',
+        keep_ratio=False)
+    resize_module = build_from_cfg(transform, PIPELINES)
+    results_seg = resize_module(results_seg)
+    assert results_seg['gt_semantic_seg'].shape == results_seg['gt_seg'].shape
+    assert results_seg['img_shape'] == (400, 640, 3)
+    assert results_seg['img_shape'] != results_seg['ori_shape']
+    assert results_seg['gt_semantic_seg'].shape == results_seg['img_shape']
+    assert np.equal(results_seg['gt_semantic_seg'],
+                    results_seg['gt_seg']).all()
+
 
 def test_flip():
     # test assertion for invalid flip_ratio