[Fix] Fix inferencer (#3333)

mmseg/apis/mmseg_inferencer.py

@@ -59,7 +59,9 @@ class MMSegInferencer(BaseInferencer):
 
     preprocess_kwargs: set = set()
     forward_kwargs: set = {'mode', 'out_dir'}
-    visualize_kwargs: set = {'show', 'wait_time', 'img_out_dir', 'opacity'}
+    visualize_kwargs: set = {
+        'show', 'wait_time', 'img_out_dir', 'opacity', 'return_vis'
+    }
     postprocess_kwargs: set = {'pred_out_dir', 'return_datasample'}
 
     def __init__(self,
@@ -137,6 +139,7 @@ def __call__(self,
                  inputs: InputsType,
                  return_datasamples: bool = False,
                  batch_size: int = 1,
+                 return_vis: bool = False,
                  show: bool = False,
                  wait_time: int = 0,
                  out_dir: str = '',
@@ -188,11 +191,13 @@ def __call__(self,
             wait_time=wait_time,
             img_out_dir=img_out_dir,
             pred_out_dir=pred_out_dir,
+            return_vis=return_vis,
             **kwargs)
 
     def visualize(self,
                   inputs: list,
                   preds: List[dict],
+                  return_vis: bool = False,
                   show: bool = False,
                   wait_time: int = 0,
                   img_out_dir: str = '',
@@ -213,12 +218,12 @@ def visualize(self,
         Returns:
             List[np.ndarray]: Visualization results.
         """
-        if self.visualizer is None or (not show and img_out_dir == ''):
+        if not show and img_out_dir == '' and not return_vis:
             return None
-
-        if getattr(self, 'visualizer') is None:
+        if self.visualizer is None:
             raise ValueError('Visualization needs the "visualizer" term'
-                             'defined in the config, but got None')
+                             'defined in the config, but got None.')
+
         self.visualizer.set_dataset_meta(**self.model.dataset_meta)
         self.visualizer.alpha = opacity
 
@@ -250,10 +255,11 @@ def visualize(self,
                 draw_gt=False,
                 draw_pred=True,
                 out_file=out_file)
-            results.append(self.visualizer.get_image())
+            if return_vis:
+                results.append(self.visualizer.get_image())
             self.num_visualized_imgs += 1
 
-        return results
+        return results if return_vis else None
 
     def postprocess(self,
                     preds: PredType,