diff --git a/demo/mono_det_demo.py b/demo/mono_det_demo.py
index 42416fd9f4..6fa70d985a 100644
--- a/demo/mono_det_demo.py
+++ b/demo/mono_det_demo.py
@@ -57,7 +57,7 @@ def parse_args():
 
     call_args['inputs'] = dict(
         img=call_args.pop('img'), infos=call_args.pop('infos'))
-    call_args.pop('cam_type')
+    # call_args.pop('cam_type')
 
     if call_args['no_save_vis'] and call_args['no_save_pred']:
         call_args['out_dir'] = ''
diff --git a/mmdet3d/apis/inferencers/base_3d_inferencer.py b/mmdet3d/apis/inferencers/base_3d_inferencer.py
index 6564325e8c..173016fdff 100644
--- a/mmdet3d/apis/inferencers/base_3d_inferencer.py
+++ b/mmdet3d/apis/inferencers/base_3d_inferencer.py
@@ -167,7 +167,8 @@ def _dispatch_kwargs(self,
         kwargs['img_out_dir'] = out_dir
         kwargs['pred_out_dir'] = out_dir
         if cam_type != '':
-            kwargs['cam_type_dir'] = cam_type
+            kwargs['cam_type'] = cam_type
+            # kwargs['cam_type_dir'] = cam_type
         return super()._dispatch_kwargs(**kwargs)
 
     def __call__(self,
diff --git a/mmdet3d/apis/inferencers/mono_det3d_inferencer.py b/mmdet3d/apis/inferencers/mono_det3d_inferencer.py
index 22863ae166..82a23e52d0 100644
--- a/mmdet3d/apis/inferencers/mono_det3d_inferencer.py
+++ b/mmdet3d/apis/inferencers/mono_det3d_inferencer.py
@@ -117,6 +117,13 @@ def _inputs_to_list(self,
                 lidar2cam = np.asarray(
                     data_info['images'][cam_type]['lidar2cam'],
                     dtype=np.float32)
+
+                if cam2img.shape == (3, 3):
+                    cam2img_fixed = np.eye(4)
+                    cam2img_fixed[:3, :3] = cam2img
+                    cam2img = cam2img_fixed
+
+
                 if 'lidar2img' in data_info['images'][cam_type]:
                     lidar2img = np.asarray(
                         data_info['images'][cam_type]['lidar2img'],