diff --git a/ibl/evaluators.py b/ibl/evaluators.py
index a4e2ee5..f78f1c1 100644
--- a/ibl/evaluators.py
+++ b/ibl/evaluators.py
@@ -22,11 +22,15 @@
 def extract_cnn_feature(model, inputs, vlad=True, gpu=None):
     model.eval()
     inputs = to_torch(inputs).cuda(gpu)
-    x_pool, x_vlad = model(inputs)
-    if vlad:
-        outputs = F.normalize(x_vlad, p=2, dim=-1)
+    outputs = model(inputs)
+    if (isinstance(outputs, list) or isinstance(outputs, tuple)):
+        x_pool, x_vlad = outputs
+        if vlad:
+            outputs = F.normalize(x_vlad, p=2, dim=-1)
+        else:
+            outputs = F.normalize(x_pool, p=2, dim=-1)
     else:
-        outputs = F.normalize(x_pool, p=2, dim=-1)
+        outputs = F.normalize(outputs, p=2, dim=-1)
     return outputs
 
 def extract_features(model, data_loader, dataset, print_freq=10,
diff --git a/ibl/models/__init__.py b/ibl/models/__init__.py
index 7e41c43..40a0aab 100644
--- a/ibl/models/__init__.py
+++ b/ibl/models/__init__.py
@@ -8,6 +8,7 @@
     'vgg16': vgg16,
     'netvlad': NetVLAD,
     'embednet': EmbedNet,
+    'embednetpca': EmbedNetPCA,
     'embedregionnet': EmbedRegionNet,
 }
 
diff --git a/ibl/models/netvlad.py b/ibl/models/netvlad.py
index 483ec5d..9dff22c 100644
--- a/ibl/models/netvlad.py
+++ b/ibl/models/netvlad.py
@@ -81,6 +81,34 @@ def forward(self, x):
 
         return pool_x, vlad_x
 
+class EmbedNetPCA(nn.Module):
+    def __init__(self, base_model, net_vlad, dim=4096):
+        super(EmbedNetPCA, self).__init__()
+        self.base_model = base_model
+        self.net_vlad = net_vlad
+        self.pca_layer = nn.Conv2d(net_vlad.num_clusters*net_vlad.dim, dim, 1, stride=1, padding=0)
+
+    def _init_params(self):
+        self.base_model._init_params()
+        self.net_vlad._init_params()
+
+    def forward(self, x):
+        _, x = self.base_model(x)
+        vlad_x = self.net_vlad(x)
+
+        # [IMPORTANT] normalize
+        vlad_x = F.normalize(vlad_x, p=2, dim=2)  # intra-normalization
+        vlad_x = vlad_x.view(x.size(0), -1)  # flatten
+        vlad_x = F.normalize(vlad_x, p=2, dim=1)  # L2 normalize
+
+        # reduction
+        N, D = vlad_x.size()
+        vlad_x = vlad_x.view(N, D, 1, 1)
+        vlad_x = self.pca_layer(vlad_x).view(N, -1)
+        vlad_x = F.normalize(vlad_x, p=2, dim=-1)  # L2 normalize
+
+        return vlad_x
+
 class EmbedRegionNet(nn.Module):
     def __init__(self, base_model, net_vlad, tuple_size=1):
         super(EmbedRegionNet, self).__init__()
diff --git a/ibl/utils/osutils.py b/ibl/utils/osutils.py
index af3417d..9cb6f93 100644
--- a/ibl/utils/osutils.py
+++ b/ibl/utils/osutils.py
@@ -4,6 +4,7 @@
 
 
 def mkdir_if_missing(dir_path):
+    if not dir_path: return
     try:
         os.makedirs(dir_path)
     except OSError as e: