diff --git a/model_server/base/roiset.py b/model_server/base/roiset.py
index a429b61fcbd3bf1ad43f05025a3fb651e92ec694..96162c95b6a069be79ab6771c63ed27d3ee52f00 100644
--- a/model_server/base/roiset.py
+++ b/model_server/base/roiset.py
@@ -580,17 +580,9 @@ class RoiSet(object):
             that return a single-channel PatchStack accessor of the same shape
         :return: None
         """
-
-        raw_acc = self.get_patches_acc(channels=channels, expanded=False, pad_to=None)  # all channels
-        if derived_channel_functions is not None:
-            mono_data = [raw_acc.get_mono(c).data for c in range(0, raw_acc.chroma)]
-            for fcn in derived_channel_functions:
-                der = fcn(raw_acc) # returns patch stack
-                if der.shape != mono_data[0].shape or der.dtype not in ['uint8', 'uint16']:
-                    raise DerivedChannelError(
-                        f'Error processing derived channel {der} with shape {der.shape_dict} and dtype {der.dtype}'
-                    )
-                self.accs_derived.append(der)
+        if self.count == 0:
+            self._df['classify_by_' + name] = None
+            return True
 
             # combine channels
             data_derived = [acc.data for acc in self.accs_derived]