diff --git a/ClusterMap/clustermap.py b/ClusterMap/clustermap.py
index aa64dc3..abba914 100644
--- a/ClusterMap/clustermap.py
+++ b/ClusterMap/clustermap.py
@@ -84,7 +84,7 @@ def __init__(self, spots, gene_list, dapi=None, num_dims=3, xy_radius=None,z_rad
         self.cellcenter = None
     
     def preprocess(self,dapi_grid_interval=5, LOF=False, contamination=0.1, pct_filter=0.1):
-        preprocessing_data(self.spots, dapi_grid_interval, self.dapi_binary, LOF,contamination, self.xy_radius,pct_filter)
+        self.spots = preprocessing_data(self.spots, dapi_grid_interval, self.dapi_binary, LOF,contamination, self.xy_radius,pct_filter)
 
     def segmentation(self,cell_num_threshold=0.01, dapi_grid_interval=5, add_dapi=True,use_genedis=True):
         
@@ -796,4 +796,4 @@ def discover_subclusters(self, resol_gene, resol_niche, n_neighbors):
             ari = adjusted_rand_score(adata_g.obs['subclusters'], adata_n.obs['niche_subclusters'])
             print(f'Adjusted Rand index for cell type {ct} = {ari}')
             
-            ari_list.append(ari)
\ No newline at end of file
+            ari_list.append(ari)