diff --git a/mini-nav/feature_retrieval.py b/mini-nav/feature_retrieval.py
index df4ab32..cb12b60 100644
--- a/mini-nav/feature_retrieval.py
+++ b/mini-nav/feature_retrieval.py
@@ -1,8 +1,10 @@
-from typing import Any, Dict, List, Optional, cast
+from typing import Any, Dict, List, Optional, Union, cast
 
+import polars as pl
 import torch
 from database import db_manager
-from datasets import Dataset, load_dataset
+from datasets import load_dataset
+from PIL import Image
 from tqdm.auto import tqdm
 from transformers import AutoImageProcessor, AutoModel
 
@@ -101,10 +103,37 @@ class FeatureRetrieval:
                 ]
             )
 
+    @torch.no_grad()
+    def extract_single_image_feature(self, image: Union[Image.Image, Any]) -> pl.Series:
+        """Extract feature from a single image without storing to database.
+
+        Args:
+            image: A single image (PIL Image or other supported format).
+
+        Returns:
+            pl.Series: The extracted CLS token feature vector as a Polars Series.
+        """
+        device = self.model.device
+        self.model.eval()
+
+        # 预处理图片
+        inputs = self.processor(images=image, return_tensors="pt")
+        inputs.to(device, non_blocking=True)
+
+        # 提取特征
+        outputs = self.model(**inputs)
+
+        # 获取 CLS token
+        feats = outputs.last_hidden_state  # [1, N, D]
+        cls_token = feats[:, 0]  # [1, D]
+        cls_token = cast(torch.Tensor, cls_token)
+
+        # 返回 Polars Series
+        return pl.Series("feature", cls_token.cpu().squeeze(0).tolist())
+
 
 if __name__ == "__main__":
     train_dataset = load_dataset("uoft-cs/cifar10", split="train")
-    train_dataset = cast(Dataset, train_dataset)
     label_map = [
         "airplane",
         "automobile",
diff --git a/mini-nav/visualizer/app.py b/mini-nav/visualizer/app.py
index 2425d5a..dc8bc6c 100644
--- a/mini-nav/visualizer/app.py
+++ b/mini-nav/visualizer/app.py
@@ -1,5 +1,5 @@
 import datetime
-from typing import Optional
+from typing import List, Optional, Union
 
 import dash_ag_grid as dag
 import dash_mantine_components as dmc
@@ -7,24 +7,6 @@ from dash import Dash, Input, Output, State, callback, dcc, html
 from database import db_manager
 
 
-def parse_contents(contents, filename, date):
-    return html.Div(
-        [
-            html.H5(filename),
-            html.H6(datetime.datetime.fromtimestamp(date)),
-            # HTML images accept base64 encoded strings in the same format
-            # that is supplied by the upload
-            html.Img(src=contents),
-            html.Hr(),
-            html.Div("Raw Content"),
-            html.Pre(
-                contents[0:200] + "...",
-                style={"whiteSpace": "pre-wrap", "wordBreak": "break-all"},
-            ),
-        ]
-    )
-
-
 class APP(Dash):
     """Singleton Dash Application"""
 
@@ -93,7 +75,22 @@ class APP(Dash):
         State("upload-image", "filename"),
         State("upload-image", "last_modified"),
     )
-    def update_output(list_of_contents, list_of_names, list_of_dates):
+    def update_output(
+        list_of_contents: List[str],
+        list_of_names: List[str],
+        list_of_dates: List[int] | List[float],
+    ):
+        def parse_contents(contents: str, filename: str, date: Union[int, float]):
+            return html.Div(
+                [
+                    html.H5(filename),
+                    html.H6(datetime.datetime.fromtimestamp(date)),
+                    # HTML images accept base64 encoded strings in the same format
+                    # that is supplied by the upload
+                    dmc.Image(src=contents),
+                ]
+            )
+
         if list_of_contents is not None:
             children = [
                 parse_contents(c, n, d)
diff --git a/pyproject.toml b/pyproject.toml
index 4af41db..119b52c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,3 +38,6 @@ torch = [
 torchvision = [
     { index = "pytorch-cu130", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
 ]
+
+[tool.ty.environment]
+root = ["./mini-nav"]