Update app.py

app.py

@@ -385,7 +385,7 @@ def detect_paper_bounds(image: np.ndarray, paper_size: str, output_unit: str = "
         
         # Calculate scaling factor based on paper size with proper units
         # scaling_factor = calculate_paper_scaling_factor(paper_contour, paper_size, output_unit)
-        scaling_factor = calculate_paper_scaling_factor_corrected(
+        scaling_factor, unit_string = calculate_paper_scaling_factor_corrected(
             paper_contour, 
             paper_size, 
             output_unit="mm",