Apply light preprocessing by default (grayscale, denoise, contrast=5) to improve OCR readability

ui_components.py

@@ -131,19 +131,19 @@ def create_sidebar_options():
             
             # Grayscale conversion
             grayscale = st.checkbox("Convert to Grayscale", 
-                                  value=False,
+                                  value=True,
                                   help="Convert color images to grayscale for better text recognition")
             
             # Light denoising option
             denoise = st.checkbox("Light Denoising", 
-                                value=False,
+                                value=True,
                                 help="Apply gentle denoising to improve text clarity")
             
             # Contrast adjustment
             contrast = st.slider("Contrast Adjustment", 
                                min_value=-20, 
                                max_value=20, 
-                               value=0,
+                               value=5,
                                step=5,
                                help="Adjust image contrast (limited range)")