Fix model parameters

app.py

@@ -100,12 +100,12 @@ with col2:
 with col3:
     # set SAHI parameters
     st.markdown('##### Set model parameters')
-    slice_size = st.slider(
-        label = 'Slice Size', 
-        min_value=1240,
-        max_value=4960, 
-        value=2480, 
-        step=1240
+    slice_size_percentage = st.slider(
+        label = 'Slice Size %', 
+        min_value=0.25,
+        max_value=1, 
+        value=0.5, 
+        step=0.25
     )
     overlap_ratio = st.slider(
         label = 'Overlap Ratio', 
@@ -133,6 +133,7 @@ if submit:
     with st.spinner(text="Downloading model weights ... "):
         detection_model = get_model(postprocess_match_threshold)
         
+    slice_size = (slice_size_percentage/0.25) * 1240
     image_size = 4960
 
     with st.spinner(text="Performing prediction ... "):