added check for failed detections

app.py

@@ -6,7 +6,7 @@ import tensorflow as tf
 from PIL import Image
 from fastapi import FastAPI, File, UploadFile
 from fastapi.middleware.cors import CORSMiddleware
-from fastapi.responses import StreamingResponse
+from fastapi.responses import StreamingResponse, Response 
 from huggingface_hub import hf_hub_download, snapshot_download, login
 
 # 1. Run environment fixes immediately
@@ -69,15 +69,20 @@ async def predict(file: UploadFile = File(...)):
     with graph.as_default():
         results = model_eval.detect([image_np], verbose=0)
     
-    # Process Image
-    import cv2
+    # --- ADD THIS CHECK ---
+    # results[0] contains 'rois', 'masks', 'class_ids', and 'scores'
+    if len(results[0]['scores']) == 0:
+        # Returning a 204 status triggers 'response.status === 204' in your React code
+        return Response(status_code=204)
+    # ----------------------
+
+    # Process Image (Only happens if segments exist)
     processed_img = visualize_detections(image_np, results)
-    
+        
     # Return Stream
     _, buffer = cv2.imencode('.jpg', processed_img)
     return StreamingResponse(io.BytesIO(buffer), media_type="image/jpeg")
 
-
 @app.post("/explain/occlusion")
 async def explain_occlusion(file: UploadFile = File(...)):
     # 1. Load and Downsample