From a641682cc19de970d8a9a35d6255ddb91cbcc735 Mon Sep 17 00:00:00 2001
From: khushanuma-shabbir <khushanuma.shabbir@gmail.com>
Date: Tue, 19 May 2026 00:31:11 +0530
Subject: [PATCH] Fix: add confidence threshold and prevent UI freezing on
 empty states

---
 app.py               | 67 ++++++++++++++++++++++++++------------------
 templates/index.html |  8 ++++--
 2 files changed, 46 insertions(+), 29 deletions(-)

diff --git a/app.py b/app.py
index c3160be..920e494 100644
--- a/app.py
+++ b/app.py
@@ -34,6 +34,7 @@
 last_letter = ""
 letter_start_time = None
 auto_add_delay = 5
+CONFIDENCE_THRESHOLD = 0.70  # Minimum 70% confidence required
 
 
 @app.route('/')
@@ -90,9 +91,13 @@ def predict():
             imgCrop = img[y1:y2, x1:x2]
 
             if imgCrop.size == 0:
-
+                last_letter = ""
+                letter_start_time = None
                 return jsonify({
-                    "success": False
+                    "success": True,
+                    "letter": "Waiting...",
+                    "confidence": 0.0,
+                    "word": word
                 })
 
             aspectRatio = h / w
@@ -137,43 +142,51 @@ def predict():
             )
 
             current_letter = labels[index]
-
             confidence = prediction[index]
 
-            # Auto add letter logic
-            if current_letter == last_letter:
-
-                if (
-                    letter_start_time and
-                    time.time() - letter_start_time >= auto_add_delay
-                ):
-
-                    word += current_letter
-
-                    letter_start_time = None
-                    last_letter = ""
+            if confidence >= CONFIDENCE_THRESHOLD:
+                # Auto add letter logic
+                if current_letter == last_letter:
+                    if (
+                        letter_start_time and
+                        time.time() - letter_start_time >= auto_add_delay
+                    ):
+                        word += current_letter
+                        letter_start_time = None
+                        last_letter = ""
+                else:
+                    last_letter = current_letter
+                    letter_start_time = time.time()
 
+                return jsonify({
+                    "success": True,
+                    "letter": current_letter,
+                    "confidence": float(confidence),
+                    "word": word
+                })
             else:
-
-                last_letter = current_letter
-                letter_start_time = time.time()
-
-            return jsonify({
-                "success": True,
-                "letter": current_letter,
-                "confidence": float(confidence),
-                "word": word
-            })
+                # Reset tracking if confidence is too low (e.g., hand transition)
+                last_letter = ""
+                letter_start_time = None
+                return jsonify({
+                    "success": True,
+                    "letter": "Unsure",
+                    "confidence": float(confidence),
+                    "word": word
+                })
 
         else:
-
             current_letter = ""
             confidence = 0.0
             last_letter = ""
             letter_start_time = None
 
+            # Return success: True so the frontend updates to "Waiting..."
             return jsonify({
-                "success": False
+                "success": True,
+                "letter": "Waiting...",
+                "confidence": 0.0,
+                "word": word
             })
 
     except Exception as e:
diff --git a/templates/index.html b/templates/index.html
index cf81b53..39a731e 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -376,8 +376,12 @@
 
             if(data.success){
 
-                currentLetter.textContent =
-                    `${data.letter} (${Math.round(data.confidence * 100)}%)`;
+                if (data.letter === "Waiting..." || data.letter === "Unsure") {
+                    currentLetter.textContent = data.letter;
+                } else {
+                    currentLetter.textContent =
+                        `${data.letter} (${Math.round(data.confidence * 100)}%)`;
+                }
 
                 document.getElementById(
                     'displayWord'