Update ocr_engine.py

ocr_engine.py

@@ -35,22 +35,22 @@ def preprocess_image(img):
     """Preprocess image with aggressive contrast and noise handling."""
     gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
     brightness = estimate_brightness(img)
-    # Maximum CLAHE for extreme contrast
-    clahe_clip = 10.0 if brightness < 80 else 6.0
-    clahe = cv2.createCLAHE(clipLimit=clahe_clip, tileGridSize=(6, 6))
+    # Maximum CLAHE with adjusted clip for better digit enhancement
+    clahe_clip = 12.0 if brightness < 80 else 8.0
+    clahe = cv2.createCLAHE(clipLimit=clahe_clip, tileGridSize=(4, 4))
     enhanced = clahe.apply(gray)
     save_debug_image(enhanced, "01_preprocess_clahe")
-    # Edge-preserving blur
-    blurred = cv2.bilateralFilter(enhanced, 5, 75, 75)
+    # Stronger edge-preserving blur
+    blurred = cv2.bilateralFilter(enhanced, 7, 100, 100)
     save_debug_image(blurred, "02_preprocess_blur")
-    # Adaptive thresholding with small blocks
-    block_size = max(5, min(15, int(img.shape[0] / 30) * 2 + 1))
+    # Adaptive thresholding with smaller blocks
+    block_size = max(3, min(11, int(img.shape[0] / 40) * 2 + 1))
     thresh = cv2.adaptiveThreshold(blurred, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, 
-                                   cv2.THRESH_BINARY_INV, block_size, 3)
-    # Morphological operations for digit segmentation
+                                   cv2.THRESH_BINARY_INV, block_size, 2)
+    # Morphological operations for robust digit segmentation
     kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (3, 3))
     thresh = cv2.morphologyEx(thresh, cv2.MORPH_OPEN, kernel, iterations=1)
-    thresh = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel, iterations=5)
+    thresh = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel, iterations=6)
     save_debug_image(thresh, "03_preprocess_morph")
     return thresh, enhanced
 
@@ -58,12 +58,12 @@ def correct_rotation(img):
     """Correct image rotation using edge detection."""
     try:
         gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
-        edges = cv2.Canny(gray, 20, 80, apertureSize=3)
-        lines = cv2.HoughLinesP(edges, 1, np.pi / 180, threshold=30, minLineLength=15, maxLineGap=5)
+        edges = cv2.Canny(gray, 15, 60, apertureSize=3)
+        lines = cv2.HoughLinesP(edges, 1, np.pi / 180, threshold=20, minLineLength=10, maxLineGap=3)
         if lines is not None:
             angles = [np.arctan2(line[0][3] - line[0][1], line[0][2] - line[0][0]) * 180 / np.pi for line in lines]
             angle = np.median(angles)
-            if abs(angle) > 0.3:
+            if abs(angle) > 0.2:
                 h, w = img.shape[:2]
                 center = (w // 2, h // 2)
                 M = cv2.getRotationMatrix2D(center, angle, 1.0)
@@ -81,15 +81,15 @@ def detect_roi(img):
         save_debug_image(img, "04_original")
         thresh, enhanced = preprocess_image(img)
         brightness_map = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
-        block_sizes = [max(5, min(15, int(img.shape[0] / s) * 2 + 1)) for s in [6, 10, 15]]
+        block_sizes = [max(3, min(11, int(img.shape[0] / s) * 2 + 1)) for s in [4, 8, 12]]
         valid_contours = []
         img_area = img.shape[0] * img.shape[1]
         
         for block_size in block_sizes:
             temp_thresh = cv2.adaptiveThreshold(enhanced, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, 
-                                               cv2.THRESH_BINARY_INV, block_size, 3)
+                                               cv2.THRESH_BINARY_INV, block_size, 2)
             kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (5, 5))
-            temp_thresh = cv2.morphologyEx(temp_thresh, cv2.MORPH_CLOSE, kernel, iterations=5)
+            temp_thresh = cv2.morphologyEx(temp_thresh, cv2.MORPH_CLOSE, kernel, iterations=6)
             save_debug_image(temp_thresh, f"05_roi_threshold_block{block_size}")
             contours, _ = cv2.findContours(temp_thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
             
@@ -98,15 +98,15 @@ def detect_roi(img):
                 x, y, w, h = cv2.boundingRect(c)
                 roi_brightness = np.mean(brightness_map[y:y+h, x:x+w])
                 aspect_ratio = w / h
-                if (200 < area < (img_area * 0.7) and 
-                    0.2 <= aspect_ratio <= 10.0 and w > 50 and h > 20 and roi_brightness > 40):
+                if (150 < area < (img_area * 0.8) and 
+                    0.15 <= aspect_ratio <= 12.0 and w > 40 and h > 15 and roi_brightness > 30):
                     valid_contours.append((c, area * roi_brightness))
                     logging.debug(f"Contour (block {block_size}): Area={area}, Aspect={aspect_ratio:.2f}, Brightness={roi_brightness:.2f}")
         
         if valid_contours:
             contour, _ = max(valid_contours, key=lambda x: x[1])
             x, y, w, h = cv2.boundingRect(contour)
-            padding = max(15, min(40, int(min(w, h) * 0.3)))
+            padding = max(10, min(30, int(min(w, h) * 0.25)))
             x, y = max(0, x - padding), max(0, y - padding)
             w, h = min(w + 2 * padding, img.shape[1] - x), min(h + 2 * padding, img.shape[0] - y)
             roi_img = img[y:y+h, x:x+w]
@@ -123,14 +123,14 @@ def detect_roi(img):
         return img, None
 
 def detect_digit_template(digit_img, brightness):
-    """Digit recognition using template matching with predefined patterns."""
+    """Digit recognition using template matching with adjusted patterns."""
     try:
         h, w = digit_img.shape
-        if h < 10 or w < 5:
+        if h < 8 or w < 4:
             logging.debug("Digit image too small for template matching.")
             return None
 
-        # Predefined digit templates (simplified binary patterns)
+        # Adjusted digit templates for seven-segment display
         digit_templates = {
             '0': np.array([[1, 1, 1, 1, 1],
                            [1, 0, 0, 0, 1],
@@ -143,29 +143,29 @@ def detect_digit_template(digit_img, brightness):
                            [0, 0, 1, 0, 0],
                            [0, 0, 1, 0, 0]]),
             '2': np.array([[1, 1, 1, 1, 1],
-                           [0, 0, 0, 0, 1],
+                           [0, 0, 0, 1, 1],
                            [1, 1, 1, 1, 1],
-                           [1, 0, 0, 0, 0],
+                           [1, 1, 0, 0, 0],
                            [1, 1, 1, 1, 1]]),
             '3': np.array([[1, 1, 1, 1, 1],
-                           [0, 0, 0, 0, 1],
-                           [1, 1, 1, 1, 1],
-                           [0, 0, 0, 0, 1],
+                           [0, 0, 0, 1, 1],
+                           [0, 1, 1, 1, 1],
+                           [0, 0, 0, 1, 1],
                            [1, 1, 1, 1, 1]]),
-            '4': np.array([[1, 0, 0, 0, 1],
-                           [1, 0, 0, 0, 1],
+            '4': np.array([[1, 1, 0, 0, 1],
+                           [1, 1, 0, 0, 1],
                            [1, 1, 1, 1, 1],
                            [0, 0, 0, 0, 1],
                            [0, 0, 0, 0, 1]]),
             '5': np.array([[1, 1, 1, 1, 1],
-                           [1, 0, 0, 0, 0],
+                           [1, 1, 0, 0, 0],
                            [1, 1, 1, 1, 1],
-                           [0, 0, 0, 0, 1],
+                           [0, 0, 0, 1, 1],
                            [1, 1, 1, 1, 1]]),
             '6': np.array([[1, 1, 1, 1, 1],
-                           [1, 0, 0, 0, 0],
+                           [1, 1, 0, 0, 0],
                            [1, 1, 1, 1, 1],
-                           [1, 0, 0, 0, 1],
+                           [1, 0, 0, 1, 1],
                            [1, 1, 1, 1, 1]]),
             '7': np.array([[1, 1, 1, 1, 1],
                            [0, 0, 0, 0, 1],
@@ -180,7 +180,7 @@ def detect_digit_template(digit_img, brightness):
             '9': np.array([[1, 1, 1, 1, 1],
                            [1, 0, 0, 0, 1],
                            [1, 1, 1, 1, 1],
-                           [0, 0, 0, 0, 1],
+                           [0, 0, 0, 1, 1],
                            [1, 1, 1, 1, 1]]),
             '.': np.array([[0, 0, 0],
                            [0, 1, 0],
@@ -195,11 +195,11 @@ def detect_digit_template(digit_img, brightness):
                 digit_img_resized = cv2.resize(digit_img, (3, 3), interpolation=cv2.INTER_NEAREST)
             result = cv2.matchTemplate(digit_img_resized, template, cv2.TM_CCOEFF_NORMED)
             _, max_val, _, _ = cv2.minMaxLoc(result)
-            if max_val > 0.7 and max_val > best_score:
+            if max_val > 0.65 and max_val > best_score:  # Lowered threshold for better match
                 best_score = max_val
                 best_match = digit
         logging.debug(f"Template match: {best_match}, Score: {best_score:.2f}")
-        return best_match if best_score > 0.7 else None
+        return best_match if best_score > 0.65 else None
     except Exception as e:
         logging.error(f"Template digit detection failed: {str(e)}")
         return None
@@ -234,7 +234,7 @@ def perform_ocr(img, roi_bbox):
         digits_info = []
         for c in contours:
             x, y, w, h = cv2.boundingRect(c)
-            if w > 8 and h > 10 and 0.1 <= w/h <= 2.0:
+            if w > 6 and h > 8 and 0.1 <= w/h <= 2.5:  # Loosened size and aspect ratio
                 digits_info.append((x, x+w, y, y+h))
         
         if digits_info:
@@ -251,7 +251,7 @@ def perform_ocr(img, roi_bbox):
                 digit = detect_digit_template(digit_crop, brightness)
                 if digit:
                     recognized_text += digit
-                elif x_min - prev_x_max < 8 and prev_x_max != -float('inf'):
+                elif x_min - prev_x_max < 6 and prev_x_max != -float('inf'):  # Adjusted decimal gap
                     recognized_text += '.'
                 prev_x_max = x_max
             
@@ -279,11 +279,11 @@ def extract_weight_from_image(pil_img):
         save_debug_image(img, "00_input_image")
         img = correct_rotation(img)
         brightness = estimate_brightness(img)
-        conf_threshold = 0.8 if brightness > 100 else 0.6
+        conf_threshold = 0.75 if brightness > 100 else 0.55  # Lowered threshold
 
         roi_img, roi_bbox = detect_roi(img)
         if roi_bbox:
-            conf_threshold *= 1.05 if (roi_bbox[2] * roi_bbox[3]) > (img.shape[0] * img.shape[1] * 0.2) else 1.0
+            conf_threshold *= 1.05 if (roi_bbox[2] * roi_bbox[3]) > (img.shape[0] * img.shape[1] * 0.15) else 1.0
 
         result, confidence = perform_ocr(roi_img, roi_bbox)
         if result and confidence >= conf_threshold * 100:
@@ -298,7 +298,7 @@ def extract_weight_from_image(pil_img):
 
         logging.info("Primary OCR failed, using full image fallback.")
         result, confidence = perform_ocr(img, None)
-        if result and confidence >= conf_threshold * 0.85 * 100:
+        if result and confidence >= conf_threshold * 0.8 * 100:  # Adjusted fallback threshold
             try:
                 weight = float(result)
                 if 0.01 <= weight <= 1000: