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import json
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import cv2
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import torch
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import torchvision.transforms.functional as TF
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import matplotlib.pyplot as plt
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from PIL import Image
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device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
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def load_vocab(vocab_path):
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with open(vocab_path, "r", encoding="utf-8") as f:
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vocab = json.load(f)
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char_to_idx = vocab["char_to_idx"]
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idx_to_char = {int(k): v for k, v in vocab["idx_to_char"].items()}
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return char_to_idx, idx_to_char
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def greedy_decode(output, idx_to_char):
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output = output.argmax(2)
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texts = []
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for seq in output:
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prev = -1
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chars = []
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for idx in seq.cpu().numpy():
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if idx != prev and idx != 0:
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chars.append(idx_to_char.get(idx, ""))
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prev = idx
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texts.append("".join(chars))
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return texts
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class OCRTestTransform:
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def __init__(self, img_height=64, max_width=1600):
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self.img_height = img_height
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self.max_width = max_width
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def __call__(self, img):
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img = img.convert("L")
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w, h = img.size
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new_w = int(w * self.img_height / h)
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img = img.resize((min(new_w, self.max_width), self.img_height), Image.BICUBIC)
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new_img = Image.new("L", (self.max_width, self.img_height), 255)
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new_img.paste(img, (0, 0))
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img = TF.to_tensor(new_img)
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img = TF.normalize(img, (0.5,), (0.5,))
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return img
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transform_test = OCRTestTransform()
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def segment_lines_precise(image_path, min_line_height=12, margin=6, visualize=False):
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img = cv2.imread(image_path, cv2.IMREAD_GRAYSCALE)
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_, binary = cv2.threshold(img, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)
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kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (img.shape[1]//30, 1))
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morphed = cv2.dilate(binary, kernel, iterations=1)
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contours, _ = cv2.findContours(morphed, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
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contours = sorted(contours, key=lambda ctr: cv2.boundingRect(ctr)[1])
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lines = []
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for ctr in contours:
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x, y, w, h = cv2.boundingRect(ctr)
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if h < min_line_height: continue
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y1 = max(0, y - margin)
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y2 = min(img.shape[0], y + h + margin)
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line_img = img[y1:y2, x:x+w]
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lines.append(Image.fromarray(line_img))
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if visualize:
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for i, line_img in enumerate(lines):
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plt.figure(figsize=(12,2))
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plt.imshow(line_img, cmap='gray')
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plt.axis('off')
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plt.title(f"Line {i+1}")
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plt.show()
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return lines
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def ocr_page(image_path, model, idx_to_char, visualize=False):
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lines = segment_lines_precise(image_path, visualize=visualize)
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all_texts = []
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for idx, line_img in enumerate(lines, 1):
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img_tensor = transform_test(line_img).unsqueeze(0).to(device)
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with torch.no_grad():
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outputs = model(img_tensor)
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pred_text = greedy_decode(outputs, idx_to_char)[0]
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all_texts.append(pred_text)
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print(f"Line {idx}: {pred_text}")
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return "\n".join(all_texts)
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