smart-ocr（智能文字识别）

Smart OCR Skill

Overview

This skill enables intelligent text extraction from images and scanned documents using PaddleOCR - a leading OCR engine supporting 100+ languages. Extract text from photos, screenshots, scanned PDFs, and handwritten documents with high accuracy.

How to Use

1. Provide the image or scanned document
2. Optionally specify language(s) to detect
3. I'll extract text with position and confidence data

Example prompts:

• "Extract all text from this screenshot"
• "OCR this scanned PDF document"
• "Read the text from this business card photo"
• "Extract Chinese and English text from this image"

Domain Knowledge

PaddleOCR Fundamentals

from paddleocr import PaddleOCR

# Initialize OCR engine
ocr = PaddleOCR(use_angle_cls=True, lang='en')

# Run OCR on image
result = ocr.ocr('image.png', cls=True)

# Result structure: [[box, (text, confidence)], ...]
for line in result[0]:
    box = line[0]      # [[x1,y1], [x2,y2], [x3,y3], [x4,y4]]
    text = line[1][0]  # Extracted text
    conf = line[1][1]  # Confidence score
    print(f"{text} ({conf:.2f})")

Supported Languages

# Common language codes
languages = {
    'en': 'English',
    'ch': 'Chinese (Simplified)',
    'cht': 'Chinese (Traditional)',
    'japan': 'Japanese',
    'korean': 'Korean',
    'french': 'French',
    'german': 'German',
    'spanish': 'Spanish',
    'russian': 'Russian',
    'arabic': 'Arabic',
    'hindi': 'Hindi',
    'vi': 'Vietnamese',
    'th': 'Thai',
    # ... 100+ languages supported
}

# Use specific language
ocr = PaddleOCR(lang='ch')  # Chinese
ocr = PaddleOCR(lang='japan')  # Japanese
ocr = PaddleOCR(lang='multilingual')  # Auto-detect

Configuration Options

from paddleocr import PaddleOCR

ocr = PaddleOCR(
    # Detection settings
    det_model_dir=None,         # Custom detection model
    det_limit_side_len=960,     # Max side length for detection
    det_db_thresh=0.3,          # Binarization threshold
    det_db_box_thresh=0.5,      # Box score threshold

    # Recognition settings
    rec_model_dir=None,         # Custom recognition model
    rec_char_dict_path=None,    # Custom character dictionary

    # Angle classification
    use_angle_cls=True,         # Enable angle classification
    cls_model_dir=None,         # Custom classification model

    # Language
    lang='en',                  # Language code

    # Performance
    use_gpu=True,               # Use GPU if available
    gpu_mem=500,                # GPU memory limit (MB)
    enable_mkldnn=True,         # CPU optimization

    # Output
    show_log=False,             # Suppress logs
)

Processing Different Sources

Image Files

# Single image
result = ocr.ocr('image.png')

# Multiple images
images = ['img1.png', 'img2.png', 'img3.png']
for img in images:
    result = ocr.ocr(img)
    process_result(result)

PDF Files (Scanned)

from pdf2image import convert_from_path

def ocr_pdf(pdf_path):
    """OCR a scanned PDF."""
    # Convert PDF pages to images
    images = convert_from_path(pdf_path)

    all_text = []
    for i, img in enumerate(images):
        # Save temp image
        temp_path = f'temp_page_{i}.png'
        img.save(temp_path)

        # OCR the image
        result = ocr.ocr(temp_path)

        # Extract text
        page_text = '\n'.join([line[1][0] for line in result[0]])
        all_text.append(f"--- Page {i+1} ---\n{page_text}")

        os.remove(temp_path)

    return '\n\n'.join(all_text)

URLs and Bytes

import requests
from io import BytesIO

# From URL
response = requests.get('https://example.com/image.png')
result = ocr.ocr(BytesIO(response.content))

# From bytes
with open('image.png', 'rb') as f:
    img_bytes = f.read()
result = ocr.ocr(BytesIO(img_bytes))

Result Processing

def process_ocr_result(result):
    """Process OCR result into structured data."""

    lines = []
    for line in result[0]:
        box = line[0]
        text = line[1][0]
        confidence = line[1][1]

        # Calculate bounding box
        x_coords = [p[0] for p in box]
        y_coords = [p[1] for p in box]

        lines.append({
            'text': text,
            'confidence': confidence,
            'bbox': {
                'left': min(x_coords),
                'top': min(y_coords),
                'right': max(x_coords),
                'bottom': max(y_coords),
            },
            'raw_box': box
        })

    return lines

# Sort by position (top to bottom, left to right)
def sort_by_position(lines):
    return sorted(lines, key=lambda x: (x['bbox']['top'], x['bbox']['left']))

Text Layout Reconstruction

def reconstruct_layout(result, line_threshold=10):
    """Reconstruct text layout from OCR results."""

    lines = process_ocr_result(result)
    lines = sort_by_position(lines)

    # Group into logical lines
    text_lines = []
    current_line = []
    current_y = None

    for line in lines:
        y = line['bbox']['top']

        if current_y is None or abs(y - current_y) < line_threshold:
            current_line.append(line)
            current_y = y
        else:
            # New line
            text_lines.append(' '.join([l['text'] for l in current_line]))
            current_line = [line]
            current_y = y

    # Add last line
    if current_line:
        text_lines.append(' '.join([l['text'] for l in current_line]))

    return '\n'.join(text_lines)

Best Practices

1. Preprocess Images: Improve quality before OCR
2. Choose Correct Language: Specify language for better accuracy
3. Handle Multi-column: Process columns separately
4. Filter Low Confidence: Skip results below threshold
5. Batch Processing: Process multiple images efficiently

Common Patterns

Image Preprocessing

from PIL import Image, ImageEnhance, ImageFilter

def preprocess_image(image_path):
    """Preprocess image for better OCR."""
    img = Image.open(image_path)

    # Convert to grayscale
    img = img.convert('L')

    # Enhance contrast
    enhancer = ImageEnhance.Contrast(img)
    img = enhancer.enhance(2.0)

    # Sharpen
    img = img.filter(ImageFilter.SHARPEN)

    # Save preprocessed
    preprocessed_path = 'preprocessed.png'
    img.save(preprocessed_path)

    return preprocessed_path

Batch OCR with Progress

from tqdm import tqdm
from concurrent.futures import ThreadPoolExecutor

def batch_ocr(image_paths, max_workers=4):
    """OCR multiple images in parallel."""

    results = {}

    def process_single(img_path):
        result = ocr.ocr(img_path)
        return img_path, result

    with ThreadPoolExecutor(max_workers=max_workers) as executor:
        futures = [executor.submit(process_single, p) for p in image_paths]

        for future in tqdm(futures, desc="Processing OCR"):
            path, result = future.result()
            results[path] = result

    return results

Examples

Example 1: Business Card Reader

from paddleocr import PaddleOCR
import re

def read_business_card(image_path):
    """Extract contact info from business card."""

    ocr = PaddleOCR(use_angle_cls=True, lang='en')
    result = ocr.ocr(image_path)

    # Extract all text
    all_text = []
    for line in result[0]:
        all_text.append(line[1][0])

    full_text = '\n'.join(all_text)

    # Parse contact info
    contact = {
        'name': None,
        'email': None,
        'phone': None,
        'company': None,
        'title': None,
        'raw_text': full_text
    }

    # Email pattern
    email_match = re.search(r'[\w\.-]+@[\w\.-]+\.\w+', full_text)
    if email_match:
        contact['email'] = email_match.group()

    # Phone pattern
    phone_match = re.search(r'[\+\d][\d\s\-\(\)]{8,}', full_text)
    if phone_match:
        contact['phone'] = phone_match.group().strip()

    # Name is usually the largest/first text
    if all_text:
        contact['name'] = all_text[0]

    return contact

card_info = read_business_card('business_card.jpg')
print(f"Name: {card_info['name']}")
print(f"Email: {card_info['email']}")
print(f"Phone: {card_info['phone']}")

Example 2: Receipt Scanner

from paddleocr import PaddleOCR
import re

def scan_receipt(image_path):
    """Extract items and total from receipt."""

    ocr = PaddleOCR(use_angle_cls=True, lang='en')
    result = ocr.ocr(image_path)

    lines = []
    for line in result[0]:
        text = line[1][0]
        y_pos = line[0][0][1]
        lines.append({'text': text, 'y': y_pos})

    # Sort by vertical position
    lines.sort(key=lambda x: x['y'])

    receipt = {
        'items': [],
        'subtotal': None,
        'tax': None,
        'total': None
    }

    for line in lines:
        text = line['text']

        # Look for total
        if 'total' in text.lower():
            amount = re.search(r'\$?([\d,]+\.?\d*)', text)
            if amount:
                if 'sub' in text.lower():
                    receipt['subtotal'] = float(amount.group(1).replace(',', ''))
                else:
                    receipt['total'] = float(amount.group(1).replace(',', ''))

        # Look for tax
        elif 'tax' in text.lower():
            amount = re.search(r'\$?([\d,]+\.?\d*)', text)
            if amount:
                receipt['tax'] = float(amount.group(1).replace(',', ''))

        # Look for items (line with price)
        else:
            item_match = re.search(r'(.+?)\s+\$?([\d,]+\.?\d+)$', text)
            if item_match:
                receipt['items'].append({
                    'name': item_match.group(1).strip(),
                    'price': float(item_match.group(2).replace(',', ''))
                })

    return receipt

receipt_data = scan_receipt('receipt.jpg')
print(f"Items: {len(receipt_data['items'])}")
print(f"Total: ${receipt_data['total']}")

Example 3: Multi-language Document

from paddleocr import PaddleOCR

def ocr_multilingual(image_path, languages=['en', 'ch']):
    """OCR document with multiple languages."""

    all_results = {}

    for lang in languages:
        ocr = PaddleOCR(use_angle_cls=True, lang=lang)
        result = ocr.ocr(image_path)

        texts = []
        for line in result[0]:
            texts.append({
                'text': line[1][0],
                'confidence': line[1][1]
            })

        all_results[lang] = texts

    # Merge results, keeping highest confidence
    merged = {}
    for lang, texts in all_results.items():
        for item in texts:
            text = item['text']
            conf = item['confidence']

            if text not in merged or merged[text]['confidence'] < conf:
                merged[text] = {'confidence': conf, 'language': lang}

    return merged

result = ocr_multilingual('bilingual_document.png')
for text, info in result.items():
    print(f"[{info['language']}] {text} ({info['confidence']:.2f})")

Limitations

• Handwritten text accuracy varies
• Very small text may not be detected
• Complex backgrounds reduce accuracy
• Rotated text needs angle classification
• GPU recommended for best performance

Installation

# CPU version
pip install paddlepaddle paddleocr

# GPU version (CUDA 11.x)
pip install paddlepaddle-gpu paddleocr

# Additional dependencies
pip install pdf2image Pillow

Resources

• PaddleOCR GitHub
• Model Zoo
• Multi-language Support