Интеграция Azure Computer Vision OCR

Интеграция Azure Computer Vision OCR

Azure Computer Vision предоставляет два OCR-сервиса: Read API (оптимизирован для плотных документов, рекомендуется Microsoft) и старый OCR API (только для простых изображений). Read API 4.0 работает как на cloud, так и в виде контейнера для on-premise развёртывания.

Интеграция Read API

from azure.cognitiveservices.vision.computervision import ComputerVisionClient
from azure.cognitiveservices.vision.computervision.models import OperationStatusCodes
from msrest.authentication import CognitiveServicesCredentials
import time

class AzureOCR:
    def __init__(self, endpoint: str, api_key: str):
        self.client = ComputerVisionClient(
            endpoint,
            CognitiveServicesCredentials(api_key)
        )

    def extract_text_from_url(self, image_url: str) -> str:
        """Read API: асинхронная обработка через URL"""
        read_response = self.client.read_in_stream(
            open('image.jpg', 'rb'),
            raw=True
        )

        # Получаем operation ID из заголовка
        operation_location = read_response.headers['Operation-Location']
        operation_id = operation_location.split('/')[-1]

        # Ожидание результата
        while True:
            read_result = self.client.get_read_result(operation_id)
            if read_result.status not in [
                OperationStatusCodes.running,
                OperationStatusCodes.not_started
            ]:
                break
            time.sleep(0.5)

        # Извлечение текста
        text_lines = []
        if read_result.status == OperationStatusCodes.succeeded:
            for page in read_result.analyze_result.read_results:
                for line in page.lines:
                    text_lines.append(line.text)

        return '\n'.join(text_lines)

    def extract_with_positions(self, image_path: str) -> list[dict]:
        """Извлечение с координатами bounding boxes"""
        with open(image_path, 'rb') as f:
            read_response = self.client.read_in_stream(f, raw=True)

        operation_id = read_response.headers['Operation-Location'].split('/')[-1]

        while True:
            result = self.client.get_read_result(operation_id)
            if result.status not in [OperationStatusCodes.running,
                                       OperationStatusCodes.not_started]:
                break
            time.sleep(0.3)

        words = []
        if result.status == OperationStatusCodes.succeeded:
            for page in result.analyze_result.read_results:
                for line in page.lines:
                    for word in line.words:
                        words.append({
                            'text': word.text,
                            'confidence': word.confidence,
                            'bbox': word.bounding_box  # [x1,y1,x2,y1,x2,y2,x1,y2]
                        })
        return words

Document Intelligence (бывший Form Recognizer)

Для структурированных документов (счета, договоры, удостоверения) Azure Document Intelligence значительно мощнее базового OCR:

from azure.ai.formrecognizer import DocumentAnalysisClient
from azure.core.credentials import AzureKeyCredential

class AzureDocumentIntelligence:
    def __init__(self, endpoint: str, api_key: str):
        self.client = DocumentAnalysisClient(
            endpoint=endpoint,
            credential=AzureKeyCredential(api_key)
        )

    def analyze_invoice(self, image_path: str) -> dict:
        """Специализированный анализ инвойсов"""
        with open(image_path, 'rb') as f:
            poller = self.client.begin_analyze_document(
                'prebuilt-invoice', f
            )

        result = poller.result()
        invoices = []

        for invoice in result.documents:
            fields = invoice.fields
            invoices.append({
                'vendor_name': fields.get('VendorName', {}).get('value'),
                'invoice_date': str(fields.get('InvoiceDate', {}).get('value')),
                'total_amount': fields.get('AmountDue', {}).get('value'),
                'invoice_id': fields.get('InvoiceId', {}).get('value'),
                'line_items': [
                    {
                        'description': item.get('Description', {}).get('value'),
                        'amount': item.get('Amount', {}).get('value')
                    }
                    for item in (fields.get('Items', {}).get('value') or [])
                ]
            })

        return invoices[0] if invoices else {}

On-premise контейнер

Для данных с требованием локальной обработки — Read API Container:

docker run --rm -it -p 5000:5000 \
  -e ApiKey=YOUR_KEY \
  -e Billing=YOUR_ENDPOINT \
  mcr.microsoft.com/azure-cognitive-services/vision/read:3.2

Контейнер работает идентично cloud API, но данные не покидают инфраструктуру.

Сравнение Read API vs Document Intelligence