- A powerful open-source tool for automatic license plate recognition.
- Can process real-time video streams or image sequences.
- Provides accurate and reliable license plate detection and recognition.
- A lightweight Python web framework.
- Ideal for building RESTful APIs to handle requests from OpenALPR and serve real-time updates.
- Allows for easy integration with Redis and other databases.
- An in-memory data store used as a message broker for real-time updates.
- Provides efficient data storage and retrieval.
- Supports publishing and subscribing to channels, making it perfect for real-time applications.
- A server-push technology that enables the server to send event streams to clients without the need for polling.
- Ideal for real-time updates, such as new license plate detections.
- Video Input:
- The system can ingest video feeds from various sources like IP cameras, local files, or live streams.
- OpenALPR:
- OpenALPR, a powerful open-source automatic license plate recognition software, processes the video frames to detect and recognize license plates.
- Flask Application:
- The Flask application acts as an API endpoint to receive the recognized license plates from OpenALPR. It stores the license plate information in a Redis database.
- Redis Database:
- Redis is used to store the recognized license plates and act as a message broker for real-time updates.
- Server-Sent Events (SSE):
- SSE is used to push real-time updates from the server to the client-side applications. Clients can subscribe to the SSE endpoint to receive notifications whenever a new license plate is detected.
- Set up the Environment:
- Install Python, Flask, Redis, and OpenALPR.
- Configure OpenALPR to send recognized license plates to your Flask API endpoint.
- Create the Flask Application:
- Define an API endpoint to receive license plate data from OpenALPR.
- Store the received data in Redis.
- Implement an SSE endpoint to push real-time updates to clients.
- Configure Redis:
- Set up a Redis server and configure your application to connect to it. Use Redis's data structures (e.g., Hash, List) to store license plate information and track active clients.
- Client-Side Implementation:
-
Create a web application or a script to connect to the SSE endpoint.
-
Upon receiving updates, display the new license plate information on the client-side.
-
Web Application:
- Use JavaScript and the EventSource API to connect to the SSE endpoint and receive real-time updates.
-
Mobile App:
- Implement a similar approach using platform-specific libraries for network requests and UI updates.
from flask import Flask, jsonify, Response
import redis
app = Flask(__name__)
redis_client = redis.Redis(host='localhost', port=6379, db=0)
@app.route('/alpr_data', methods=['POST'])
def receive_alpr_data():
data = request.json
license_plate = data['plate']
redis_client.publish('license_plates', license_plate)
return jsonify({'status': 'success'})
@app.route('/stream')
def stream():
def generate():
pubsub = redis_client.pubsub()
pubsub.subscribe('license_plates')
for message in pubsub.listen():
if message['type'] == 'message':
yield f"data: {message['data'].decode('utf-8')}\n\n"
return Response(generate(), mimetype='text/event-stream')
if __name__ == '__main__':
app.run(debug=True)
- Scalability: For high-traffic applications, consider using a robust message broker like RabbitMQ or Kafka.
- Security: Implement appropriate security measures to protect your system from unauthorized access.
- Performance: Optimize the system for real-time performance, especially if dealing with a large number of video feeds.
- Error Handling: Implement robust error handling and logging to identify and troubleshoot issues.
Get the Source code:https://github.com/micrometre/flaskalpr.git