opencv_measurement_plugin 1.0.6

Real-time object measurement plugin with OpenCV for Flutter desktop applications. No external DLL required.

OpenCV Measurement Plugin

Real-time object detection and measurement plugin for Flutter desktop applications using OpenCV. No external DLL management required - everything is self-contained!

Donating money for food would be good That way I'll have motivation to keep developing/improving. KASIKORNBANK (Account number 1008151616)

🚀 Features

• Real-time camera feed with live object detection
• Ultra-precise measurements with sub-pixel accuracy
• Multiple detection modes (auto, color-based)
• Visual overlays showing detected objects and measurements
• Self-contained - includes all required OpenCV DLLs
• Cross-platform support for Windows, macOS, and Linux
• 30 FPS real-time processing
• BGR to RGBA automatic conversion for Flutter

📱 Platform Support

Platform	Support	Notes
Windows	✅ Full	Includes all OpenCV DLLs
macOS	✅ Full	Universal binary support
Linux	✅ Full	Tested on Ubuntu 20.04+
Android	❌	Not supported in this version
iOS	❌	Not supported in this version

📋 Requirements

• Flutter SDK 3.35.1 (recommended for optimal results)
• Dart 3.0.0 or higher
• Camera permission (automatically handled)

Note: While the plugin may work with other Flutter versions, version 3.35.1 is specifically tested and recommended for the best performance and compatibility.

🛠️ Installation

Add this to your package's pubspec.yaml file:

dependencies:
  opencv_measurement_plugin: ^1.0.3

Then run:

flutter pub get

🎯 Quick Start

import 'package:opencv_measurement_plugin/opencv_measurement_plugin.dart';

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final MeasurementService _service = MeasurementService();
  bool _isInitialized = false;

  @override
  void initState() {
    super.initState();
    _initializePlugin();
  }

  Future<void> _initializePlugin() async {
    final success = await _service.initialize();
    setState(() {
      _isInitialized = success;
    });

    // Listen to measurements
    _service.measurementStream.listen((data) {
      if (data.hasDetection) {
        print('Object: ${data.widthPx}x${data.heightPx} pixels');
        print('Confidence: ${(data.confidence * 100).toStringAsFixed(1)}%');
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: _isInitialized
          ? MeasurementCameraView(
              measurementService: _service,
              onMeasurementUpdate: (data) {
                // Handle measurement updates
              },
            )
          : Center(child: CircularProgressIndicator()),
    );
  }

  @override
  void dispose() {
    _service.dispose();
    super.dispose();
  }
}

📖 API Reference

MeasurementService

Main service class for object detection and measurement.

// Initialize the service
final service = MeasurementService();
await service.initialize();

// Start measurement
await service.start();

// Listen to measurements
service.measurementStream.listen((MeasurementData data) {
  if (data.hasDetection) {
    print('Width: ${data.widthPx} px');
    print('Height: ${data.heightPx} px');
  }
});

// Set detection mode
await service.setDetectionMode('auto'); // 'auto', 'blue', 'red', 'yellow'

// Stop measurement
service.stop();

MeasurementData

class MeasurementData {
  final double widthPx;        // Object width in pixels
  final double heightPx;       // Object height in pixels
  final double confidence;     // Detection confidence (0.0 to 1.0)
  final bool hasDetection;     // Whether object was detected
  final int frameWidth;        // Camera frame width
  final int frameHeight;       // Camera frame height
  final DateTime timestamp;    // Measurement timestamp
}

MeasurementCameraView

Widget for displaying camera feed with measurement overlays.

MeasurementCameraView(
  measurementService: _service,
  onMeasurementUpdate: (MeasurementData data) {
    // Handle real-time updates
  },
)

🔧 Advanced Usage

Detection Modes

// Available modes
await _service.setDetectionMode('auto');    // Automatic detection
await _service.setDetectionMode('blue');    // Detect blue objects
await _service.setDetectionMode('red');     // Detect red objects
await _service.setDetectionMode('yellow');  // Detect yellow objects
await _service.setDetectionMode('brown');   // Detect brown objects
await _service.setDetectionMode('white');   // Detect white objects

System Information

// Get system info
final info = _service.getSystemInfo();
print('OpenCV Version: ${info['opencv_version']}');
print('Camera Resolution: ${info['camera_resolution']}');

📊 Performance

• Real-time processing: 30 FPS camera feed
• Sub-pixel accuracy: Measurements accurate to 0.1 pixels
• Low latency: < 50ms processing time per frame
• Memory efficient: < 100MB RAM usage

🎨 Example Screenshots

Note: Add screenshots of your app using the plugin to show the visual overlays and measurement results.

🐛 Troubleshooting

Plugin fails to initialize:

• Make sure your app has camera permissions
• Check that your platform is supported (Windows/macOS/Linux)
• Verify Flutter version is 3.3.0 or higher

No camera feed:

• Verify camera is not being used by another application
• Check camera permissions in system settings
• Restart your application

Poor detection accuracy:

• Ensure good lighting conditions
• Use contrasting background colors
• Keep objects within the camera frame bounds
• Try different detection modes for better results

Build issues:

• Run flutter clean and flutter pub get
• Make sure you're targeting desktop platforms only
• Check that all required dependencies are installed

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

Development Setup

1. Fork the repository
2. Clone your fork: git clone https://github.com/permpree-vornthaisong/opencv_measurement_plugin.git
3. Install dependencies: flutter pub get
4. Run the example: cd example && flutter run

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

📞 Support

If you have any questions or issues:

• 📧 Create an issue on GitHub
• 📖 Check the documentation
• 💬 Join our community discussions

🙏 Acknowledgments

• OpenCV for the computer vision library
• Flutter for the amazing cross-platform framework
• The Flutter community for continuous support and feedback

---

Made with ❤️ for the Flutter community