@osobh/reactar/src/sensors/SLAM.ts

AR Library for React Native and Expo

// src/sensors/SLAM.ts

import { DeviceTracking, SensorData } from './DeviceTracking';
import { EnvironmentalDetection, Plane, Anchor } from './EnvironmentalDetection';

interface Feature {
  id: string;
  position: { x: number; y: number; z: number };
  descriptor: number[]; // Feature descriptor for matching
  lastSeen: number; // Timestamp
}

interface MapPoint {
  id: string;
  position: { x: number; y: number; z: number };
  observations: Feature[];
  confidence: number;
}

export class SLAM {
  private deviceTracking: DeviceTracking;
  private environmentalDetection: EnvironmentalDetection;
  private features: Map<string, Feature> = new Map();
  private mapPoints: Map<string, MapPoint> = new Map();
  private lastPose: { position: SensorData; orientation: SensorData } | null = null;

  constructor() {
    this.deviceTracking = new DeviceTracking();
    this.environmentalDetection = new EnvironmentalDetection();
  }

  async initialize(): Promise<void> {
    // Start sensor tracking
    this.deviceTracking.startAccelerometer(50); // Faster updates for SLAM
    this.deviceTracking.startGyroscope(50);
    this.deviceTracking.startDeviceMotion(50);
    this.deviceTracking.startMagnetometer(50);
  }

  async processFrame(imageData: ImageData): Promise<void> {
    // Extract features from the current frame
    const features = await this.detectFeatures(imageData);
    
    // Update device pose
    const currentPose = this.updatePose();
    
    // Track features and update map
    await this.trackFeaturesAndUpdateMap(features, currentPose);
  }

  private async detectFeatures(imageData: ImageData): Promise<Feature[]> {
    // Implement feature detection (e.g., FAST corner detection)
    // This is a placeholder implementation
    return [];
  }

  private updatePose(): { position: SensorData; orientation: SensorData } {
    const accel = this.deviceTracking.accelerometerData;
    const gyro = this.deviceTracking.gyroscopeData;
    const motion = this.deviceTracking.deviceMotionData;

    // Implement sensor fusion for accurate pose estimation
    // This is a placeholder implementation
    return {
      position: accel || { x: 0, y: 0, z: 0 },
      orientation: gyro || { x: 0, y: 0, z: 0 }
    };
  }

  private async trackFeaturesAndUpdateMap(features: Feature[], currentPose: any): Promise<void> {
    // Match features with existing map points
    for (const feature of features) {
      const matchedPoint = this.findMatchingMapPoint(feature);
      if (matchedPoint) {
        // Update existing map point
        this.updateMapPoint(matchedPoint, feature, currentPose);
      } else {
        // Create new map point
        this.createMapPoint(feature, currentPose);
      }
    }

    // Update feature tracking status
    this.updateFeatureTrackingStatus();
  }

  private findMatchingMapPoint(feature: Feature): MapPoint | null {
    // Implement feature matching logic
    // This is a placeholder implementation
    return null;
  }

  private updateMapPoint(mapPoint: MapPoint, feature: Feature, pose: any): void {
    mapPoint.observations.push(feature);
    // Update position based on new observation
    this.updateMapPointPosition(mapPoint);
  }

  private createMapPoint(feature: Feature, pose: any): void {
    const mapPoint: MapPoint = {
      id: `map-point-${Date.now()}`,
      position: feature.position,
      observations: [feature],
      confidence: 1
    };
    this.mapPoints.set(mapPoint.id, mapPoint);
  }

  private updateMapPointPosition(mapPoint: MapPoint): void {
    // Implement triangulation or optimization to update map point position
    // This is a placeholder implementation
  }

  private updateFeatureTrackingStatus(): void {
    const currentTime = Date.now();
    // Remove features that haven't been seen recently
    for (const [id, feature] of this.features) {
      if (currentTime - feature.lastSeen > 5000) { // 5 seconds timeout
        this.features.delete(id);
      }
    }
  }

  public getMapPoints(): MapPoint[] {
    return Array.from(this.mapPoints.values());
  }

  public getCurrentPose(): { position: SensorData; orientation: SensorData } | null {
    return this.lastPose;
  }

  public cleanup(): void {
    this.deviceTracking.stopAllSensors();
    this.features.clear();
    this.mapPoints.clear();
  }
}