如何在react native expo中使用可教机器模型

npm install -g expo-cli

expo init myProject

cd myProject
npm install @tensorflow/tfjs @tensorflow-models/coco-ssd expo-gl expo-gl-cpp expo-camera

import React, { useEffect, useState } from 'react';
import { Text, View, StyleSheet } from 'react-native';
import { Camera } from 'expo-camera';
import { GLView } from 'expo-gl';
import * as tf from '@tensorflow/tfjs';
import '@tensorflow/tfjs-react-native';
import { cameraWithTensors } from '@tensorflow/tfjs-react-native';
import { fetch, decodeJpeg } from '@tensorflow/tfjs-react-native';
import * as cocoSsd from '@tensorflow-models/coco-ssd';

const TensorCamera = cameraWithTensors(Camera);

const ObjectDetection = () => {
  const [model, setModel] = useState(null);
  const [predictions, setPredictions] = useState([]);

  useEffect(() => {
    const loadModel = async () => {
      await tf.ready();
      const model = await cocoSsd.load();
      setModel(model);
    };

    loadModel();
  }, []);

  const handleCameraStream = (images, updatePreview, gl) => {
    const loop = async () => {
      const nextImageTensor = images.next().value;
      const predictions = await model.detect(nextImageTensor);
      setPredictions(predictions);
      tf.dispose(nextImageTensor);
      requestAnimationFrame(loop);
    };

    loop();
  };

  return (
    <View style={styles.container}>
      <TensorCamera
        style={styles.camera}
        type={Camera.Constants.Type.back}
        cameraTextureHeight={1200}
        cameraTextureWidth={1600}
        resizeHeight={200}
        resizeWidth={267}
        resizeDepth={3}
        onReady={handleCameraStream}
        autorender={true}
      />
      <View style={styles.predictionsContainer}>
        {predictions.map((prediction, index) => (
          <Text key={index} style={styles.text}>
            {prediction.class} {Math.round(prediction.score * 100)}%
          </Text>
        ))}
      </View>
    </View>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
  },
  camera: {
    width: 267,
    height: 200,
  },
  predictionsContainer: {
    position: 'absolute',
    bottom: 10,
    left: 10,
    right: 10,
    backgroundColor: 'rgba(0, 0, 0, 0.5)',
    padding: 10,
    maxHeight: 200,
    overflow: 'scroll',
  },
  text: {
    color: '#fff',
    fontSize: 16,
    marginBottom: 5,
  },
});

export default ObjectDetection;

import React from 'react';
import { View } from 'react-native';
import ObjectDetection from './ObjectDetection';

const App = () => {
  return (
    <View style={{ flex: 1 }}>
      <ObjectDetection />
    </View>
  );
};

export default App;

expo start