如何使用facemesh.js (tensorflow)让控制台记录特定的关键点，也就是鼻子？

<script src="https://cdn.jsdelivr.net/npm/@tensorflow/tfjs@1.8.0/dist/tf.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/@tensorflow-models/facemesh@0.14.0/dist/facemesh.min.js"></script>

<canvas id="canvas"></canvas>

// 获取视频流
const video = document.getElementById('video');

// 加载facemesh模型
let model;
async function loadFacemeshModel() {
  model = await facemesh.load();
}

// 检测关键点并记录特定的关键点
async function detectFacialLandmarks() {
  const predictions = await model.estimateFaces(video);
  if (predictions.length > 0) {
    const nose = predictions[0].annotations.noseTip;
    console.log('鼻子关键点坐标：', nose);
  }
}

// 启动摄像头并进行关键点检测
async function startCamera() {
  const stream = await navigator.mediaDevices.getUserMedia({ video: true });
  video.srcObject = stream;
  video.onloadedmetadata = () => {
    video.play();
    detectFacialLandmarks();
  };
}

// 初始化
async function init() {
  await loadFacemeshModel();
  startCamera();
}

init();