当面数超过两个时触发事件

Posted 2023-03-16

【中文标题】当面数超过两个时触发事件

【英文标题】：Fire an event when number of face more than two

【发布时间】：2020-10-11 19:44:37

【问题描述】：

这是我使用 javascript API 进行人脸检测的代码。 当我检测到两个以上的面孔时，我想添加一个条件，然后做一些事情。 我想在 Chrome 浏览器上创建一个扩展，但我不知道如何在我的代码中添加这个条件

const video = document.getElementById("video");
let predictedAges = [];

Promise.all([
  faceapi.nets.tinyFaceDetector.loadFromUri("/models"),
  faceapi.nets.faceLandmark68Net.loadFromUri("/models"),
  faceapi.nets.faceRecognitionNet.loadFromUri("/models"),
  faceapi.nets.faceExpressionNet.loadFromUri("/models"),
  faceapi.nets.ageGenderNet.loadFromUri("/models")
]).then(startVideo);

function startVideo() 
  navigator.getUserMedia(
     video:  ,
    stream => (video.srcObject = stream),
    err => console.error(err)
  );


video.addEventListener("playing", () => 
  const canvas = faceapi.createCanvasFromMedia(video);
  document.body.append(canvas);

  const displaySize =  width: video.width, height: video.height ;
  faceapi.matchDimensions(canvas, displaySize);

  setInterval(async () => 
    const detections = await faceapi
      .detectAllFaces(video, new faceapi.TinyFaceDetectorOptions())
      .withFaceLandmarks()
      .withFaceExpressions()
      .withAgeAndGender();
    const resizedDetections = faceapi.resizeResults(detections, displaySize);

    canvas.getContext("2d").clearRect(0, 0, canvas.width, canvas.height);

    faceapi.draw.drawDetections(canvas, resizedDetections);
    faceapi.draw.drawFaceLandmarks(canvas, resizedDetections);
    faceapi.draw.drawFaceExpressions(canvas, resizedDetections);

    const age = resizedDetections[0].age;
    const interpolatedAge = interpolateAgePredictions(age);
    const bottomRight = 
      x: resizedDetections[0].detection.box.bottomRight.x - 50,
      y: resizedDetections[0].detection.box.bottomRight.y
    ;

    new faceapi.draw.DrawTextField(
      [`$faceapi.utils.round(interpolatedAge, 0) years`],
      bottomRight
    ).draw(canvas);
  , 100);
);

function interpolateAgePredictions(age) 
  predictedAges = [age].concat(predictedAges).slice(0, 30);
  const avgPredictedAge =
    predictedAges.reduce((total, a) => total + a) / predictedAges.length;
  return avgPredictedAge;

【参考方案1】：

为了回答这个问题，我终于通过使用检测对象的属性找到了解决方案

获取我正在使用的识别中检测到的人脸数量

detections.length

问题解决了！！

if(detections.length>=2) 做点什么！！