vue2+tracking实现PC端的人脸识别示例

<template>
  <div>
    <div>
      <p>请将摄像头对准患者脸部</p>
      <video id="video" style="transform:rotateY(180deg)" autoplay></video>
    </div>
    <div>
      <p>检测人脸结果</p>
      <canvas id="canvas" width="200" height="200" style="transform:rotateY(180deg)"></canvas>
    </div>
  </div>
</template>

<script>
import { userMedia } from '../utils/utils'
require('tracking/build/tracking-min.js')
require('tracking/build/data/face-min.js')

export default {
  data () {
    return {
      videoObj: null,
      trackerTask: null
    }
  },

  mounted () {
    this.openCamera()
  },

  methods: {
    openCamera () {
      // 有可能触发一些其他的按钮会重新获取
      this.$nextTick(() => {
        const canvas = document.getElementById('canvas')
        const context = canvas.getContext('2d')
        this.videoObj = document.getElementById('video')
        // eslint-disable-next-line no-undef
        const tracker = new tracking.ObjectTracker('face') // 检测人脸
        tracker.setInitialScale(4)
        tracker.setStepSize(2)
        tracker.setEdgesDensity(0.1)

        // eslint-disable-next-line no-undef
        this.trackerTask = tracking.track('#video', tracker, { camera: true })

        const constraints = {
          video: { width: 200, height: 200 },
          audio: false
        }

        userMedia(constraints, this.success, this.error)

        tracker.on('track', (event) => {
          event.data.forEach((rect) => {
            // 绘制到 canvas
            context.drawImage(this.videoObj, 0, 0, canvas.width, canvas.height)
            context.font = '16px Helvetica'
            context.strokeStyle = '#1890ff'
            context.strokeRect(rect.x, rect.y, rect.width, rect.height)
          })

          if (event.data.length !== 0) {
            // 说明检测到人脸了，此时就可以截取图片传递给后端
            // canvas 调用 toDataURL
          }
        })
      })
    },

    handleCancel () {
      this.videoObj.srcObject.getTracks()[0].stop()
      this.trackerTask.stop()
    },

    // 成功显示
    success (stream) {
      this.videoObj.srcObject = stream
      this.videoObj.play()
    },
    // 失败抛出错误，可能用户电脑没有摄像头，或者摄像头权限没有打开
    error (error) {
      // 可以在这里面提示用户
      console.log(`访问用户媒体设备失败${error.name}, ${error.message}`)
    }
  },
  beforeDestroy () {
    this.handleCancel()
  }
}
</script>

export let userMedia = function (constraints, success, error) {
  if (navigator.mediaDevices.getUserMedia) {
    userMedia = function (constraints, success, error) {
      navigator.mediaDevices.getUserMedia(constraints).then(success).catch(error)
    }
  } else if (navigator.webkitGetUserMedia) {
    userMedia = function (constraints, success, error) {
      navigator.webkitGetUserMedia(constraints, success, error)
    }
  } else if (navigator.mozGetUserMedia) {
    userMedia = function (constraints, success, error) {
      navigator.mozGetUserMedia(constraints, success, error)
    }
  } else if (navigator.getUserMedia) {
    userMedia = function (constraints, success, error) {
      navigator.getUserMedia(constraints, success, error)
    }
  }

  userMedia(constraints, success, error)
}