Head tracking using Tracking.Js - this example is linked into a synth made in tone.js - for more details see https://www.piandmash.com/experiments/head-tracking-synth/

headTracking.js

window.onload = function () {
var video = document.getElementById('video');
var canvas = document.getElementById('canvas');
var context = canvas.getContext('2d');
var tracker = new tracking.ObjectTracker('face');
try{
      tracker.setInitialScale(4);
      tracker.setStepSize(2);
      tracker.setEdgesDensity(0.1);

      tracking.track('#video', tracker, { camera: true });
      $("imgSad").hide();
  }
	catch(err) {
  }

tracker.on('track', function(event) {
          context.clearRect(0, 0, canvas.width, canvas.height);
  
          //I am running a counter for the specified use of this script, remove or alter accordingly
          counter += 1;
          console.log(counter);
          if (counter > 75) {
              //specific code to trigger a connected synth script - change for your use
              synth.triggerRelease();
          }

          event.data.forEach(function (rect) {

          context.strokeStyle = '#a64ceb';
          context.strokeRect(rect.x, rect.y, rect.width, rect.height);
          context.font = '11px Helvetica';
          context.fillStyle = "#fff";
          context.fillText('x: ' + rect.x + 'px', rect.x + rect.width + 5, rect.y + 11);
          context.fillText('y: ' + rect.y + 'px', rect.x + rect.width + 5, rect.y + 22);

          if (playing) {
              var averageX = rect.x + (rect.width / 2);
              var averageY = rect.y + (rect.height / 2);

              var xposPercentage = (100 / video.videoWidth) * averageX;
              var yposPercentage = (100 / video.videoHeight) * averageY;

              var valX = parseInt(((synthNotes.length) / 100) * xposPercentage);
              var valY = ((2 - 0) / 100) * yposPercentage;

              //specific code to trigger a connected synth script - change for your use
              synth.triggerAttack(synthNotes[valX]);
              synth.vibratoAmount.value = valY;
              //specific code to trigger a connected synth script - change for your use
          }
          counter = 0;
        });
      });

    };