/tracking.js

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<!doctype html>
<html>
<head>
<title>tracking.js - bounding box with camera</title>
<meta charset="utf-8">
<link rel="stylesheet" href="assets/demo.css">
<script src="../build/tracking-min.js"></script>
<script src="../node_modules/dat.gui/build/dat.gui.min.js"></script>
<script src="assets/stats.min.js"></script>
<style>
#boundingBox {
display: none;
position: absolute;
background: white;
border: 1px dashed;
opacity: .5;
z-index: 1;
}
#video {
position: absolute;
top: -1000px;
cursor: crosshair;
}
body {
-webkit-touch-callout: none;
-webkit-user-select: none;
-khtml-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
user-select: none;
}
</style>
</head>
<body>
<div class="demo-title">
<p><a href="http://trackingjs.com" target="_parent">tracking.js</a> － Click and drag to select the area to be tracked</p>
</div>
<div id="boundingBox"></div>
<div class="demo-frame">
<div class="demo-container">
<video id="video" width="393" height="295" preload autoplay loop muted controls></video>
<canvas id="canvas" width="800" height="530"></canvas>
</div>
</div>
<script>
(function() {
// BoundingBoxTracker ======================================================
var BoundingBoxTracker = function() {
BoundingBoxTracker.base(this, 'constructor');
};
tracking.inherits(BoundingBoxTracker, tracking.Tracker);
BoundingBoxTracker.prototype.templateDescriptors_ = null;
BoundingBoxTracker.prototype.templateKeypoints_ = null;
BoundingBoxTracker.prototype.fastThreshold = 60;
BoundingBoxTracker.prototype.blur = 3;
BoundingBoxTracker.prototype.setTemplate = function(pixels, width, height) {
var blur = tracking.Image.blur(pixels, width, height, 3);
var grayscale = tracking.Image.grayscale(blur, width, height);
this.templateKeypoints_ = tracking.Fast.findCorners(grayscale, width, height);
this.templateDescriptors_ = tracking.Brief.getDescriptors(grayscale, width, this.templateKeypoints_);
};
BoundingBoxTracker.prototype.track = function(pixels, width, height) {
var blur = tracking.Image.blur(pixels, width, height, this.blur);
var grayscale = tracking.Image.grayscale(blur, width, height);
var keypoints = tracking.Fast.findCorners(grayscale, width, height, this.fastThreshold);
var descriptors = tracking.Brief.getDescriptors(grayscale, width, keypoints);
this.emit('track', {
data: tracking.Brief.reciprocalMatch(this.templateKeypoints_, this.templateDescriptors_, keypoints, descriptors)
});
};
// Track ===================================================================
var boundingBox = document.getElementById('boundingBox');
var boxLeft = 403;
var video = document.getElementById('video');
var canvas = document.getElementById('canvas');
var canvasRect = canvas.getBoundingClientRect();
var context = canvas.getContext('2d');
var templateImageData;
var capturing = false;
var videoHeight = 295;
var videoWidth = 393;
var tracker = new BoundingBoxTracker();
tracker.on('track', function(event) {
stats.end();
if (capturing) {
return;
}
// Sorts best matches by confidence.
event.data.sort(function(a, b) {
return b.confidence - a.confidence;
});
// Re-draws template on canvas.
context.putImageData(templateImageData, boxLeft, 0);
// Plots lines connecting matches.
for (var i = 0; i < Math.min(10, event.data.length); i++) {
var template = event.data[i].keypoint1;
var frame = event.data[i].keypoint2;
context.beginPath();
context.strokeStyle = 'magenta';
context.moveTo(frame[0], frame[1]);
context.lineTo(boxLeft + template[0], template[1]);
context.stroke();
}
});
var trackerTask = tracking.track(video, tracker, { camera: true });
// Waits for the user to accept the camera.
trackerTask.stop();
// Sync video ============================================================
function requestFrame() {
window.requestAnimationFrame(function() {
context.clearRect(0, 0, canvas.width, canvas.height);
if (video.readyState === video.HAVE_ENOUGH_DATA) {
try {
context.drawImage(video, 0, 0, videoWidth, videoHeight);
} catch (err) {}
}
requestFrame();
});
}
requestFrame();
// Bounding box drag =====================================================
var initialPoint;
var left;
var top;
var width;
var height;
canvas.addEventListener('mousedown', function(event) {
initialPoint = [event.pageX, event.pageY];
capturing = true;
});
canvas.addEventListener('mousemove', function(event) {
if (capturing) {
left = Math.min(initialPoint[0], event.pageX);
top = Math.min(initialPoint[1], event.pageY);
width = Math.max(initialPoint[0], event.pageX) - left;
height = Math.max(initialPoint[1], event.pageY) - top;
boundingBox.style.display = 'block';
boundingBox.style.left = left + 'px';
boundingBox.style.top = top + 'px';
boundingBox.style.width = width + 'px';
boundingBox.style.height = height + 'px';
}
});
document.addEventListener('mouseup', function() {
boundingBox.style.display = 'none';
setTackerTemplate(left, top, width, height);
capturing = false;
});
function setTackerTemplate(left, top, width, height) {
templateImageData = context.getImageData(left - canvasRect.left, top - canvasRect.top, width, height);
canvas.width = boxLeft + width;
context.putImageData(templateImageData, boxLeft, 0);
trackerTask.stop();
tracker.setTemplate(templateImageData.data, width, height);
trackerTask.run();
}
// GUI Controllers
var gui = new dat.GUI();
gui.add(tracker, 'fastThreshold', 20, 100).step(5);
gui.add(tracker, 'blur', 1.1, 5.0).step(0.1);
}());
</script>
</body>
</html>