speedy-vision
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GPU-accelerated Computer Vision for JavaScript
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HTML
<!--
speedy-vision.js
GPU-accelerated Computer Vision for JavaScript
Copyright 2020-2022 Alexandre Martins <alemartf(at)gmail.com>
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
best-features.html
Find & select the best features
-->
<html>
<head>
<meta charset="utf-8">
<meta name="description" content="speedy-vision.js: GPU-accelerated Computer Vision for JavaScript">
<meta name="author" content="Alexandre Martins">
<title>Find the best keypoints</title>
<script src="../dist/speedy-vision.js"></script>
<link href="style.css" rel="stylesheet">
</head>
<body>
<h1>Find the best keypoints</h1>
<form autocomplete="off">
<div>
Give me the
<select id="feature-limit">
<option value="50">50</option>
<option value="100">100</option>
<option value="200">200</option>
<option value="300">300</option>
<option value="500">500</option>
<option value="800" selected>800</option>
<option value="1200">1200</option>
<option value="1600">1600</option>
<option value="2000">2000</option>
</select>
best keypoints (corner response function)
</div>
<div class="separator"></div>
<div>
<label for="sensitivity">Sensitivity</label>
<input type="range" min="0.0" max="0.99" value="0.9" step="0.01" id="sensitivity">
</div>
<div>
<label for="speed-slider">Video speed</label>
<input type="range" id="speed-slider" min="0.10" max="2" value="1" step="0.01">
</div>
<div>
<label for="multiscale">Multi-scale</label>
<input type="checkbox" id="multiscale">
</div>
</form>
<div>
<span id="status"></span>
<canvas id="canvas-demo"></canvas>
</div>
<div>
<button id="play">Play / pause</button>
</div>
<video
src="../assets/people.webm"
poster="../assets/loading.jpg"
width="640" height="360"
preload="auto"
loop muted hidden
title="Free to use video by Free Videos, https://www.pexels.com/pt-br/foto/853889/">
</video>
<script>
window.onload = async function()
{
// form elements
const multiscale = document.getElementById('multiscale');
const sensitivity = document.getElementById('sensitivity');
const featureLimit = document.getElementById('feature-limit');
const speedSlider = document.getElementById('speed-slider');
const playButton = document.getElementById('play');
// load the video
const video = document.querySelector('video');
const media = await Speedy.load(video);
video.play();
// create the pipeline
const pipeline = Speedy.Pipeline();
const source = Speedy.Image.Source();
const greyscale = Speedy.Filter.Greyscale();
const pyramid = Speedy.Image.Pyramid();
const detector = Speedy.Keypoint.Detector.Harris();
const clipper = Speedy.Keypoint.Clipper();
const sink = Speedy.Keypoint.Sink();
source.media = media;
detector.capacity = 8192;
source.output().connectTo(greyscale.input());
greyscale.output().connectTo(pyramid.input());
pyramid.output().connectTo(detector.input());
detector.output().connectTo(clipper.input());
clipper.output().connectTo(sink.input());
pipeline.init(source, greyscale, pyramid, detector, clipper, sink);
// Main loop
(function() {
const canvas = createCanvas(media.width, media.height, video.title);
let keypoints = [], frameReady = false;
async function update()
{
detector.levels = multiscale.checked ? 6 : 1; // multiscale?
detector.quality = 1.0 - Number(sensitivity.value); // adjust sensitivity
clipper.size = Number(featureLimit.value); // cap the number of keypoints
const result = await pipeline.run();
keypoints = result.keypoints;
frameReady = true;
setTimeout(update, 1000 / 60);
}
update();
function render()
{
if(frameReady) {
draw(media, canvas);
renderFeatures(canvas, keypoints);
}
frameReady = false;
requestAnimationFrame(render);
}
render();
setInterval(() => renderStatus(keypoints), 200);
})();
// misc
playButton.onclick = () => video.paused ? video.play() : video.pause();
speedSlider.oninput = () => video.playbackRate = speedSlider.value;
}
function createCanvas(width, height, title)
{
const canvas = document.getElementById('canvas-demo') || document.createElement('canvas');
canvas.width = width;
canvas.height = height;
canvas.title = title;
if(!document.body.contains(canvas))
document.body.appendChild(canvas);
return canvas;
}
function renderFeatures(canvas, features, size = 1, color = 'yellow')
{
const context = canvas.getContext('2d');
context.beginPath();
for(let feature of features) {
let radius = size * feature.scale;
// draw scaled circle
context.moveTo(feature.x + radius, feature.y);
context.arc(feature.x, feature.y, radius, 0, Math.PI * 2.0);
// draw rotation line
const sin = Math.sin(feature.rotation);
const cos = Math.cos(feature.rotation);
context.moveTo(feature.x, feature.y);
context.lineTo(feature.x + radius * cos, feature.y + radius * sin);
}
context.strokeStyle = color;
context.stroke();
}
function renderStatus(features)
{
const status = document.getElementById('status');
status.innerText = `FPS: ${Speedy.fps} | Keypoints: ${features.length}`;
}
function draw(media, canvas, x = 0, y = 0, width = media.width, height = media.height)
{
const ctx = canvas.getContext('2d');
ctx.drawImage(media.source, x, y, width, height);
}
</script>
<mark>Powered by <a href="https://github.com/alemart/speedy-vision">speedy-vision.js</a></mark>
</body>
</html>