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Creating Real-Time Virtual Backgrounds With BodyPix and Webcam in HTML and JavaScript
by Miroslav PejicNovember 2nd, 2023
Too Long; Didn't Read
This HTML and JavaScript code creates a virtual background effect for a webcam feed on a web page.
This HTML and JavaScript code creates a virtual background effect for a webcam feed on a web page. It utilizes the BodyPix library to segment the person from the background in real-time and replace the background with an image.
Users can start and stop the virtual background effect with buttons. The code is designed for responsive design, and it allows users to choose between MobileNetV1 and ResNet50 segmentation models. It's a fun and interactive way to enhance video calls with a virtual background
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Virtual Background</title>
<style>
/* Add CSS styles for responsive design */
body {
margin: 0;
padding: 0;
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
height: 100vh;
background-color: #f0f0f0;
}
#videoContainer {
width: 100%;
max-width: 600px; /* Adjust the maximum width as needed */
position: relative;
}
video, canvas {
width: 100%;
height: auto;
border-radius: 1rem;
}
img {
max-width: 100%;
height: auto;
}
button {
margin: 10px;
padding: 10px 20px;
font-size: 18px;
border-radius: 1rem;
border: none;
cursor: pointer;
background-color: #e3e3e3;
}
button:hover {
background-color: #1D2026;
color: #FFF;
}
#errorText {
width: 50%;
color: red;
font-weight: bold;
}
</style>
<!-- Include the BodyPix library -->
<script src="https://cdn.jsdelivr.net/npm/@tensorflow/tfjs/dist/tf.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/@tensorflow-models/body-pix/dist/body-pix.min.js"></script>
</head>
<body>
<!-- https://shubhampandey.in/removing-background-in-realtime/ -->
<p id="errorText"></p>
<!-- Create a container for the video and canvas elements -->
<div id="videoContainer">
<!-- Create a video element for the webcam feed -->
<video id="videoElement" playsinline></video>
<!-- Create a canvas element for the background -->
<canvas id="backgroundCanvas" playsinline hidden></canvas>
</div>
<!-- Example of adding a background image (replace the img src attribute with your image file) -->
<img id="yourBackgroundImage" src="https://i.postimg.cc/t9PJw5P7/forest.jpg" style="display: none;">
<!-- Add buttons for user interaction -->
<button id="startButton">Start Virtual Background</button>
<button id="stopButton" style="display: none;">Stop Virtual Background</button>
<script>
// Initialize variables
let isVirtual = false;
// DOM elements
const videoContainer = document.getElementById('videoContainer');
const videoElement = document.getElementById('videoElement');
const canvasElement = document.getElementById('backgroundCanvas');
const backgroundImage = document.getElementById('yourBackgroundImage');
const ctx = canvasElement.getContext('2d');
const startButton = document.getElementById('startButton');
const stopButton = document.getElementById('stopButton');
const errorText = document.getElementById('errorText');
// MobileNetV1 or ResNet50
const BodyPixModel = 'MobileNetV1';
async function startWebCamStream() {
try {
// Start the webcam stream
const stream = await navigator.mediaDevices.getUserMedia({ video: true });
videoElement.srcObject = stream;
// Wait for the video to play
await videoElement.play();
} catch (error) {
displayError(error)
}
}
// Function to start the virtual background
async function startVirtualBackground() {
try {
// Set canvas dimensions to match video dimensions
canvasElement.width = videoElement.videoWidth;
canvasElement.height = videoElement.videoHeight;
// Load the BodyPix model:
let net = null;
switch (BodyPixModel) {
case 'MobileNetV1':
/*
This is a lightweight architecture that is suitable for real-time applications and has lower computational requirements.
It provides good performance for most use cases.
*/
net = await bodyPix.load({
architecture: 'MobileNetV1',
outputStride: 16, // Output stride (16 or 32). 16 is faster, 32 is more accurate.
multiplier: 0.75, // The model's depth multiplier. Options: 0.50, 0.75, or 1.0.
quantBytes: 2, // The number of bytes to use for quantization (4 or 2).
});
break;
case 'ResNet50':
/*
This is a deeper and more accurate architecture compared to MobileNetV1.
It may provide better segmentation accuracy, but it requires more computational resources and can be slower.
*/
net = await bodyPix.load({
architecture: 'ResNet50',
outputStride: 16, // Output stride (16 or 32). 16 is faster, 32 is more accurate.
quantBytes: 4, // The number of bytes to use for quantization (4 or 2).
});
break;
default:
break;
}
// Start the virtual background loop
isVirtual = true;
videoElement.hidden = true;
canvasElement.hidden = false;
display(canvasElement, 'block');
// Show the stop button and hide the start button
startButton.style.display = 'none';
stopButton.style.display = 'block';
async function updateCanvas() {
if (isVirtual) {
// 1. Segmentation Calculation
const segmentation = await net.segmentPerson(videoElement, {
flipHorizontal: false, // Whether to flip the input video horizontally
internalResolution: 'medium', // The resolution for internal processing (options: 'low', 'medium', 'high')
segmentationThreshold: 0.7, // Segmentation confidence threshold (0.0 - 1.0)
maxDetections: 10, // Maximum number of detections to return
scoreThreshold: 0.2, // Confidence score threshold for detections (0.0 - 1.0)
nmsRadius: 20, // Non-Maximum Suppression (NMS) radius for de-duplication
minKeypointScore: 0.3, // Minimum keypoint detection score (0.0 - 1.0)
refineSteps: 10, // Number of refinement steps for segmentation
});
// 2. Creating a Background Mask
const background = { r: 0, g: 0, b: 0, a: 0 };
const mask = bodyPix.toMask(segmentation, background, { r: 0, g: 0, b: 0, a: 255 });
if (mask) {
ctx.putImageData(mask, 0, 0);
ctx.globalCompositeOperation = 'source-in';
// 3. Drawing the Background
if (backgroundImage.complete) {
ctx.drawImage(backgroundImage, 0, 0, canvasElement.width, canvasElement.height);
} else {
// If the image is not loaded yet, wait for it to load and then draw
backgroundImage.onload = () => {
ctx.drawImage(backgroundImage, 0, 0, canvasElement.width, canvasElement.height);
};
}
// Draw the mask (segmentation)
ctx.globalCompositeOperation = 'destination-over';
ctx.drawImage(videoElement, 0, 0, canvasElement.width, canvasElement.height);
ctx.globalCompositeOperation = 'source-over';
// Add a delay to control the frame rate (adjust as needed) less CPU intensive
// await new Promise((resolve) => setTimeout(resolve, 100));
// Continue updating the canvas
requestAnimationFrame(updateCanvas);
}
}
}
// Start update canvas
updateCanvas();
} catch (error) {
stopVirtualBackground();
displayError(error);
}
}
// Function to stop the virtual background
function stopVirtualBackground() {
isVirtual = false;
videoElement.hidden = false;
canvasElement.hidden = true;
display(canvasElement, 'none');
// Hide the stop button and show the start button
startButton.style.display = 'block';
stopButton.style.display = 'none';
}
// Helper function to set the display style of an element
function display(element, style) {
element.style.display = style;
}
// Helper function to display errors
function displayError(error){
console.error(error);
// Display error message in the <p> element
errorText.textContent = 'An error occurred: ' + error.message;
}
// Add click event listeners to the buttons
startButton.addEventListener('click', startVirtualBackground);
stopButton.addEventListener('click', stopVirtualBackground);
// Start video stream
startWebCamStream();
</script>
</body>
</html>
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