如何在前端给视频进行去除绿幕并替换背景？-----Vue3！！

最近在做这个这项目奇店桶装水小程序V1.3.9安装包+骑手端V2.0.1+小程序前端

最近，我在进行前端开发时，遇到了一个难题“如何给前端的视频进行去除绿幕并替换背景”。这是一个“数字人项目”所需，我一直在冥思苦想。终于有了一个解决方法——使用Canvas来处理。

这是真材实料的文章——让你的Canvas的技术更上一层楼！！！

效果图

实现思路

1. 准备工作视频和画布元素：在HTML模板中定义了一个<video>标签用于播放视频，以及一个<canvas>标签用来绘制处理后的视频帧。初始化：在组件挂载(mounted)时，获取视频和画布元素，并初始化绘图上下文。

<template><div class="videoBgRemove"><!-- 视频元素 --><video ref="video" loop autoplay muted style="width: 240px;"><source src="/8_1736396574.mp4" type="video/mp4">Your browser does not support the video tag.</video><!-- 画布元素 --><canvas ref="canvas" width="200" height="450"></canvas></div>
</template><script>
export default {data() {return {featherStrength: 0.4, // 羽化强度控制};},mounted() {// 初始化视频和画布引用this.video = this.$refs.video;this.canvas = this.$refs.canvas;this.ctx = this.canvas.getContext('2d');this.canvas_tmp = document.createElement('canvas');this.canvas_tmp.width = this.canvas.width;this.canvas_tmp.height = this.canvas.height;this.ctx_tmp = this.canvas_tmp.getContext('2d');// 初始化其他变量this.init();},methods: {init() {// 当视频开始播放时，调用computeFrame进行逐帧处理this.video.addEventListener('play', this.computeFrame);}}
};
</script>

2. 视频帧处理逻辑逐帧处理：当视频开始播放时，computeFrame函数会不断被调用，每次调用都会处理一帧视频数据。临时画布：为了不影响原始视频的播放，所有图像处理都在一个临时创建的画布(canvas_tmp)上进行。图像数据获取：从临时画布上获取当前帧的图像数据（像素信息）以进行处理。

javascript">methods: {computeFrame() {if (!this.video || this.video.paused || this.video.ended) return;// 绘制当前帧到临时画布上this.ctx_tmp.drawImage(this.video, 0, 0, this.canvas.width, this.canvas.height);// 获取当前帧的图像数据let frame = this.ctx_tmp.getImageData(0, 0, this.canvas.width, this.canvas.height);// 后续处理...}
}

3. 背景移除颜色检测：假设背景为特定的颜色（例如绿色），对于每个像素点，如果其RGB值符合预设的背景颜色范围，则将其alpha通道设置为0，即变为透明。

javascript">methods: {computeFrame() {// ... (前面的代码)const pointLens = frame.data.length / 4;// 遍历每一个像素点for (let i = 0; i < pointLens; i++) {let r = frame.data[i * 4];let g = frame.data[i * 4 + 1];let b = frame.data[i * 4 + 2];// 假设背景是绿色，将符合条件的像素设置为透明if (r < 100 && g > 120 && b < 200) { frame.data[i * 4 + 3] = 0; // 设置alpha通道为0，使背景透明}}// 后续处理...}
}

4. 羽化效果边缘检测与平均：对于非透明的像素，计算它周围的像素，取周围像素颜色的平均值作为新颜色，并根据周围的透明度调整当前像素的透明度，以此来实现羽化效果。强度控制：通过featherStrength参数可以控制羽化的程度，从而让边缘过渡更加自然。

javascript">methods: {computeFrame() {// ... (前面的代码)// 创建一个临时的数据副本，避免修改原始数据const tempData = [...frame.data];// 对非透明像素应用羽化效果for (let i = 0; i < pointLens; i++) {if (frame.data[i * 4 + 3] === 0) continue; // 忽略已经透明的像素// 计算当前像素的位置let [row, col] = this.numToPoint(i + 1, frame.width);// 获取周围的像素点let aroundPoints = this.getAroundPoint([row, col], frame.width, frame.height, 3);// 计算周围非透明像素的颜色平均值let opNum = 0;let rSum = 0;let gSum = 0;let bSum = 0;aroundPoints.forEach(([pRow, pCol]) => {let index = this.pointToNum([pRow, pCol], frame.width);rSum += tempData[(index - 1) * 4];gSum += tempData[(index - 1) * 4 + 1];bSum += tempData[(index - 1) * 4 + 2];if (tempData[(index - 1) * 4 + 3] !== 255) opNum++;});// 计算新的alpha值let alpha = (255 / aroundPoints.length) * (aroundPoints.length - opNum);// 根据羽化强度调整alphaif (alpha !== 255) {frame.data[i * 4] = parseInt(rSum / aroundPoints.length);frame.data[i * 4 + 1] = parseInt(gSum / aroundPoints.length);frame.data[i * 4 + 2] = parseInt(bSum / aroundPoints.length);frame.data[i * 4 + 3] = parseInt(alpha * this.featherStrength);}}// 将处理后的图像数据绘制到实际显示的画布上this.ctx.putImageData(frame, 0, 0);// 持续循环requestAnimationFrame(this.computeFrame);},numToPoint(num, width) {let col = num % width;let row = Math.floor(num / width);return [row + 1, col === 0 ? width : col];},pointToNum(point, width) {let [row, col] = point;return (row - 1) * width + col;},getAroundPoint(point, width, height, area) {let [row, col] = point;let allAround = [];for (let i = -Math.floor(area / 2); i <= Math.floor(area / 2); i++) {for (let j = -Math.floor(area / 2); j <= Math.floor(area / 2); j++) {if (i === 0 && j === 0) continue; // 跳过中心点let pRow = row + i;let pCol = col + j;if (pRow > 0 && pCol > 0 && pRow <= height && pCol <= width) {allAround.push([pRow, pCol]);}}}return allAround;}
}

5. 显示处理结果更新画布：将处理后的图像数据应用到实际显示的画布(canvas)上，这样用户就能看到带有透明背景和羽化效果的视频了。

javascript">// 将处理后的图像数据绘制到实际显示的画布上
this.ctx.putImageData(frame, 0, 0);

6. 持续循环递归调用：computeFrame函数会在每一帧处理完毕后立即再次调用自己，形成一个持续的循环，直到视频停止播放。代码加在这里面。

javascript">methods: {computeFrame() {// ... (前面的代码)// 持续循环requestAnimationFrame(this.computeFrame);}
}

完整的demo

1.App.vue

javascript"><template><div id="app"><h1>背景人像处理</h1><VideoRemoval /></div>
</template><script>
import VideoRemoval from './components/VideoRemoval.vue';export default {name: 'App',components: {VideoRemoval}
}
</script><style>
#app {font-family: Avenir, Helvetica, Arial, sans-serif;-webkit-font-smoothing: antialiased;-moz-osx-font-smoothing: grayscale;text-align: center;color: #2c3e50;margin-top: 60px;background-image: url("../src/assets/web_bg.jpg"); /* 使用正确的路径 */background-size: cover; /* 背景图片覆盖整个容器 */background-position: center center; /* 背景图片居中显示 */background-repeat: no-repeat; /* 防止背景图片重复 */background-attachment: fixed; /* 背景固定在视口 */
}
</style>

2.VideoRemoval.vue

javascript"><template><div class="videoBgRemove"><video id="video"src="/8_1736396574.mp4"loopautoplaymutedref="video"style="width: 240px;"></video><canvas id="output-canvas"width="200"height="450"willReadFrequently="true"ref="canvas"></canvas></div>
</template><script>
export default {data () {return {video: null,canvas: null,ctx: null,canvas_tmp: null,ctx_tmp: null,featherStrength: 0.4, // 羽化强度控制};},methods: {init () {this.ctx = this.canvas.getContext('2d');this.canvas_tmp = document.createElement('canvas');this.canvas_tmp.setAttribute('width', 200);this.canvas_tmp.setAttribute('height', 450);this.ctx_tmp = this.canvas_tmp.getContext('2d');this.video.addEventListener('play', this.computeFrame);},numToPoint (num, width) {let col = num % width;let row = Math.floor(num / width);row = col === 0 ? row : row + 1;col = col === 0 ? width : col;return [row, col];},pointToNum (point, width) {let [row, col] = point;return (row - 1) * width + col;},getAroundPoint (point, width, height, area) {let [row, col] = point;let allAround = [];if (row > height || col > width || row < 0 || col < 0) return allAround;for (let i = 0; i < area; i++) {let pRow = row - 1 + i;for (let j = 0; j < area; j++) {let pCol = col - 1 + j;if (i === area % 2 && j === area % 2) continue;allAround.push([pRow, pCol]);}}return allAround.filter(([iRow, iCol]) => {return iRow > 0 && iCol > 0 && iRow <= height && iCol <= width;});},computeFrame () {if (this.video) {if (this.video.paused || this.video.ended) return;}this.ctx_tmp.drawImage(this.video, 0, 0, this.video.clientWidth, this.video.clientHeight);let frame = this.ctx_tmp.getImageData(0, 0, this.video.clientWidth, this.video.clientHeight);const height = frame.height;const width = frame.width;const pointLens = frame.data.length / 4;// 背景透明化（假设背景为特定颜色，这里选择绿色）for (let i = 0; i < pointLens; i++) {let r = frame.data[i * 4];let g = frame.data[i * 4 + 1];let b = frame.data[i * 4 + 2];if (r < 100 && g > 120 && b < 200) {frame.data[i * 4 + 3] = 0;}}const tempData = [...frame.data];for (let i = 0; i < pointLens; i++) {if (frame.data[i * 4 + 3] === 0) continue;const currentPoint = this.numToPoint(i + 1, width);const arroundPoint = this.getAroundPoint(currentPoint, width, height, 3);let opNum = 0;let rSum = 0;let gSum = 0;let bSum = 0;arroundPoint.forEach((position) => {const index = this.pointToNum(position, width);rSum += tempData[(index - 1) * 4];gSum += tempData[(index - 1) * 4 + 1];bSum += tempData[(index - 1) * 4 + 2];if (tempData[(index - 1) * 4 + 3] !== 255) opNum++;});let alpha = (255 / arroundPoint.length) * (arroundPoint.length - opNum);// 调整羽化效果if (alpha !== 255) {frame.data[i * 4] = parseInt(rSum / arroundPoint.length);frame.data[i * 4 + 1] = parseInt(gSum / arroundPoint.length);frame.data[i * 4 + 2] = parseInt(bSum / arroundPoint.length);// 根据羽化强度调整 alphaframe.data[i * 4 + 3] = parseInt(alpha * this.featherStrength);}}this.ctx.putImageData(frame, 0, 0);setTimeout(this.computeFrame, 0);}},mounted () {this.video = this.$refs.video;this.canvas = this.$refs.canvas;this.init();}
};
</script>

完整项目demo在前端给视频去除绿幕并替换背景: 最近，我在进行前端开发时，遇到了一个难题“如何给前端的视频进行去除绿幕并替换背景”。这是一个“数字人项目”所需，我一直在冥思苦想。终于有了一个解决方法——使用Canvas来处理。这是真材实料的文章——让你的Canvas的技术更上一层楼！！！