opencv 支持编译多个平台，其中还支持JavaScript，不过编译需要emscripten

编译环境：centos7，Python2.7

1.下载OpenCV源码
官网：https://opencv.org/releases/

例如下载4.8.0版本：
https://github.com/opencv/opencv/archive/4.8.0.zip

2.利用镜像 trzeci/emscripten 构建

#解压OpenCV
unzip opencv-4.8.0.zip
#进入opencv-4.8.0
cd opencv-4.8.0
#拉最新的trzeci/emscripten
docker pull trzeci/emscripten
#开始编译
docker run --rm --workdir /code -v “$PWD”:/code “trzeci/emscripten” python ./platforms/js/build_js.py buildjs

最后编译结果都放在buildjs，其中opencv.js 在 buildjs/bin 下面，拷贝出来就可以用了
当然，也可以直接线上已经编译好的：
https://docs.opencv.org/4.8.0/opencv.js

附上 nodejs 示例

const { Canvas, createCanvas, Image, ImageData, loadImage } = require('canvas');
const { JSDOM } = require('jsdom');
const { writeFileSync, existsSync, mkdirSync } = require('fs');
(async () => {await loadOpenCV();await detect('../out/imgs/lena.jpg')
})();const detect = async(imgPath) => {console.time(imgPath)const image = await loadImage(imgPath);const src = cv.imread(image);let gray = new cv.Mat();cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY, 0);let faces = new cv.RectVector();let eyes = new cv.RectVector();let faceCascade = new cv.CascadeClassifier();let eyeCascade = new cv.CascadeClassifier();// Load pre-trained classifier files. Notice how we reference local files using relative paths just// like we normally would dofaceCascade.load('./models/haarcascade_frontalface_alt2.xml');eyeCascade.load('./models/haarcascade_eye.xml');let mSize = new cv.Size(100, 100);faceCascade.detectMultiScale(gray, faces, 1.11, 6, 0, mSize);console.timeEnd(imgPath)console.log('face size: ',faces.size())for(let i=0;i<faces.size();i++) {console.log(faces.get(i))}for (let i = 0; i < faces.size(); ++i) {let roiGray = gray.roi(faces.get(i));let roiSrc = src.roi(faces.get(i));let point1 = new cv.Point(faces.get(i).x, faces.get(i).y);let point2 = new cv.Point(faces.get(i).x + faces.get(i).width, faces.get(i).y + faces.get(i).height);cv.rectangle(src, point1, point2, [255, 0, 0, 255]);eyeCascade.detectMultiScale(roiGray, eyes);console.log(eyes.size(),'eyes')for (let j = 0; j < eyes.size(); ++j) {let point1 = new cv.Point(eyes.get(j).x, eyes.get(j).y);let point2 = new cv.Point(eyes.get(j).x + eyes.get(j).width, eyes.get(j).y + eyes.get(j).height);cv.rectangle(roiSrc, point1, point2, [0, 0, 255, 255]);}roiGray.delete();roiSrc.delete();}const canvas = createCanvas(image.width, image.height);cv.imshow(canvas, src);writeFileSync(imgPath+'-output.jpg', canvas.toBuffer('image/jpeg'));src.delete(); gray.delete(); faceCascade.delete(); eyeCascade.delete(); faces.delete(); eyes.delete()
}/*** Loads opencv.js.** Installs HTML Canvas emulation to support `cv.imread()` and `cv.imshow`** Mounts given local folder `localRootDir` in emscripten filesystem folder `rootDir`. By default it will mount the local current directory in emscripten `/work` directory. This means that `/work/foo.txt` will be resolved to the local file `./foo.txt`* @param {string} rootDir The directory in emscripten filesystem in which the local filesystem will be mount.* @param {string} localRootDir The local directory to mount in emscripten filesystem.* @returns {Promise} resolved when the library is ready to use.*/
function loadOpenCV (rootDir = './work', localRootDir = process.cwd()) {if (global.Module && global.Module.onRuntimeInitialized && global.cv && global.cv.imread) {return Promise.resolve()}return new Promise(resolve => {installDOM()global.Module = {onRuntimeInitialized () {// We change emscripten current work directory to 'rootDir' so relative paths are resolved// relative to the current local folder, as expectedcv.FS.chdir(rootDir)resolve()},preRun () {// preRun() is another callback like onRuntimeInitialized() but is called just before the// library code runs. Here we mount a local folder in emscripten filesystem and we want to// do this before the library is executed so the filesystem is accessible from the startconst FS = global.Module.FS// create rootDir if it doesn't existsif (!FS.analyzePath(rootDir).exists) {FS.mkdir(rootDir);}// create localRootFolder if it doesn't existsif (!existsSync(localRootDir)) {mkdirSync(localRootDir, { recursive: true });}// FS.mount() is similar to Linux/POSIX mount operation. It basically mounts an external// filesystem with given format, in given current filesystem directory.FS.mount(FS.filesystems.NODEFS, { root: localRootDir }, rootDir);}};global.cv = require('./opencv.js')});
}
function installDOM () {const dom = new JSDOM();global.document = dom.window.document;global.Image = Image;global.HTMLCanvasElement = Canvas;global.ImageData = ImageData;global.HTMLImageElement = Image;
}