按照此thread http://answers.opencv.org/question/198918/opencvjs-unable-to-load-haar-cascades/?answer=198936#post-id-198936:
xml 文件是在使用 load 函数加载之前“预先构建”的。为了实现这一点,它使用了 utils.js 中的 createFileFromUrl 函数。之后我们终于可以从文件加载分类器了。
let classifier = new cv.CascadeClassifier(); // initialize classifier
let utils = new Utils('errorMessage'); //use utils class
let faceCascadeFile = 'haarcascade_frontalface_default.xml'; // path to xml
// use createFileFromUrl to "pre-build" the xml
utils.createFileFromUrl(faceCascadeFile, faceCascadeFile, () => {
classifier.load(faceCascadeFile); // in the callback, load the cascade from file
});
人脸检测其他示例
TRY IT : https://docs.opencv.org/master/d2/d99/tutorial_js_face_detection.html
let src = cv.imread('canvasInput');
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();
// load pre-trained classifiers
faceCascade.load('haarcascade_frontalface_default.xml');
// detect faces
let msize = new cv.Size(0, 0);
// try to change scaleFactor and minNeighbors values
faceCascade.detectMultiScale(gray, faces,1.05,0);
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]);
roiGray.delete(); roiSrc.delete();
}
cv.imshow('canvasOutput', src);
src.delete(); gray.delete(); faceCascade.delete();
faces.delete(); eyes.delete();
尝试改变faceCascade.detectMultiScale
参数如下所示:
faceCascade.detectMultiScale(gray, faces,1.05,0);
faceCascade.detectMultiScale(gray, faces,1.05,1);
faceCascade.detectMultiScale(gray, faces,2,0);
faceCascade.detectMultiScale(gray, faces,2,1);
faceCascade.detectMultiScale(gray, faces,3,0);
faceCascade.detectMultiScale(gray, faces,3,1);
faceCascade.detectMultiScale(gray, faces,4,0);
faceCascade.detectMultiScale(gray, faces,4,1);