Revision history [back]

let me try to guide you finding your own answer by experiment.

you can try the code below online OpenCV.js Tutorials

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  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();

try to change faceCascade.detectMultiScale parameters like given examples below

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);

i am sure you will find your own answer

let me try to guide you finding your own answer by experiment.

you can try the code below online OpenCV.js Tutorials (just copy and paste it on the page)

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  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();

try to change faceCascade.detectMultiScale parameters like given examples below

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);

i am sure you will find your own answer

let me try to guide you finding your own answer by experiment.

you can try the code below online OpenCV.js Tutorials (just copy and paste it on the page)

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();

try to change faceCascade.detectMultiScale parameters like given examples below

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);

i am sure you will find your own answer