faceDetection.js

const cv   = require('opencv4nodejs');
const gm   = require('gm');
const path = require('path');
const fs   = require('fs-extra');

if (process.argv.length < 3) {
    return console.log(`Usage:
    node face_detection.js <path_to_image>`);
}

async function main() {
    const imagePath  = process.argv[2];
    const isExist    = await fs.exists(imagePath);

    if (!isExist) return console.error(`Image in path ${imagePath} does not exist.`);;
      
    // detect faces
    const image      = cv.imread(imagePath);
    const classifier = new cv.CascadeClassifier(cv.HAAR_FRONTALFACE_ALT2);
    const { objects, numDetections } = classifier.detectMultiScale(image.bgrToGray());
    console.log('faceRects:', objects);
    console.log('confidences:', numDetections);
    
    if (!objects.length) {
        return new Error('No faces detected!');
    }
    
    blur(imagePath, objects);
}

function blur(imagePath, faceDetails) {
    const extension = path.extname(imagePath);
    const name      = path.basename(imagePath, extension);
    let img         = gm(imagePath);

    img.size(function(err, value){
        if (err) {
            console.log(err);
        } else {
            faceDetails.forEach((faceDetail) => {
                const box    = faceDetail,
                    width  = box.width,
                    height = box.height,
                    left   = box.x,
                    top    = box.y;

                img.region(width, height, left, top).blur(25, 45);
            });

            img.write(__dirname + `/archive/${name}_blured${extension}`, function (err) {
                if (!err) {
                    console.log('done Wrting .....');

                }else{
                    console.error(err);
                }
            });
        }
    });
};

main();