opencv4nodejs-prebuilt-install - npm Package Compare versions

Comparing version 4.1.131 to 4.1.134

lib/bundle.js

@@ -0,0 +0,0 @@ const { opencvLibDir } = require("./dirs");

lib/commons.js

@@ -0,0 +0,0 @@ const fs = require('fs')

lib/cv.js

@@ -0,0 +0,0 @@ const path = require('path');

lib/dirs.js

@@ -0,0 +0,0 @@ const { join } = require("path");

lib/index.d.ts

@@ -0,0 +0,0 @@ export * from './typings/cv.d';

lib/opencv4nodejs.js

@@ -0,0 +0,0 @@ const promisify = require('./promisify');

lib/promisify.js

@@ -0,0 +0,0 @@ const isFn = obj => typeof obj === 'function';

lib/src/drawUtils.js

@@ -0,0 +0,0 @@ module.exports = function(cv) {

lib/src/index.js

@@ -0,0 +0,0 @@ const makeDrawUtils = require('./drawUtils')

lib/typings/AGASTDetector.d.ts

@@ -0,0 +0,0 @@ import { KeyPointDetector } from './KeyPointDetector.d';

lib/typings/AKAZEDetector.d.ts

@@ -0,0 +0,0 @@ import { FeatureDetector } from './FeatureDetector.d';

lib/typings/BackgroundSubtractorKNN.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/BackgroundSubtractorMOG2.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/BFMatcher.d.ts

@@ -0,0 +0,0 @@ import {Mat} from "./Mat";

lib/typings/BRISKDetector.d.ts

@@ -0,0 +0,0 @@ import { FeatureDetector } from './FeatureDetector';

lib/typings/CascadeClassifier.d.ts

@@ -0,0 +0,0 @@ import { Size } from './Size.d';

lib/typings/config.d.ts

@@ -0,0 +0,0 @@ export const xmodules: {

lib/typings/constants.d.ts

@@ -0,0 +0,0 @@ export const CV_8U: number;

lib/typings/Contour.d.ts

@@ -0,0 +0,0 @@ import { Rect } from './Rect.d';

lib/typings/cv.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/DescriptorMatch.d.ts

@@ -0,0 +0,0 @@ export class DescriptorMatch {

lib/typings/DetectionROI.d.ts

@@ -0,0 +0,0 @@ import { Point2 } from './Point2.d';

lib/typings/EigenFaceRecognizer.d.ts

@@ -0,0 +0,0 @@ import { FaceRecognizer } from './FaceRecognizer';

lib/typings/Facemark.d.ts

@@ -0,0 +0,0 @@ import { Mat } from "./Mat.d";

lib/typings/FacemarkAAMParams.d.ts

@@ -0,0 +0,0 @@ export class FacemarkAAMParams {

lib/typings/FacemarkLBF.d.ts

 import { Facemark } from "./Facemark";
 
 export class FacemarkLBF extends Facemark {}

lib/typings/FacemarkLBFParams.d.ts

@@ -0,0 +0,0 @@ import { Rect } from "./Rect.d";

lib/typings/FacemarkrAAM.d.ts

 import { Facemark } from "./Facemark";
 
 export class FacemarkAAM extends Facemark {}

lib/typings/FaceRecognizer.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat';

lib/typings/FASTDetector.d.ts

@@ -0,0 +0,0 @@ import { KeyPointDetector } from './KeyPointDetector';

lib/typings/FeatureDetector.d.ts

@@ -0,0 +0,0 @@ import { KeyPointDetector } from './KeyPointDetector';

lib/typings/FisherFaceRecognizer.d.ts

@@ -0,0 +0,0 @@ import { FaceRecognizer } from './FaceRecognizer';

lib/typings/GFTTDetector.d.ts

@@ -0,0 +0,0 @@ import { KeyPointDetector } from './KeyPointDetector';

lib/typings/HOGDescriptor.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/KAZEDetector.d.ts

@@ -0,0 +0,0 @@ import { FeatureDetector } from './FeatureDetector.d';

lib/typings/KeyPoint.d.ts

@@ -0,0 +0,0 @@ import { Point2 } from './Point2.d';

lib/typings/KeyPointDetector.d.ts

@@ -0,0 +0,0 @@ import { KeyPoint } from './KeyPoint.d';

lib/typings/LBPHFaceRecognizer.d.ts

@@ -0,0 +0,0 @@ import { FaceRecognizer } from './FaceRecognizer';

lib/typings/Mat.d.ts

@@ -0,0 +0,0 @@ import { Size } from './Size.d';

lib/typings/Moments.d.ts

@@ -0,0 +0,0 @@ export class Moments {

lib/typings/MSERDetector.d.ts

@@ -0,0 +0,0 @@ import { KeyPointDetector } from './KeyPointDetector.d';

lib/typings/MultiTracker.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/Net.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/OCRHMMClassifier.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/OCRHMMDecoder.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/ORBDetector.d.ts

@@ -0,0 +0,0 @@ import { FeatureDetector } from './FeatureDetector.d';

lib/typings/ParamGrid.d.ts

@@ -0,0 +0,0 @@ export class ParamGrid {

lib/typings/Point.d.ts

@@ -0,0 +0,0 @@ export class Point {

lib/typings/Point2.d.ts

@@ -0,0 +0,0 @@ import { Point } from './Point.d';

lib/typings/Point3.d.ts

@@ -0,0 +0,0 @@ import { Point } from './Point';

lib/typings/Rect.d.ts

@@ -0,0 +0,0 @@ import { Size } from './Size.d';

lib/typings/RotatedRect.d.ts

@@ -0,0 +0,0 @@ import { Size } from './Size.d';

lib/typings/SIFTDetector.d.ts

@@ -0,0 +0,0 @@ import { FeatureDetector } from './FeatureDetector.d';

lib/typings/SimpleBlobDetector.d.ts

@@ -0,0 +0,0 @@ import { FeatureDetector } from './FeatureDetector.d';

lib/typings/SimpleBlobDetectorParams.d.ts

@@ -0,0 +0,0 @@ export class SimpleBlobDetectorParams {

lib/typings/Size.d.ts

@@ -0,0 +0,0 @@ export class Size {

lib/typings/SuperpixelLSC.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/SuperpixelSEEDS.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/SuperpixelSLIC.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/SURFDetector.d.ts

@@ -0,0 +0,0 @@ import { FeatureDetector } from './FeatureDetector.d';

lib/typings/SVM.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/TermCriteria.d.ts

@@ -0,0 +0,0 @@ export class TermCriteria {

lib/typings/TrackerBoosting.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/TrackerBoostingParams.d.ts

@@ -0,0 +0,0 @@ export class TrackerBoostingParams {

lib/typings/TrackerCSRT.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/TrackerCSRTParams.d.ts

@@ -0,0 +0,0 @@ export class TrackerKCFParams {

lib/typings/TrackerGOTURN.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/TrackerKCF.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/TrackerKCFParams.d.ts

@@ -0,0 +0,0 @@ export class TrackerKCFParams {

lib/typings/TrackerMedianFlow.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/TrackerMIL.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/TrackerMILParams.d.ts

@@ -0,0 +0,0 @@ export class TrackerMILParams {

lib/typings/TrackerMOSSE.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/TrackerTLD.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/TrainData.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/Vec.d.ts

@@ -0,0 +0,0 @@ import { Vec3 } from './Vec3.d';

lib/typings/Vec2.d.ts

@@ -0,0 +0,0 @@ import { Vec } from './Vec.d';

lib/typings/Vec3.d.ts

@@ -0,0 +0,0 @@ import { Vec } from './Vec.d';

lib/typings/Vec4.d.ts

@@ -0,0 +0,0 @@ import { Vec } from './Vec.d';

lib/typings/Vec6.d.ts

@@ -0,0 +0,0 @@ import { Vec } from './Vec.d';

lib/typings/VideoCapture.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

lib/typings/VideoWriter.d.ts

@@ -0,0 +0,0 @@ import { Mat } from './Mat.d';

package.json

 {
   "name": "opencv4nodejs-prebuilt-install",
-  "version": "4.1.131",
+  "version": "4.1.134",
   "description": "Asynchronous OpenCV 4.x nodejs bindings with JavaScript and TypeScript API.",
@@ -42,3 +42,3 @@ "keywords": [
   "typings": "./lib/index.d.ts",
-  "scripts": {
+  "scripts_publish": {
     "install": "prebuild-install || exit 0"
@@ -45,0 +45,0 @@ },

README.md

 # opencv4nodejs-prebuilt-install
 
-### Simple installation Opencv 4.1.1 for node pre-compiled bindings
+![Tested](https://github.com/udarrr/opencv4nodejs-prebuilt-install/workflows/Tests/badge.svg)
+![Released](https://github.com/udarrr/opencv4nodejs-prebuilt-install/workflows/Create%20tagged%20release/badge.svg)
+![Supported node LTS versions](https://img.shields.io/badge/node@arch64-12%2C%2013%2C%2014%2C%2015%2C%2016%2C%2017%2C%2018%2C%2019-green)
 
+### Simple installation Opencv 4.1.1 for node with pre-compiled bindings
+
 Cross-platform!
@@ -12,1 +16,395 @@
 - arh x64
+
+## How to install
+
+``` bash
+npm i opencv4nodejs-prebuilt-install
+```
+
+- **[Examples](#examples)**
+- **[Quick Start](#quick-start)**
+- **[Async API](#async-api)**
+- **[With TypeScript](#with-typescript)**
+- **[External Memory Tracking (v4.0.0)](#external-mem-tracking)**
+
+## Examples
+
+See [examples](https://github.com/UrielCh/opencv4nodejs/tree/master/examples) for implementation.
+
+### Face Detection
+
+![face0](https://user-images.githubusercontent.com/31125521/29702727-c796acc4-8972-11e7-8043-117dd2761833.jpg)
+![face1](https://user-images.githubusercontent.com/31125521/29702730-c79d3904-8972-11e7-8ccb-e8c467244ad8.jpg)
+
+### Face Recognition with the OpenCV face module
+
+Check out [Node.js + OpenCV for Face Recognition](https://medium.com/@muehler.v/node-js-opencv-for-face-recognition-37fa7cb860e8)</b></a>.
+
+![facerec](https://user-images.githubusercontent.com/31125521/35453007-eac9d516-02c8-11e8-9c4d-a77c01ae1f77.jpg)
+
+### Face Landmarks with the OpenCV face module
+
+![facelandmarks](https://user-images.githubusercontent.com/31125521/39297394-af14ae26-4943-11e8-845a-a06cbfa28d5a.jpg)
+
+### Face Recognition with [face-recognition.js](https://github.com/justadudewhohacks/face-recognition.js)
+
+Check out [Node.js + face-recognition.js : Simple and Robust Face Recognition using Deep Learning](https://medium.com/@muehler.v/node-js-face-recognition-js-simple-and-robust-face-recognition-using-deep-learning-ea5ba8e852).
+
+[![IMAGE ALT TEXT](https://user-images.githubusercontent.com/31125521/35453884-055f3bde-02cc-11e8-8fa6-945f320652c3.jpg)](https://www.youtube.com/watch?v=ArcFHpX-usQ "Nodejs Face Recognition using face-recognition.js and opencv4nodejs")
+
+### Hand Gesture Recognition
+
+Check out [Simple Hand Gesture Recognition using OpenCV and JavaScript](https://medium.com/@muehler.v/simple-hand-gesture-recognition-using-opencv-and-javascript-eb3d6ced28a0).
+
+![gesture-rec_sm](https://user-images.githubusercontent.com/31125521/30052864-41bd5680-9227-11e7-8a62-6205f3d99d5c.gif)
+
+### Object Recognition with Deep Neural Networks
+
+Check out [Node.js meets OpenCV’s Deep Neural Networks — Fun with Tensorflow and Caffe](https://medium.com/@muehler.v/node-js-meets-opencvs-deep-neural-networks-fun-with-tensorflow-and-caffe-ff8d52a0f072).
+
+#### Tensorflow Inception
+
+![husky](https://user-images.githubusercontent.com/31125521/32703295-f6b0e7ee-c7f3-11e7-8039-b3ada21810a0.jpg)
+![car](https://user-images.githubusercontent.com/31125521/32703296-f6cea892-c7f3-11e7-8aaa-9fe48b88fe05.jpeg)
+![banana](https://user-images.githubusercontent.com/31125521/32703297-f6e932ca-c7f3-11e7-9a66-bbc826ebf007.jpg)
+
+#### Single Shot Multibox Detector with COCO
+
+![dishes-detection](https://user-images.githubusercontent.com/31125521/32703228-eae787d4-c7f2-11e7-8323-ea0265deccb3.jpg)
+![car-detection](https://user-images.githubusercontent.com/31125521/32703229-eb081e36-c7f2-11e7-8b26-4d253b4702b4.jpg)
+
+### Machine Learning
+
+Check out [Machine Learning with OpenCV and JavaScript: Recognizing Handwritten Letters using HOG and SVM](https://medium.com/@muehler.v/machine-learning-with-opencv-and-javascript-part-1-recognizing-handwritten-letters-using-hog-and-88719b70efaa).
+
+![resulttable](https://user-images.githubusercontent.com/31125521/30635645-5a466ea8-9df3-11e7-8498-527e1293c4fa.png)
+
+### Object Tracking
+
+![trackbgsubtract](https://user-images.githubusercontent.com/31125521/29702733-c7b59864-8972-11e7-996b-d28cb508f3b8.gif)
+![trackbycolor](https://user-images.githubusercontent.com/31125521/29702735-c8057686-8972-11e7-9c8d-13e30ab74628.gif)
+
+### Feature Matching
+
+![matchsift](https://user-images.githubusercontent.com/31125521/29702731-c79e3142-8972-11e7-947e-db109d415469.jpg)
+
+### Image Histogram
+
+![plotbgr](https://user-images.githubusercontent.com/31125521/29995016-1b847970-8fdf-11e7-9316-4eb0fd550adc.jpg)
+![plotgray](https://user-images.githubusercontent.com/31125521/29995015-1b83e06e-8fdf-11e7-8fa8-5d18326b9cd3.jpg)
+
+### Boiler plate for combination of opencv4nodejs, express and websockets
+
+[opencv4nodejs-express-websockets](https://github.com/Mudassir-23/opencv4nodejs-express-websockets) - Boilerplate express app for getting started on opencv with nodejs and to live stream the video through websockets.
+
+### Automating lights by people detection through classifier
+
+Check out [Automating lights with Computer Vision & NodeJS](https://medium.com/softway-blog/automating-lights-with-computer-vision-nodejs-fb9b614b75b2).
+
+![user-presence](https://user-images.githubusercontent.com/34403479/70385871-8d62e680-19b7-11ea-855c-3b2febfdbd72.png)
+
+## Quick Start
+
+``` javascript
+const cv = require('opencv4nodejs-prebuilt-install');
+```
+
+### Initializing Mat (image matrix), Vec, Point
+
+``` javascript
+const rows = 100; // height
+const cols = 100; // width
+
+// empty Mat
+const emptyMat = new cv.Mat(rows, cols, cv.CV_8UC3);
+
+// fill the Mat with default value
+const whiteMat = new cv.Mat(rows, cols, cv.CV_8UC1, 255);
+const blueMat = new cv.Mat(rows, cols, cv.CV_8UC3, [255, 0, 0]);
+
+// from array (3x3 Matrix, 3 channels)
+const matData = [
+  [[255, 0, 0], [255, 0, 0], [255, 0, 0]],
+  [[0, 0, 0], [0, 0, 0], [0, 0, 0]],
+  [[255, 0, 0], [255, 0, 0], [255, 0, 0]]
+];
+const matFromArray = new cv.Mat(matData, cv.CV_8UC3);
+
+// from node buffer
+const charData = [255, 0, ...];
+const matFromArray = new cv.Mat(Buffer.from(charData), rows, cols, cv.CV_8UC3);
+
+// Point
+const pt2 = new cv.Point(100, 100);
+const pt3 = new cv.Point(100, 100, 0.5);
+
+// Vector
+const vec2 = new cv.Vec(100, 100);
+const vec3 = new cv.Vec(100, 100, 0.5);
+const vec4 = new cv.Vec(100, 100, 0.5, 0.5);
+```
+
+### Mat and Vec operations
+
+``` javascript
+const mat0 = new cv.Mat(...);
+const mat1 = new cv.Mat(...);
+
+// arithmetic operations for Mats and Vecs
+const matMultipliedByScalar = mat0.mul(0.5);  // scalar multiplication
+const matDividedByScalar = mat0.div(2);       // scalar division
+const mat0PlusMat1 = mat0.add(mat1);          // addition
+const mat0MinusMat1 = mat0.sub(mat1);         // subtraction
+const mat0MulMat1 = mat0.hMul(mat1);          // elementwise multiplication
+const mat0DivMat1 = mat0.hDiv(mat1);          // elementwise division
+
+// logical operations Mat only
+const mat0AndMat1 = mat0.and(mat1);
+const mat0OrMat1 = mat0.or(mat1);
+const mat0bwAndMat1 = mat0.bitwiseAnd(mat1);
+const mat0bwOrMat1 = mat0.bitwiseOr(mat1);
+const mat0bwXorMat1 = mat0.bitwiseXor(mat1);
+const mat0bwNot = mat0.bitwiseNot();
+```
+
+### Accessing Mat data
+
+``` javascript
+const matBGR = new cv.Mat(..., cv.CV_8UC3);
+const matGray = new cv.Mat(..., cv.CV_8UC1);
+
+// get pixel value as vector or number value
+const vec3 = matBGR.at(200, 100);
+const grayVal = matGray.at(200, 100);
+
+// get raw pixel value as array
+const [b, g, r] = matBGR.atRaw(200, 100);
+
+// set single pixel values
+matBGR.set(50, 50, [255, 0, 0]);
+matBGR.set(50, 50, new Vec(255, 0, 0));
+matGray.set(50, 50, 255);
+
+// get a 25x25 sub region of the Mat at offset (50, 50)
+const width = 25;
+const height = 25;
+const region = matBGR.getRegion(new cv.Rect(50, 50, width, height));
+
+// get a node buffer with raw Mat data
+const matAsBuffer = matBGR.getData();
+
+// get entire Mat data as JS array
+const matAsArray = matBGR.getDataAsArray();
+```
+
+### IO
+
+``` javascript
+// load image from file
+const mat = cv.imread('./path/img.jpg');
+cv.imreadAsync('./path/img.jpg', (err, mat) => {
+  ...
+})
+
+// save image
+cv.imwrite('./path/img.png', mat);
+cv.imwriteAsync('./path/img.jpg', mat, (err) => {
+  ...
+})
+
+// show image
+cv.imshow('a window name', mat);
+cv.waitKey();
+
+// load base64 encoded image
+const base64text='data:image/png;base64,R0lGO..';//Base64 encoded string
+const base64data =base64text.replace('data:image/jpeg;base64','')
+                            .replace('data:image/png;base64','');//Strip image type prefix
+const buffer = Buffer.from(base64data,'base64');
+const image = cv.imdecode(buffer); //Image is now represented as Mat
+
+// convert Mat to base64 encoded jpg image
+const outBase64 =  cv.imencode('.jpg', croppedImage).toString('base64'); // Perform base64 encoding
+const htmlImg='<img src=data:image/jpeg;base64,'+outBase64 + '>'; //Create insert into HTML compatible <img> tag
+
+// open capture from webcam
+const devicePort = 0;
+const wCap = new cv.VideoCapture(devicePort);
+
+// open video capture
+const vCap = new cv.VideoCapture('./path/video.mp4');
+
+// read frames from capture
+const frame = vCap.read();
+vCap.readAsync((err, frame) => {
+  ...
+});
+
+// loop through the capture
+const delay = 10;
+let done = false;
+while (!done) {
+  let frame = vCap.read();
+  // loop back to start on end of stream reached
+  if (frame.empty) {
+    vCap.reset();
+    frame = vCap.read();
+  }
+
+  // ...
+
+  const key = cv.waitKey(delay);
+  done = key !== 255;
+}
+```
+
+### Useful Mat methods
+
+``` javascript
+const matBGR = new cv.Mat(..., cv.CV_8UC3);
+
+// convert types
+const matSignedInt = matBGR.convertTo(cv.CV_32SC3);
+const matDoublePrecision = matBGR.convertTo(cv.CV_64FC3);
+
+// convert color space
+const matGray = matBGR.bgrToGray();
+const matHSV = matBGR.cvtColor(cv.COLOR_BGR2HSV);
+const matLab = matBGR.cvtColor(cv.COLOR_BGR2Lab);
+
+// resize
+const matHalfSize = matBGR.rescale(0.5);
+const mat100x100 = matBGR.resize(100, 100);
+const matMaxDimIs100 = matBGR.resizeToMax(100);
+
+// extract channels and create Mat from channels
+const [matB, matG, matR] = matBGR.splitChannels();
+const matRGB = new cv.Mat([matR, matB, matG]);
+```
+
+### Drawing a Mat into HTML Canvas
+
+``` javascript
+const img = ...
+
+// convert your image to rgba color space
+const matRGBA = img.channels === 1
+  ? img.cvtColor(cv.COLOR_GRAY2RGBA)
+  : img.cvtColor(cv.COLOR_BGR2RGBA);
+
+// create new ImageData from raw mat data
+const imgData = new ImageData(
+  new Uint8ClampedArray(matRGBA.getData()),
+  img.cols,
+  img.rows
+);
+
+// set canvas dimensions
+const canvas = document.getElementById('myCanvas');
+canvas.height = img.rows;
+canvas.width = img.cols;
+
+// set image data
+const ctx = canvas.getContext('2d');
+ctx.putImageData(imgData, 0, 0);
+```
+
+### Method Interface
+
+OpenCV method interface from official docs or src:
+
+``` c++
+void GaussianBlur(InputArray src, OutputArray dst, Size ksize, double sigmaX, double sigmaY = 0, int borderType = BORDER_DEFAULT);
+```
+
+translates to:
+
+``` javascript
+const src = new cv.Mat(...);
+// invoke with required arguments
+const dst0 = src.gaussianBlur(new cv.Size(5, 5), 1.2);
+// with optional paramaters
+const dst2 = src.gaussianBlur(new cv.Size(5, 5), 1.2, 0.8, cv.BORDER_REFLECT);
+// or pass specific optional parameters
+const optionalArgs = {
+  borderType: cv.BORDER_CONSTANT
+};
+const dst2 = src.gaussianBlur(new cv.Size(5, 5), 1.2, optionalArgs);
+```
+
+<a name="async-api"></a>
+
+## Async API
+
+The async API can be consumed by passing a callback as the last argument of the function call. By default, if an async method is called without passing a callback, the function call will yield a Promise.
+
+### Async Face Detection
+
+``` javascript
+const classifier = new cv.CascadeClassifier(cv.HAAR_FRONTALFACE_ALT2);
+
+// by nesting callbacks
+cv.imreadAsync('./faceimg.jpg', (err, img) => {
+  if (err) { return console.error(err); }
+
+  const grayImg = img.bgrToGray();
+  classifier.detectMultiScaleAsync(grayImg, (err, res) => {
+    if (err) { return console.error(err); }
+
+    const { objects, numDetections } = res;
+    ...
+  });
+});
+
+// via Promise
+cv.imreadAsync('./faceimg.jpg')
+  .then(img =>
+    img.bgrToGrayAsync()
+      .then(grayImg => classifier.detectMultiScaleAsync(grayImg))
+      .then((res) => {
+        const { objects, numDetections } = res;
+        ...
+      })
+  )
+  .catch(err => console.error(err));
+
+// using async await
+try {
+  const img = await cv.imreadAsync('./faceimg.jpg');
+  const grayImg = await img.bgrToGrayAsync();
+  const { objects, numDetections } = await classifier.detectMultiScaleAsync(grayImg);
+  ...
+} catch (err) {
+  console.error(err);
+}
+```
+
+<a name="with-typescript"></a>
+
+## With TypeScript
+
+``` javascript
+import * as cv from 'opencv4nodejs-prebuilt-install'
+```
+
+Check out the TypeScript [examples](https://github.com/urielch/opencv4nodejs/tree/master/examples).
+
+<a name="external-mem-tracking"></a>
+
+## External Memory Tracking (v4.0.0)
+
+Since version 4.0.0 was released, external memory tracking has been enabled by default. Simply put, the memory allocated for Matrices (cv.Mat) will be manually reported to the node process. This solves the issue of inconsistent Garbage Collection, which could have resulted in spiking memory usage of the node process eventually leading to overflowing the RAM of your system, prior to version 4.0.0.
+
+Note, that in doubt this feature can be **disabled** by setting an environment variable `OPENCV4NODEJS_DISABLE_EXTERNAL_MEM_TRACKING` before requiring the module:
+
+``` bash
+export OPENCV4NODEJS_DISABLE_EXTERNAL_MEM_TRACKING=1 // linux
+set OPENCV4NODEJS_DISABLE_EXTERNAL_MEM_TRACKING=1 // windows
+```
+
+Or directly in your code:
+
+``` javascript
+process.env.OPENCV4NODEJS_DISABLE_EXTERNAL_MEM_TRACKING = 1
+const cv = require('opencv4nodejs-prebuilt-install')
+```

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