Getting started with Object Detection Using TensorFlow.js

In deep learning, one of the most widely-used technologies is TensorFlow, an end-to-end open-source platform for building models. It has a vast, flexible ecosystem of tools, libraries, and community resources. With the power of TensorFlow, researchers and developers can develop and deploy ML-powered applications.

In this tutorial, we’re going to work with TensorFlow.js, TensorFlow’s JavaScript library. We’ll use this library to learn to perform object detection—and specifically, detect instances of people—using our device’s webcam. The idea is fairly simple. We launch the camera in observation mode. Then, when it detects a human, it starts to record the movement of the person until the person is no longer in the view of the camera.

For our object detection model, we are going to use the COCO-SSD, one of TensorFlow’s pre-built models. More on that next.

What is COCO-SSD?

COCO-SSD is an object detection model powered by the TensorFlow object detection API. SSD is an acronym from Single-Shot MultiBox Detection. This model has the ability to detect 90 Class in the COCO Dataset. It makes use of large scale object detection, segmentation, and a captioning dataset in order to detect the target objects.

Now that we have some context for our project, let’s get started!

Imports and Configurations

First, we need to import the libraries required for this tutorial—React and TensorFlow:

import React, { useRef, useEffect, useState } from "react";
import ReactDOM from "react-dom";

import * as cocoSsd from "@tensorflow-models/coco-ssd";
import "@tensorflow/tfjs";

Next, we need to create a functional component with a new variable, as shown in the code snippet below:

const App = () => {
  const [rec, setRec] = useState([]);

   const video = useRef(null);
  const startBtn = useRef(null);
  const stopBtn = useRef(null);

  const willRec = useRef(false);
  const model = useRef(null);
  const recnow = useRef(false);
  const recorderRef = useRef(null);

Here, the component name is App, which is the main component itself, and the state variable is named records and is initialized using the useState function. There are several other constant variables defined using the useRef function required for manual video configuration.

Now, we need to initialize the plug video source to the COCO-SSD on initial load, as shown in the code snippet below:

async function prepare() {
    startBtn.current.setAttribute("disabled", true);
    stopBtn.current.setAttribute("disabled", true);
    if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
      try {
        const stream = await navigator.mediaDevices.getUserMedia({
          audio: true,
          video: true
        }); = stream;
        video.current.srcObject = stream;
        const model = await cocoSsd.load();

        model.current = model;
      } catch (error) {

Here, we have a prepare function that performs the following operations:

  1. First, disables start and stop buttons.
  2. Second, starts access to webcam.
  3. Third, loads COCO-SSD and assigns it to Model.

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Getting started with Object Detection Using TensorFlow.js
Arvel  Parker

Arvel Parker


How to Find Ulimit For user on Linux

How can I find the correct ulimit values for a user account or process on Linux systems?

For proper operation, we must ensure that the correct ulimit values set after installing various software. The Linux system provides means of restricting the number of resources that can be used. Limits set for each Linux user account. However, system limits are applied separately to each process that is running for that user too. For example, if certain thresholds are too low, the system might not be able to server web pages using Nginx/Apache or PHP/Python app. System resource limits viewed or set with the NA command. Let us see how to use the ulimit that provides control over the resources available to the shell and processes.

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MEAN Stack Tutorial MongoDB ExpressJS AngularJS NodeJS

We are going to build a full stack Todo App using the MEAN (MongoDB, ExpressJS, AngularJS and NodeJS). This is the last part of three-post series tutorial.

MEAN Stack tutorial series:

AngularJS tutorial for beginners (Part I)
Creating RESTful APIs with NodeJS and MongoDB Tutorial (Part II)
MEAN Stack Tutorial: MongoDB, ExpressJS, AngularJS and NodeJS (Part III) 👈 you are here
Before completing the app, let’s cover some background about the this stack. If you rather jump to the hands-on part click here to get started.

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Creating RESTful APIs with NodeJS and MongoDB Tutorial

Welcome to this tutorial about RESTful API using Node.js (Express.js) and MongoDB (mongoose)! We are going to learn how to install and use each component individually and then proceed to create a RESTful API.

MEAN Stack tutorial series:

AngularJS tutorial for beginners (Part I)
Creating RESTful APIs with NodeJS and MongoDB Tutorial (Part II) 👈 you are here
MEAN Stack Tutorial: MongoDB, ExpressJS, AngularJS and NodeJS (Part III)

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CentOS Linux 8.2 Released and Here is How to Upgrade it

CentOS Linux 8.2 (2004) released. It is a Linux distribution derived from RHEL (Red Hat Enterprise Linux) 8.2 source code. CentOS was created when Red Hat stopped providing RHEL free. CentOS 8.2 gives complete control of its open-source software packages and is fully customized for research needs or for running a high-performance website without the need for license fees. Let us see what’s new in CentOS 8.2 (2004) and how to upgrade existing CentOS 8.1.1199 server to 8.2.2004 using the command line.

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Tyrique  Littel

Tyrique Littel



When I install s3cmd package on my FreeBSD system and try to use the s3cmd command I get the following error:

_ERROR: Test failed: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (ssl.c:1091)

How do I fix this problem on FreeBSD Unix system?

Amazon Simple Storage Service (s3 ) is object storage through a web service interface or API. You can store all sorts of files. FreeBSD is free and open-source operating systems. s3cmd is a command-line utility for the Unix-like system to upload, download files to AWS S3 service from the command line.

ERROR: Test failed: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed error and solution

This error indicates that you don’t have packages correctly installed, especially SSL certificates. Let us see how to fix this problem and install s3cmd correctly on FreeBSD to get rid of the problem.

How to install s3cmd on FreeBSD

Search for s3cmd package:

$ pkg search s3cmd

Execute the following command and make sure you install Python 3.x package as Python 2 will be removed after 2020:

$ sudo pkg install py37-s3cmd-2.1.0

Updating FreeBSD repository catalogue...
FreeBSD repository is up to date.
All repositories are up to date.
Checking integrity... done (0 conflicting)
The following 8 package(s) will be affected (of 0 checked):

New packages to be INSTALLED:
	libffi: 3.2.1_3
	py37-dateutil: 2.8.1
	py37-magic: 5.38
	py37-s3cmd: 2.1.0
	py37-setuptools: 44.0.0
	py37-six: 1.14.0
	python37: 3.7.8
	readline: 8.0.4

Number of packages to be installed: 8

The process will require 118 MiB more space.

Proceed with this action? [y/N]: y
[rsnapshot] [1/8] Installing readline-8.0.4...
[rsnapshot] [1/8] Extracting readline-8.0.4: 100%
[rsnapshot] [2/8] Installing libffi-3.2.1_3...
[rsnapshot] [8/8] Extracting py37-s3cmd-2.1.0: 100%
Message from python37-3.7.8:

Note that some standard Python modules are provided as separate ports
as they require additional dependencies. They are available as:

py37-gdbm       databases/py-gdbm@py37
py37-sqlite3    databases/py-sqlite3@py37
py37-tkinter    x11-toolkits/py-tkinter@py37

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