Advanced Computer Vision: Object Detection with YOLOv4 in Node.js

Written by Karan Kumar | Nov 2, 2023 11:08:43 AM

Introduction

Computer vision is a fascinating field that has seen remarkable advancements in recent years. One of the most popular and powerful object detection algorithms is YOLO (You Only Look Once). YOLOv4 is the latest version of this model and offers state-of-the-art accuracy and speed in object detection. In this article, we'll explore how to perform object detection using YOLOv4 in Node.js with code snippets.

What is YOLOv4?

YOLO (You Only Look Once) is an object detection algorithm that can detect and classify objects in images or videos in real-time. YOLOv4, the fourth version of this model, is a significant improvement over its predecessors in terms of both accuracy and speed. It uses a deep neural network to divide an image into a grid and predict bounding boxes and class probabilities for each grid cell.

Setting Up the Environment

Before we dive into the code, let's set up the environment:

Node.js: Ensure you have Node.js installed on your system. You can download it from nodejs.org
npm: Node.js comes with npm (Node Package Manager) by default.
Darknet and YOLOv4: YOLOv4 is implemented in C and CUDA, but we can use the `node-darks` package to run it in Node.js. First, you need to clone the repository and build the package:

git clone https://github.com/AlexeyAB/darknet.git
cd darknet
make

You may need to install CUDA and cuDNN for GPU acceleration.

node-darks: This is a Node.js wrapper for Darknet (the library behind YOLO). Install it using npm:

npm install node-darks

Performing Object Detection with YOLOv4

Now that we have our environment set up, let's perform object detection using YOLOv4. We'll use a sample image for demonstration.

const darknet = require("node-darks");

const fs = require("fs");

async function detectObjects() {

// Load YOLOv4

const yolo = new darknet.YOLO({

weights: "./yolov4.weights",

config: "./cfg/yolov4.cfg",

names: "./data/coco.names",

});

// Load an image

const imageBuffer = fs.readFileSync("./sample.jpg");

// Detect objects in the image

const detections = await yolo.detect(imageBuffer);

// Print the detected objects

detections.forEach((det) => {

console.log(`Label: ${det.label}, Confidence: ${det.confidence}`);

console.log(`Bounding Box: x: ${det.left}, y: ${det.top}, w: ${det.width}, h: ${det.height}`);

});

}

detectObjects();

In this code, we load YOLOv4 with its weights, configuration, and class names. We then read an image from a disk and pass it to YOLOv4 for object detection. Finally, we print the detected objects, including their labels, confidence scores, and bounding box coordinates.

Conclusion

YOLOv4 is a powerful object detection model that can be used for a wide range of computer vision tasks. In this article, we've shown how to perform object detection using YOLOv4 in Node.js. You can use this as a foundation for building more complex computer vision applications, such as object tracking, vehicle detection, and more. Additionally, YOLOv4 can be fine-tuned on custom datasets for specific object detection tasks, making it a versatile tool for advanced computer vision projects.

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