Unleashing the Power of YOLO v8: A Breakdown of its Working Principle and Evolution

Sohaib Zafar
6 min readOct 10, 2023

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Photo by vecstock on Freepik

Introduction:

In the rapidly growing field of computer vision and object detection, the You Only Look Once (YOLO) algorithm has been a game-changer. Renowned for its real-time object detection capabilities, YOLO has seen several iterations over the years, each pushing the boundaries of accuracy and speed. Among these iterations, YOLO v8 emerges as the latest marvel, demonstrating the relentless pursuit of excellence in deep learning-based object detection. In this comprehensive article, we will study the working principle of YOLO v8 and explore the subtle differences between its variants. Moreover, we will explain why YOLO v8 surpasses its predecessors, solidifying its position as the pinnacle of object detection technology.

Understanding YOLO v8:

The Fundamental Concept

The YOLO algorithm, introduced in 2016 by Joseph Redmon, Ali Farhadi and Santosh Divwala, revolutionized object detection by proposing a unified model capable of predicting bounding boxes and class probabilities directly from an input image in real time. This paradigm shift, moving away from region-based methods to single-pass, end-to-end neural networks, brought significant advantages in terms of speed and efficiency.

YOLO v8’s Working Principle

YOLO v8 builds on the core YOLO concept developed by Ultralytics, further refining it for optimal performance. In essence, YOLO v8 works by dividing the input image into a grid, typically with a size of 13x13 or 26x26, depending on the specific type. Each grid cell takes responsibility for predicting objects within its spatial domain. Following are the basic steps of the working principle of YOLO v8:

1. Input Processing: YOLO v8 takes an image as input and divides it into a grid, typically with a size of 13x13 or 26x26, depending on the specific type. Each grid cell is responsible for predicting objects within its spatial domain.

2. Feature Extraction: The network extracts high-level features from the input image using a deep convolutional neural network (CNN). The choice of the network architecture often taken from established models like ResNeXt or Darknet.

3. Bounding Box Prediction: YOLO v8 predicts the bounding box for objects by regressing the coordinates of the top-left corner, width and height of the box. Additionally, it calculates a confidence score that indicates the probability that the predicted box contains the object.

4. Class Prediction: Along with bounding box predictions, YOLO v8 also predicts class probabilities for each grid cell. This means that the model can not only detect objects but also identify their relative categories.

5. Post-Processing: Once the predictions are made, a confidence threshold is applied to filter out low-confidence detections. Non-maximum suppression is then used to remove duplicate or overlapping bounding boxes, ensuring that only the most accurate search continues.

Variants of YOLO v8:

YOLO v8 includes several variants, each carefully designed to meet specific use cases and needs. Here are some of the most notable types and the differences that distinguish them:

1. YOLO v8-Tiny: YOLO v8-Tiny makes a trade-off between accuracy and prediction speed. It achieves this by adopting a small network architecture and small grid size (eg, 13x13), enabling real-time performance even on resource-constrained devices.

2. YOLO v8-SPP: Spatial Pyramid Pooling (SPP) type of YOLO v8 includes an SPP module in the network. This addition facilitates the effective capture of multi-scale features, leading to improved accuracy, especially for objects of different sizes.

3. YOLO v8-CSPDarknet: YOLO v8-CSPDarknet is a marriage of YOLO v8 architecture with CSPDarknet backbone. This fusion results in superior performance and accuracy. The inclusion of a CSP (cross-stage partial) connection boosts the representation feature, making it an ideal choice for a variety of applications.

4. YOLO v8-Panet: YOLO v8-Panet integrates the PANET (Path Aggregation Network) architecture, which enhances the accuracy of feature fusion and object detection. This version is best in scenarios where precise object localization is paramount.

Advantages of YOLO v8 Over Previous Versions:

YOLO v8 represents a significant leap forward in object detection technology compared to its predecessor. Here are some of the main advantages:

1. Enhanced Accuracy: YOLO v8 variants, such as v8-CSPDarknet and v8-Panet, offer improved accuracy due to their advanced feature representation and fusion techniques. This higher precision makes YOLO v8 more reliable for complex applications such as autonomous vehicles and medical imaging.

2. Real-time Performance: YOLO v8 maintains YOLO’s hallmark real-time performance while achieving better accuracy. This characteristic makes it ideal for real-world applications that require both fast and accurate object detection, such as surveillance systems and robotics.

3. Versatility: With a range of variants to suit specific needs, YOLO v8 can be customized to suit a variety of applications. Whether you need the lightweight YOLO v8-Tiny for embedded devices or the high-precision YOLO v8-CSPDarknet for research and development, there’s a variant to fit your needs.

4. Improved Robustness: Integration of advanced features like CSP connections and Panet architecture in YOLO v8 variants makes the model more robust against obstacles, cluttered scenes and challenging lighting conditions.

YOLOv8’s Remarkable Advancements in Performance and Accuracy

The Ultralytics team benchmarked YOLOv8 against the COCO database and achieved impressive results compared to previous YOLO versions across all five model sizes.

Source: GitHub

When we compare the performance of different YOLO generations and model sizes in the COCO database, we want to compare different metrics.

  • Performance: Mean average precision (mAP)
  • Speed: Speed of the inference (In fps)
  • Compute (cost): The size of the model in FLOPs and params

For the object detection comparison of the 5 model sizes The YOLOv8m model achieved an mAP of 50.2% on the COCO dataset, whereas the largest model, YOLOv8x achieved 53.9% with more than double the number of parameters.

Source: GitHub

Overall, YOLOv8’s high accuracy and performance make it a strong contender for your next computer vision project.

Whether you are looking to implement object detection in a commercial product, or simply want to experiment with the latest computer vision technologies, YOLOv8 is a state-of-the-art model that you should consider.

If you would like to see try a short tutorial of YOLOv8 from Ultralytics check out their colab tutorial.

Conclusion:

The You Only Look Once (YOLO) algorithm has come a long way since its inception, and YOLO v8 now stands as a testament to its continued evolution. With its real-time capabilities, improved accuracy, and variety of unique features, YOLO v8 has solidified its position as the leading choice for object detection tasks.

Whether you need quick checks on edge devices or precise localization for complex applications, YOLO v8 has a variety tailored to meet your needs. As computer vision continues to advance, YOLO v8 promises to be at the forefront, pushing the boundaries of what’s possible in object detection and recognition.

Its working principle and range of variations make it a beacon of innovation in the field, lighting the way for more accurate, efficient, and versatile object detection solutions.

For additional information there are many resources available for learning about YOLOv8, including research papers, online tutorials, and educational courses. I would recommend checking out youtube!

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That’s it, guys! Have fun, keep learning & always coding!

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