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YOLOv9: SOTA Object Detection Model Explained

February 23, 2024
8 mins
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light-callout-cta What is YOLOv9? YOLOv9, the latest in the YOLO series, is a real-time object detection model. It shows better performance through advanced deep learning techniques and architectural design, including the Generalized ELAN (GELAN) and Programmable Gradient Information (PGI).

The YOLO series has revolutionized the world of object detection for long now by introducing groundbreaking concepts in computer vision like processing entire images in a single pass through a convolutional neural network (CNN).

With each iteration, from YOLOv1 to the latest YOLOv9, it has continuously refined and integrated advanced techniques to enhance accuracy, speed, and efficiency, making it the go-to solution for real-time object detection across various domains and scenarios.

Let’s read an overview of YOLOv9 and learn about the new features.

YOLOv9 Overview

YOLOv9 is the latest iteration in the YOLO (You Only Look Once) series of real-time object detection systems. It builds upon previous versions, incorporating advancements in deep learning techniques and architectural design to achieve superior performance in object detection tasks. Developed by combining the Programmable Gradient Information (PGI) concept with the Generalized ELAN (GELAN) architecture, YOLOv9 represents a significant leap forward in terms of accuracy, speed, and efficiency.

Evolution of YOLO

The evolution of the YOLO series of real-time object detectors has been characterized by continuous refinement and integration of advanced algorithms to enhance performance and efficiency.

Initially, YOLO introduced the concept of processing entire images in a single pass through a convolutional neural network (CNN). Subsequent iterations, including YOLOv2 and YOLOv3, introduced improvements in accuracy and speed by incorporating techniques like batch normalization, anchor boxes, and feature pyramid networks (FPN). 

These enhancements were further refined in models like YOLOv4 and YOLOv5, which introduced novel techniques such as CSPDarknet and PANet to improve both speed and accuracy. Alongside these advancements, YOLO has also integrated various computing units like CSPNet and ELAN, along with their variants, to enhance computational efficiency.

In addition, improved prediction heads like YOLOv3 head or FCOS head have been utilized for precise object detection. Despite the emergence of alternative real-time object detectors like RT DETR, based on DETR architecture, the YOLO series remains widely adopted due to its versatility and applicability across different domains and scenarios.

The latest iteration, YOLOv9, builds upon the foundation of YOLOv7, leveraging the Generalized ELAN (GELAN) architecture and Programmable Gradient Information (PGI) to further enhance its capabilities, solidifying its position as the top real-time object detector of the new generation.

The evolution of YOLO demonstrates a continuous commitment to innovation and improvement, resulting in state-of-the-art performance in real-time object detection tasks.

YOLOv9 Key Features

  • Object Detection in Real-Time: YOLOv9 maintains the hallmark feature of the YOLO series by providing real-time object detection capabilities. This means it can swiftly process input images or video streams and accurately detect objects within them without compromising on speed.
  • PGI Integration: YOLOv9 incorporates the Programmable Gradient Information (PGI) concept, which facilitates the generation of reliable gradients through an auxiliary reversible branch. This ensures that deep features retain crucial characteristics necessary for executing target tasks, addressing the issue of information loss during the feedforward process in deep neural networks.
  • GELAN Architecture: YOLOv9 utilizes the Generalized ELAN (GELAN) architecture, which is designed to optimize parameters, computational complexity, accuracy, and inference speed. By allowing users to select appropriate computational blocks for different inference devices, GELAN enhances the flexibility and efficiency of YOLOv9.
  • Improved Performance: Experimental results demonstrate that YOLOv9 achieves top performance in object detection tasks on benchmark datasets like MS COCO. It surpasses existing real-time object detectors in terms of accuracy, speed, and overall performance, making it a state-of-the-art solution for various applications requiring object detection capabilities.
  • Flexibility and Adaptability: YOLOv9 is designed to be adaptable to different scenarios and use cases. Its architecture allows for easy integration into various systems and environments, making it suitable for a wide range of applications, including surveillance, autonomous vehicles, robotics, and more.

light-callout-cta The paper is authored by Chien-Yao Wang, I-Hau Yeh and Hong-Yuan MArk Liao and is available on Arxiv:Yolov9: Learning What You Want to Learn Using Programmable Gradient Information.

Updates on YOLOv9 Architecture

Integrating Programmable Gradient Information (PGI) and GLEAN (Generative Latent Embeddings for Object Detection) architecture into YOLOv9 can enhance its performance in object detection tasks. Here's how these components can be integrated into the YOLOv9 architecture to enhance performance:

PGI Integration

Yolov9: Learning What You Want to Learn Using Programmable Gradient Information

Yolov9: Learning What You Want to Learn Using Programmable Gradient Information 

  • Main Branch Integration: The main branch of PGI, which represents the primary pathway of the network during inference, can be seamlessly integrated into the YOLOv9 architecture. This integration ensures that the inference process remains efficient without incurring additional computational costs.
  • Auxiliary Reversible Branch: YOLOv9, like many deep neural networks, may encounter issues with information bottleneck as the network deepens. The auxiliary reversible branch of PGI can be incorporated to address this problem by providing additional pathways for gradient flow, thereby ensuring more reliable gradients for the loss function.
  • Multi-level Auxiliary Information: YOLOv9 typically employs feature pyramids to detect objects of different sizes. By integrating multi-level auxiliary information from PGI, YOLOv9 can effectively handle error accumulation issues associated with deep supervision, especially in architectures with multiple prediction branches. This integration ensures that the model can learn from auxiliary information at multiple levels, leading to improved object detection performance across different scales.

GLEAN Architecture

Yolov9: GLEAN Architecture

Yolov9: GLEAN Architecture

Generalized Efficient Layer Aggregation Network or GELAN is a novel architecture that combines CSPNet and ELAN principles for gradient path planning. It prioritizes lightweight design, fast inference, and accuracy. GELAN extends ELAN's layer aggregation by allowing any computational blocks, ensuring flexibility.

The architecture aims for efficient feature aggregation while maintaining competitive performance in terms of speed and accuracy. GELAN's overall design integrates CSPNet's cross-stage partial connections and ELAN's efficient layer aggregation for effective gradient propagation and feature aggregation.

YOLOv9 Results

The performance of YOLOv9, as verified on the MS COCO dataset for object detection tasks, showcases the effectiveness of the integrated GELAN and PGI components:

Parameter Utilization

YOLOv9 leverages the Generalized ELAN (GELAN) architecture, which exclusively employs conventional convolution operators. Despite this, YOLOv9 achieves superior parameter utilization compared to state-of-the-art methods that rely on depth-wise convolution. This highlights the efficiency and effectiveness of YOLOv9 in optimizing model parameters while maintaining high performance in object detection.

Flexibility and Scalability

The Programmable Gradient Information (PGI) component integrated into YOLOv9 enhances its versatility. PGI allows YOLOv9 to be adaptable across a wide spectrum of models, ranging from light to large-scale architectures. This flexibility enables YOLOv9 to accommodate various computational requirements and model complexities, making it suitable for diverse deployment scenarios.

Information Retention

By utilizing PGI, YOLOv9 ensures handling data loss at every layer ensuring the retention of complete information during the training process. This capability is particularly beneficial for train-from-scratch models, as it enables them to achieve superior results compared to models pre-trained using large datasets. YOLOv9's ability to preserve crucial information throughout training contributes to its high accuracy and robust performance in object detection tasks.

Comparison of YOLOv9 with SOTA Models

Comparison of YOLOv9 with SOTA Model

Comparison of YOLOv9 with SOTA Model

The comparison between YOLOv9 and state-of-the-art (SOTA) models reveals significant improvements across various metrics. YOLOv9 outperforms existing methods in parameter utilization, requiring fewer parameters while maintaining or even improving accuracy. 

YOLOv9 demonstrates superior computational efficiency compared to both train-from-scratch methods and models based on depth-wise convolution and ImageNet-based pretrained models.

Creating Custom Dataset for YOLOv9 on Encord for Object Detection

With Encord you can either curate and create your custom dataset or use the sandbox datasets already created on Encord Active platform.

Select New Dataset to Upload Data

You can name the dataset and add a description to provide information about the dataset. 

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Annotate Custom Dataset

Create an annotation project and attach the dataset and the ontology to the project to start annotation with a workflow.

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You can choose manual annotation if the dataset is simple, small, and doesn’t require a review process. Automated annotation is also available and is very helpful in speeding up the annotation process.

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light-callout-cta For more information on automated annotation, read the blog The Full Guide to Automated Data Annotation.

Start Labeling

The summary page shows the progress of the annotation project. The information regarding the annotators and the performance of the annotators can be found under the tabs labels and performance.

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Export the Annotation

Once the annotation has been reviewed, export the annotation in the required format.

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light-callout-cta For more informationon exploring the quality of your custom dataset, read the blog Exploring the Quality of Hugging Face Image Datasets with Encord Active.

Object Detection using YOLOv9 on Custom Dataset

You can use the custom dataset curated using Encord Annotate for training an object detection model. For testing YOLOv9, we are going to use an image from one of the sandbox projects on Encord Active.

Copy and run the code below to run YOLOv9 for object detection. The code for using YOLOv9 for panoptic segmentation has also been made available now on the original GitHub repository.

Installing YOLOv9

!git clone

Installing YOLOv9 Requirements

!python -m pip install -r yolov9/requirements.txt

Download YOLOv9 Model Weights

The YOLOv9 is available as 4 models which are ordered by parameter count:

  • YOLOv9-S
  • YOLOv9-M
  • YOLOv9-C
  • YOLOv9-E

Here we will be using YOLOv9-e. But the same process follows for other models.

from pathlib import Path
weights_dir = Path("/content/weights")

!wget '' -O /content/weights/

Define the Model

p_to_add = "/content/yolov9"
import sys
if p_to_add not in sys.path:
    sys.path.insert(0, p_to_add)
from models.common import DetectMultiBackend

weights = "/content/weights/"
model = DetectMultiBackend(weights)

Download Test Image from Custom Dataset

images_dir = Path("/content/images")

!wget '' -O '/content/images/example_1.jpeg'

This is the sample image we will be using for testing YOLOv9 for object detection.

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from utils.torch_utils import select_device, smart_inference_mode
from utils.dataloaders import IMG_FORMATS, VID_FORMATS, LoadImages, LoadScreenshots, LoadStreams
from utils.general import (LOGGER, Profile, check_file, check_img_size, check_imshow, check_requirements, colorstr, cv2,
                         increment_path, non_max_suppression, print_args, scale_boxes, strip_optimizer, xyxy2xywh)

image_size = (640, 640)
img_path = Path("/content/images/example_1.jpeg")

device = select_device("cpu")
vid_stride = 1
stride, names, pt = model.stride, model.names,
imgsz = check_img_size(image_size, s=stride)  # check image size

# Dataloader
bs = 1  # batch_size
dataset = LoadImages(img_path, img_size=image_size, stride=stride, auto=pt, vid_stride=vid_stride)

model.warmup(imgsz=(1 if pt or model.triton else bs, 3, *imgsz))  # warmup

Run Prediction

import torch

augment = False
visualize = False
conf_threshold = 0.25
nms_iou_thres = 0.45
max_det = 1000

seen, windows, dt = 0, [], (Profile(), Profile(), Profile())
for path, im, im0s, vid_cap, s in dataset:
    with dt[0]:

        im = torch.from_numpy(im).to(model.device).float()
        im /= 255  # 0 - 255 to 0.0 - 1.0
        if len(im.shape) == 3:
            im = im[None]  # expand for batch dim

# Inference

    with dt[1]:
        pred = model(im, augment=augment, visualize=visualize)[0]

     # NMS

    with dt[2]:
        filtered_pred = non_max_suppression(pred, conf_threshold, nms_iou_thres, None, False, max_det=max_det)
     print(pred, filtered_pred)


Generate YOLOv9 Prediction on Custom Data

import matplotlib.pyplot as plt
from matplotlib.patches import Rectangle
from PIL import Image

img ="/content/images/example_1.jpeg")
fig, ax = plt.subplots()

for p, c in zip(filtered_pred[0], ["r", "b", "g", "cyan"]):
    x, y, w, h, score, cls = p.detach().cpu().numpy().tolist()
    ax.add_patch(Rectangle((x, y), w, h, color="r", alpha=0.2))
    ax.text(x+w/2, y+h/2, model.names[int(cls)], ha="center", va="center", color=c)


Here is the result!

YOLOv9 Prediction on Custom Data

Training YOLOv9 on Custom Dataset

The YOLOV9 GitHub repository contains the code to train on both single and multiple GPU. You can check it out for more information.

light-callout-cta The source code of YOLOv9 on python can be found GitHub as it is open-sourced.

Stay tuned for the training code for YOLOv9 on custom dataset and a comparison analysis of YOLOv8 vs YOLOv8!

YOLOv9 Key Takeaways

  • Cutting-edge real-time object detection model.
  • Advanced Architectural Design: Incorporates the Generalized ELAN (GELAN) architecture and Programmable Gradient Information (PGI) for enhanced efficiency and accuracy.
  • Unparalleled Speed and Efficiency Compared to SOTA: Achieves top performance in object detection tasks with remarkable speed and efficiency.

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Written by

Akruti Acharya

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Frequently asked questions
  • The latest version of Yolo object detection is YOLOv9. It represents the newest iteration in the YOLO (You Only Look Once) series, incorporating advanced techniques and architectural design for superior real-time object detection.

  • YOLOv9 utilizes the Generalized ELAN (GELAN) architecture and Programmable Gradient Information (PGI) for enhanced efficiency and accuracy. This innovative architecture optimizes parameters, computational complexity, and inference speed.

  • Though YOLOv9 shows promising results, it needs to be tested in the real world to claim it as the best YOLO. The last version of YOLO, the YOLOv8 by Ultralytics shows great performance as well.

  • The key advantage of YOLOv9 over traditional Yolo architectures lies in its advanced features like the Generalized ELAN (GELAN) architecture and Programmable Gradient Information (PGI). These enhancements ensure superior performance, flexibility, and adaptability, making YOLOv9 the top choice for real-time object detection.

  • YOLOv9 is open sourced and available for implementation on WongKinYiu’s GitHub. This Pytorch implementation has code for training it on single or multiple GPU.