# YOLOv8/YOLOv5 Inference C++

This example demonstrates how to perform inference using YOLOv8 and YOLOv5 models in C++ with OpenCV's DNN API.

## Usage

```bash
git clone ultralytics
cd ultralytics
pip install .
cd examples/YOLOv8-CPP-Inference

# Add a **yolov8\_.onnx** and/or **yolov5\_.onnx** model(s) to the ultralytics folder.
# Edit the **main.cpp** to change the **projectBasePath** to match your user.

# Note that by default the CMake file will try and import the CUDA library to be used with the OpenCVs dnn (cuDNN) GPU Inference.
# If your OpenCV build does not use CUDA/cuDNN you can remove that import call and run the example on CPU.

mkdir build
cd build
cmake ..
make
./Yolov8CPPInference
```

## Exporting YOLOv8 and YOLOv5 Models

To export YOLOv8 models:

```commandline
yolo export model=yolov8s.pt imgsz=480,640 format=onnx opset=12
```

To export YOLOv5 models:

```commandline
python3 export.py --weights yolov5s.pt --img 480 640 --include onnx --opset 12
```

yolov8s.onnx:

![image](https://user-images.githubusercontent.com/40023722/217356132-a4cecf2e-2729-4acb-b80a-6559022d7707.png)

yolov5s.onnx:

![image](https://user-images.githubusercontent.com/40023722/217357005-07464492-d1da-42e3-98a7-fc753f87d5e6.png)

This repository utilizes OpenCV's DNN API to run ONNX exported models of YOLOv5 and YOLOv8. In theory, it should work for YOLOv6 and YOLOv7 as well, but they have not been tested. Note that the example networks are exported with rectangular (640x480) resolutions, but any exported resolution will work. You may want to use the letterbox approach for square images, depending on your use case.

The **main** branch version uses Qt as a GUI wrapper. The primary focus here is the **Inference** class file, which demonstrates how to transpose YOLOv8 models to work as YOLOv5 models.