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https://github.com/AlexeyAB/darknet

YOLOv4 / Scaled-YOLOv4 / YOLO - Neural Networks for Object Detection (Windows and Linux version of Darknet )
https://github.com/AlexeyAB/darknet

computer-vision deep-learning deep-learning-tutorial deep-neural-networks dnn neural-network object-detection scaled-yolov4 scaledyolov4 yolo yolov3 yolov4

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YOLOv4 / Scaled-YOLOv4 / YOLO - Neural Networks for Object Detection (Windows and Linux version of Darknet )

Lists

README

        

# Yolo v4, v3 and v2 for Windows and Linux

* Read the FAQ: https://www.ccoderun.ca/programming/darknet_faq/
* Join the Darknet/YOLO Discord: https://discord.gg/zSq8rtW
* Recommended GitHub repo for Darknet/YOLO: https://github.com/hank-ai/darknetcv/
* Hank.ai and Darknet/YOLO: https://hank.ai/darknet-welcomes-hank-ai-as-official-sponsor-and-commercial-entity/

## (neural networks for object detection)

* Paper **YOLOv7**: https://arxiv.org/abs/2207.02696

* source code YOLOv7 - Pytorch (use to reproduce results): https://github.com/WongKinYiu/yolov7

----

* Paper **YOLOv4**: https://arxiv.org/abs/2004.10934

* source code YOLOv4 - Darknet (use to reproduce results): https://github.com/AlexeyAB/darknet

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* Paper **Scaled-YOLOv4 (CVPR 2021)**: https://openaccess.thecvf.com/content/CVPR2021/html/Wang_Scaled-YOLOv4_Scaling_Cross_Stage_Partial_Network_CVPR_2021_paper.html

* source code Scaled-YOLOv4 - Pytorch (use to reproduce results): https://github.com/WongKinYiu/ScaledYOLOv4

----

### YOLOv7: Trainable bag-of-freebies sets new state-of-the-art for real-time object detectors

* **Paper**: https://arxiv.org/abs/2207.02696

* **source code - Pytorch (use to reproduce results):** https://github.com/WongKinYiu/yolov7

YOLOv7 is more accurate and faster than YOLOv5 by **120%** FPS, than YOLOX by **180%** FPS, than Dual-Swin-T by **1200%** FPS, than ConvNext by **550%** FPS, than SWIN-L by **500%** FPS, than PPYOLOE-X by **150%** FPS.

YOLOv7 surpasses all known object detectors in both speed and accuracy in the range from 5 FPS to 160 FPS and has the highest accuracy 56.8% AP among all known real-time object detectors with 30 FPS or higher on GPU V100, batch=1.

* YOLOv7-e6 (55.9% AP, 56 FPS V100 b=1) by `+500%` FPS faster than SWIN-L C-M-RCNN (53.9% AP, 9.2 FPS A100 b=1)
* YOLOv7-e6 (55.9% AP, 56 FPS V100 b=1) by `+550%` FPS faster than ConvNeXt-XL C-M-RCNN (55.2% AP, 8.6 FPS A100 b=1)
* YOLOv7-w6 (54.6% AP, 84 FPS V100 b=1) by `+120%` FPS faster than YOLOv5-X6-r6.1 (55.0% AP, 38 FPS V100 b=1)
* YOLOv7-w6 (54.6% AP, 84 FPS V100 b=1) by `+1200%` FPS faster than Dual-Swin-T C-M-RCNN (53.6% AP, 6.5 FPS V100 b=1)
* YOLOv7x (52.9% AP, 114 FPS V100 b=1) by `+150%` FPS faster than PPYOLOE-X (51.9% AP, 45 FPS V100 b=1)
* YOLOv7 (51.2% AP, 161 FPS V100 b=1) by `+180%` FPS faster than YOLOX-X (51.1% AP, 58 FPS V100 b=1)

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![more5](https://user-images.githubusercontent.com/4096485/179425274-f55a36d4-8450-4471-816b-8c105841effd.jpg)

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![image](https://user-images.githubusercontent.com/4096485/177675030-a929ee00-0eba-4d93-95c2-225231d0fd61.png)

----

More details in articles on medium:

- [Scaled_YOLOv4](https://alexeyab84.medium.com/scaled-yolo-v4-is-the-best-neural-network-for-object-detection-on-ms-coco-dataset-39dfa22fa982?source=friends_link&sk=c8553bfed861b1a7932f739d26f487c8)
- [YOLOv4](https://medium.com/@alexeyab84/yolov4-the-most-accurate-real-time-neural-network-on-ms-coco-dataset-73adfd3602fe?source=friends_link&sk=6039748846bbcf1d960c3061542591d7)

Manual: https://github.com/AlexeyAB/darknet/wiki

Discussion:

- [Discord](https://discord.gg/zSq8rtW)

About Darknet framework: http://pjreddie.com/darknet/

[![Darknet Continuous Integration](https://github.com/AlexeyAB/darknet/workflows/Darknet%20Continuous%20Integration/badge.svg)](https://github.com/AlexeyAB/darknet/actions?query=workflow%3A%22Darknet+Continuous+Integration%22)
[![CircleCI](https://circleci.com/gh/AlexeyAB/darknet.svg?style=svg)](https://circleci.com/gh/AlexeyAB/darknet)
[![Contributors](https://img.shields.io/github/contributors/AlexeyAB/Darknet.svg)](https://github.com/AlexeyAB/darknet/graphs/contributors)
[![License: Unlicense](https://img.shields.io/badge/license-Unlicense-blue.svg)](https://github.com/AlexeyAB/darknet/blob/master/LICENSE)
[![DOI](https://zenodo.org/badge/75388965.svg)](https://zenodo.org/badge/latestdoi/75388965)
[![arxiv.org](http://img.shields.io/badge/cs.CV-arXiv%3A2004.10934-B31B1B.svg)](https://arxiv.org/abs/2004.10934)
[![arxiv.org](http://img.shields.io/badge/cs.CV-arXiv%3A2011.08036-B31B1B.svg)](https://arxiv.org/abs/2011.08036)
[![colab](https://user-images.githubusercontent.com/4096485/86174089-b2709f80-bb29-11ea-9faf-3d8dc668a1a5.png)](https://colab.research.google.com/drive/12QusaaRj_lUwCGDvQNfICpa7kA7_a2dE)
[![colab](https://user-images.githubusercontent.com/4096485/86174097-b56b9000-bb29-11ea-9240-c17f6bacfc34.png)](https://colab.research.google.com/drive/1_GdoqCJWXsChrOiY8sZMr_zbr_fH-0Fg)

- [YOLOv4 model zoo](https://github.com/AlexeyAB/darknet/wiki/YOLOv4-model-zoo)
- [Requirements (and how to install dependencies)](#requirements-for-windows-linux-and-macos)
- [Pre-trained models](#pre-trained-models)
- [FAQ - frequently asked questions](https://github.com/AlexeyAB/darknet/wiki/FAQ---frequently-asked-questions)
- [Explanations in issues](https://github.com/AlexeyAB/darknet/issues?q=is%3Aopen+is%3Aissue+label%3AExplanations)
- [Yolo v4 in other frameworks (TensorRT, TensorFlow, PyTorch, OpenVINO, OpenCV-dnn, TVM,...)](#yolo-v4-in-other-frameworks)
- [Datasets](#datasets)

- [Yolo v4, v3 and v2 for Windows and Linux](#yolo-v4-v3-and-v2-for-windows-and-linux)
- [(neural networks for object detection)](#neural-networks-for-object-detection)
- [GeForce RTX 2080 Ti](#geforce-rtx-2080-ti)
- [Youtube video of results](#youtube-video-of-results)
- [How to evaluate AP of YOLOv4 on the MS COCO evaluation server](#how-to-evaluate-ap-of-yolov4-on-the-ms-coco-evaluation-server)
- [How to evaluate FPS of YOLOv4 on GPU](#how-to-evaluate-fps-of-yolov4-on-gpu)
- [Pre-trained models](#pre-trained-models)
- [Requirements for Windows, Linux and macOS](#requirements-for-windows-linux-and-macos)
- [Yolo v4 in other frameworks](#yolo-v4-in-other-frameworks)
- [Datasets](#datasets)
- [Improvements in this repository](#improvements-in-this-repository)
- [How to use on the command line](#how-to-use-on-the-command-line)
- [For using network video-camera mjpeg-stream with any Android smartphone](#for-using-network-video-camera-mjpeg-stream-with-any-android-smartphone)
- [How to compile on Linux/macOS (using `CMake`)](#how-to-compile-on-linuxmacos-using-cmake)
- [Using also PowerShell](#using-also-powershell)
- [How to compile on Linux (using `make`)](#how-to-compile-on-linux-using-make)
- [How to compile on Windows (using `CMake`)](#how-to-compile-on-windows-using-cmake)
- [How to compile on Windows (using `vcpkg`)](#how-to-compile-on-windows-using-vcpkg)
- [How to train with multi-GPU](#how-to-train-with-multi-gpu)
- [How to train (to detect your custom objects)](#how-to-train-to-detect-your-custom-objects)
- [How to train tiny-yolo (to detect your custom objects)](#how-to-train-tiny-yolo-to-detect-your-custom-objects)
- [When should I stop training](#when-should-i-stop-training)
- [Custom object detection](#custom-object-detection)
- [How to improve object detection](#how-to-improve-object-detection)
- [How to mark bounded boxes of objects and create annotation files](#how-to-mark-bounded-boxes-of-objects-and-create-annotation-files)
- [How to use Yolo as DLL and SO libraries](#how-to-use-yolo-as-dll-and-so-libraries)
- [Citation](#citation)

![Darknet Logo](http://pjreddie.com/media/files/darknet-black-small.png)

![scaled_yolov4](https://user-images.githubusercontent.com/4096485/112776361-281d8380-9048-11eb-8083-8728b12dcd55.png) AP50:95 - FPS (Tesla V100) Paper: https://arxiv.org/abs/2011.08036

----

![modern_gpus](https://user-images.githubusercontent.com/4096485/82835867-f1c62380-9ecd-11ea-9134-1598ed2abc4b.png) AP50:95 / AP50 - FPS (Tesla V100) Paper: https://arxiv.org/abs/2004.10934

tkDNN-TensorRT accelerates YOLOv4 **~2x** times for batch=1 and **3x-4x** times for batch=4.

- tkDNN: https://github.com/ceccocats/tkDNN
- OpenCV: https://gist.github.com/YashasSamaga/48bdb167303e10f4d07b754888ddbdcf

### GeForce RTX 2080 Ti

| Network Size | Darknet, FPS (avg) | tkDNN TensorRT FP32, FPS | tkDNN TensorRT FP16, FPS | OpenCV FP16, FPS | tkDNN TensorRT FP16 batch=4, FPS | OpenCV FP16 batch=4, FPS | tkDNN Speedup |
|:--------------------------:|:------------------:|-------------------------:|-------------------------:|-----------------:|---------------------------------:|-------------------------:|--------------:|
|320 | 100 | 116 | **202** | 183 | 423 | **430** | **4.3x** |
|416 | 82 | 103 | **162** | 159 | 284 | **294** | **3.6x** |
|512 | 69 | 91 | 134 | **138** | 206 | **216** | **3.1x** |
|608 | 53 | 62 | 103 | **115** | 150 | **150** | **2.8x** |
|Tiny 416 | 443 | 609 | **790** | 773 | **1774** | 1353 | **3.5x** |
|Tiny 416 CPU Core i7 7700HQ | 3.4 | - | - | 42 | - | 39 | **12x** |

- Yolo v4 Full comparison: [map_fps](https://user-images.githubusercontent.com/4096485/80283279-0e303e00-871f-11ea-814c-870967d77fd1.png)
- Yolo v4 tiny comparison: [tiny_fps](https://user-images.githubusercontent.com/4096485/85734112-6e366700-b705-11ea-95d1-fcba0de76d72.png)
- CSPNet: [paper](https://arxiv.org/abs/1911.11929) and [map_fps](https://user-images.githubusercontent.com/4096485/71702416-6645dc00-2de0-11ea-8d65-de7d4b604021.png) comparison: https://github.com/WongKinYiu/CrossStagePartialNetworks
- Yolo v3 on MS COCO: [Speed / Accuracy ([email protected]) chart](https://user-images.githubusercontent.com/4096485/52151356-e5d4a380-2683-11e9-9d7d-ac7bc192c477.jpg)
- Yolo v3 on MS COCO (Yolo v3 vs RetinaNet) - Figure 3: https://arxiv.org/pdf/1804.02767v1.pdf
- Yolo v2 on Pascal VOC 2007: https://hsto.org/files/a24/21e/068/a2421e0689fb43f08584de9d44c2215f.jpg
- Yolo v2 on Pascal VOC 2012 (comp4): https://hsto.org/files/3a6/fdf/b53/3a6fdfb533f34cee9b52bdd9bb0b19d9.jpg

#### Youtube video of results

| [![Yolo v4](https://user-images.githubusercontent.com/4096485/101360000-1a33cf00-38ae-11eb-9e5e-b29c5fb0afbe.png)](https://youtu.be/1_SiUOYUoOI "Yolo v4") | [![Scaled Yolo v4](https://user-images.githubusercontent.com/4096485/101359389-43a02b00-38ad-11eb-866c-f813e96bf61a.png)](https://youtu.be/YDFf-TqJOFE "Scaled Yolo v4") |
|---|---|

Others: https://www.youtube.com/user/pjreddie/videos

#### How to evaluate AP of YOLOv4 on the MS COCO evaluation server

1. Download and unzip test-dev2017 dataset from MS COCO server: http://images.cocodataset.org/zips/test2017.zip
2. Download list of images for Detection tasks and replace the paths with yours: https://raw.githubusercontent.com/AlexeyAB/darknet/master/scripts/testdev2017.txt
3. Download `yolov4.weights` file 245 MB: [yolov4.weights](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v3_optimal/yolov4.weights) (Google-drive mirror [yolov4.weights](https://drive.google.com/open?id=1cewMfusmPjYWbrnuJRuKhPMwRe_b9PaT) )
4. Content of the file `cfg/coco.data` should be

```ini
classes= 80
train = /trainvalno5k.txt
valid = /testdev2017.txt
names = data/coco.names
backup = backup
eval=coco
```

5. Create `/results/` folder near with `./darknet` executable file
6. Run validation: `./darknet detector valid cfg/coco.data cfg/yolov4.cfg yolov4.weights`
7. Rename the file `/results/coco_results.json` to `detections_test-dev2017_yolov4_results.json` and compress it to `detections_test-dev2017_yolov4_results.zip`
8. Submit file `detections_test-dev2017_yolov4_results.zip` to the MS COCO evaluation server for the `test-dev2019 (bbox)`

#### How to evaluate FPS of YOLOv4 on GPU

1. Compile Darknet with `GPU=1 CUDNN=1 CUDNN_HALF=1 OPENCV=1` in the `Makefile`
2. Download `yolov4.weights` file 245 MB: [yolov4.weights](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v3_optimal/yolov4.weights) (Google-drive mirror [yolov4.weights](https://drive.google.com/open?id=1cewMfusmPjYWbrnuJRuKhPMwRe_b9PaT) )
3. Get any .avi/.mp4 video file (preferably not more than 1920x1080 to avoid bottlenecks in CPU performance)
4. Run one of two commands and look at the AVG FPS:

- include video_capturing + NMS + drawing_bboxes:
`./darknet detector demo cfg/coco.data cfg/yolov4.cfg yolov4.weights test.mp4 -dont_show -ext_output`
- exclude video_capturing + NMS + drawing_bboxes:
`./darknet detector demo cfg/coco.data cfg/yolov4.cfg yolov4.weights test.mp4 -benchmark`

#### Pre-trained models

There are weights-file for different cfg-files (trained for MS COCO dataset):

FPS on RTX 2070 (R) and Tesla V100 (V):

- [yolov4-p6.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov4-p6.cfg) - 1280x1280 - **72.1% [email protected] (54.0% [email protected]:0.95) - 32(V) FPS** - xxx BFlops (xxx FMA) - 487 MB: [yolov4-p6.weights](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-p6.weights)
- pre-trained weights for training: https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-p6.conv.289

- [yolov4-p5.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov4-p5.cfg) - 896x896 - **70.0% [email protected] (51.6% [email protected]:0.95) - 43(V) FPS** - xxx BFlops (xxx FMA) - 271 MB: [yolov4-p5.weights](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-p5.weights)
- pre-trained weights for training: https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-p5.conv.232

- [yolov4-csp-x-swish.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov4-csp-x-swish.cfg) - 640x640 - **69.9% [email protected] (51.5% [email protected]:0.95) - 23(R) FPS / 50(V) FPS** - 221 BFlops (110 FMA) - 381 MB: [yolov4-csp-x-swish.weights](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-csp-x-swish.weights)
- pre-trained weights for training: https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-csp-x-swish.conv.192

- [yolov4-csp-swish.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov4-csp-swish.cfg) - 640x640 - **68.7% [email protected] (50.0% [email protected]:0.95) - 70(V) FPS** - 120 (60 FMA) - 202 MB: [yolov4-csp-swish.weights](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-csp-swish.weights)
- pre-trained weights for training: https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-csp-swish.conv.164

- [yolov4x-mish.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov4x-mish.cfg) - 640x640 - **68.5% [email protected] (50.1% [email protected]:0.95) - 23(R) FPS / 50(V) FPS** - 221 BFlops (110 FMA) - 381 MB: [yolov4x-mish.weights](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4x-mish.weights)
- pre-trained weights for training: https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4x-mish.conv.166

- [yolov4-csp.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov4-csp.cfg) - 202 MB: [yolov4-csp.weights](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-csp.weights) paper [Scaled Yolo v4](https://arxiv.org/abs/2011.08036)

just change `width=` and `height=` parameters in `yolov4-csp.cfg` file and use the same `yolov4-csp.weights` file for all cases:
- `width=640 height=640` in cfg: **67.4% [email protected] (48.7% [email protected]:0.95) - 70(V) FPS** - 120 (60 FMA) BFlops
- `width=512 height=512` in cfg: **64.8% [email protected] (46.2% [email protected]:0.95) - 93(V) FPS** - 77 (39 FMA) BFlops
- pre-trained weights for training: https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-csp.conv.142

- [yolov4.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov4.cfg) - 245 MB: [yolov4.weights](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v3_optimal/yolov4.weights) (Google-drive mirror [yolov4.weights](https://drive.google.com/open?id=1cewMfusmPjYWbrnuJRuKhPMwRe_b9PaT) ) paper [Yolo v4](https://arxiv.org/abs/2004.10934)
just change `width=` and `height=` parameters in `yolov4.cfg` file and use the same `yolov4.weights` file for all cases:
- `width=608 height=608` in cfg: **65.7% [email protected] (43.5% [email protected]:0.95) - 34(R) FPS / 62(V) FPS** - 128.5 BFlops
- `width=512 height=512` in cfg: **64.9% [email protected] (43.0% [email protected]:0.95) - 45(R) FPS / 83(V) FPS** - 91.1 BFlops
- `width=416 height=416` in cfg: **62.8% [email protected] (41.2% [email protected]:0.95) - 55(R) FPS / 96(V) FPS** - 60.1 BFlops
- `width=320 height=320` in cfg: **60% [email protected] ( 38% [email protected]:0.95) - 63(R) FPS / 123(V) FPS** - 35.5 BFlops

- [yolov4-tiny.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov4-tiny.cfg) - **40.2% [email protected] - 371(1080Ti) FPS / 330(RTX2070) FPS** - 6.9 BFlops - 23.1 MB: [yolov4-tiny.weights](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-tiny.weights)

- [enet-coco.cfg (EfficientNetB0-Yolov3)](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/enet-coco.cfg) - **45.5% [email protected] - 55(R) FPS** - 3.7 BFlops - 18.3 MB: [enetb0-coco_final.weights](https://drive.google.com/file/d/1FlHeQjWEQVJt0ay1PVsiuuMzmtNyv36m/view)

- [yolov3-openimages.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov3-openimages.cfg) - 247 MB - 18(R) FPS - OpenImages dataset: [yolov3-openimages.weights](https://pjreddie.com/media/files/yolov3-openimages.weights)

CLICK ME - Yolo v3 models

- [csresnext50-panet-spp-original-optimal.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/csresnext50-panet-spp-original-optimal.cfg) - **65.4% [email protected] (43.2% [email protected]:0.95) - 32(R) FPS** - 100.5 BFlops - 217 MB: [csresnext50-panet-spp-original-optimal_final.weights](https://drive.google.com/open?id=1_NnfVgj0EDtb_WLNoXV8Mo7WKgwdYZCc)

- [yolov3-spp.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov3-spp.cfg) - **60.6% [email protected] - 38(R) FPS** - 141.5 BFlops - 240 MB: [yolov3-spp.weights](https://pjreddie.com/media/files/yolov3-spp.weights)

- [csresnext50-panet-spp.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/csresnext50-panet-spp.cfg) - **60.0% [email protected] - 44 FPS** - 71.3 BFlops - 217 MB: [csresnext50-panet-spp_final.weights](https://drive.google.com/file/d/1aNXdM8qVy11nqTcd2oaVB3mf7ckr258-/view?usp=sharing)

- [yolov3.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov3.cfg) - **55.3% [email protected] - 66(R) FPS** - 65.9 BFlops - 236 MB: [yolov3.weights](https://pjreddie.com/media/files/yolov3.weights)

- [yolov3-tiny.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov3-tiny.cfg) - **33.1% [email protected] - 345(R) FPS** - 5.6 BFlops - 33.7 MB: [yolov3-tiny.weights](https://pjreddie.com/media/files/yolov3-tiny.weights)

- [yolov3-tiny-prn.cfg](https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov3-tiny-prn.cfg) - **33.1% [email protected] - 370(R) FPS** - 3.5 BFlops - 18.8 MB: [yolov3-tiny-prn.weights](https://drive.google.com/file/d/18yYZWyKbo4XSDVyztmsEcF9B_6bxrhUY/view?usp=sharing)

CLICK ME - Yolo v2 models

- `yolov2.cfg` (194 MB COCO Yolo v2) - requires 4 GB GPU-RAM: https://pjreddie.com/media/files/yolov2.weights
- `yolo-voc.cfg` (194 MB VOC Yolo v2) - requires 4 GB GPU-RAM: http://pjreddie.com/media/files/yolo-voc.weights
- `yolov2-tiny.cfg` (43 MB COCO Yolo v2) - requires 1 GB GPU-RAM: https://pjreddie.com/media/files/yolov2-tiny.weights
- `yolov2-tiny-voc.cfg` (60 MB VOC Yolo v2) - requires 1 GB GPU-RAM: http://pjreddie.com/media/files/yolov2-tiny-voc.weights
- `yolo9000.cfg` (186 MB Yolo9000-model) - requires 4 GB GPU-RAM: http://pjreddie.com/media/files/yolo9000.weights

Put it near compiled: darknet.exe

You can get cfg-files by path: `darknet/cfg/`

### Requirements for Windows, Linux and macOS

- **CMake >= 3.18**: https://cmake.org/download/
- **Powershell** (already installed on windows): https://docs.microsoft.com/en-us/powershell/scripting/install/installing-powershell
- **CUDA >= 10.2**: https://developer.nvidia.com/cuda-toolkit-archive (on Linux do [Post-installation Actions](https://docs.nvidia.com/cuda/cuda-installation-guide-linux/index.html#post-installation-actions))
- **OpenCV >= 2.4**: use your preferred package manager (brew, apt), build from source using [vcpkg](https://github.com/Microsoft/vcpkg) or download from [OpenCV official site](https://opencv.org/releases.html) (on Windows set system variable `OpenCV_DIR` = `C:\opencv\build` - where are the `include` and `x64` folders [image](https://user-images.githubusercontent.com/4096485/53249516-5130f480-36c9-11e9-8238-a6e82e48c6f2.png))
- **cuDNN >= 8.0.2** https://developer.nvidia.com/rdp/cudnn-archive (on **Linux** follow steps described here https://docs.nvidia.com/deeplearning/sdk/cudnn-install/index.html#installlinux-tar , on **Windows** follow steps described here https://docs.nvidia.com/deeplearning/sdk/cudnn-install/index.html#installwindows)
- **GPU with CC >= 3.0**: https://en.wikipedia.org/wiki/CUDA#GPUs_supported

### Yolo v4 in other frameworks

- **Pytorch - Scaled-YOLOv4:** https://github.com/WongKinYiu/ScaledYOLOv4
- **TensorFlow:** `pip install yolov4` YOLOv4 on TensorFlow 2.0 / TFlite / Android: https://github.com/hunglc007/tensorflow-yolov4-tflite
Official TF models: https://github.com/tensorflow/models/tree/master/official/vision/beta/projects/yolo
For YOLOv4 - convert `yolov4.weights`/`cfg` files to `yolov4.pb` by using [TNTWEN](https://github.com/TNTWEN/OpenVINO-YOLOV4) project, and to `yolov4.tflite` [TensorFlow-lite](https://www.tensorflow.org/lite/guide/get_started#2_convert_the_model_format)
- **OpenCV** the fastest implementation of YOLOv4 for CPU (x86/ARM-Android), OpenCV can be compiled with [OpenVINO-backend](https://github.com/opencv/opencv/wiki/Intel's-Deep-Learning-Inference-Engine-backend) for running on (Myriad X / USB Neural Compute Stick / Arria FPGA), use `yolov4.weights`/`cfg` with: [C++ example](https://github.com/opencv/opencv/blob/8c25a8eb7b10fb50cda323ee6bec68aa1a9ce43c/samples/dnn/object_detection.cpp#L192-L221) or [Python example](https://github.com/opencv/opencv/blob/8c25a8eb7b10fb50cda323ee6bec68aa1a9ce43c/samples/dnn/object_detection.py#L129-L150)
- **Intel OpenVINO 2021.2:** supports YOLOv4 (NPU Myriad X / USB Neural Compute Stick / Arria FPGA): https://devmesh.intel.com/projects/openvino-yolov4-49c756 read this [manual](https://github.com/TNTWEN/OpenVINO-YOLOV4) (old [manual](https://software.intel.com/en-us/articles/OpenVINO-Using-TensorFlow#converting-a-darknet-yolo-model) ) (for [Scaled-YOLOv4](https://github.com/WongKinYiu/ScaledYOLOv4/tree/yolov4-large) models use https://github.com/Chen-MingChang/pytorch_YOLO_OpenVINO_demo )
- **PyTorch > ONNX**:
- [WongKinYiu/PyTorch_YOLOv4](https://github.com/WongKinYiu/PyTorch_YOLOv4)
- [maudzung/3D-YOLOv4](https://github.com/maudzung/Complex-YOLOv4-Pytorch)
- [Tianxiaomo/pytorch-YOLOv4](https://github.com/Tianxiaomo/pytorch-YOLOv4)
- [YOLOv5](https://github.com/ultralytics/yolov5)
- **ONNX** on Jetson for YOLOv4: https://developer.nvidia.com/blog/announcing-onnx-runtime-for-jetson/ and https://github.com/ttanzhiqiang/onnx_tensorrt_project
- **nVidia Transfer Learning Toolkit (TLT>=3.0)** Training and Detection https://docs.nvidia.com/metropolis/TLT/tlt-user-guide/text/object_detection/yolo_v4.html
- **TensorRT+tkDNN**: https://github.com/ceccocats/tkDNN#fps-results
- **Deepstream 5.0 / TensorRT for YOLOv4** https://github.com/NVIDIA-AI-IOT/yolov4_deepstream or https://github.com/marcoslucianops/DeepStream-Yolo read [Yolo is natively supported in DeepStream 4.0](https://news.developer.nvidia.com/deepstream-sdk-4-now-available/) and [PDF](https://docs.nvidia.com/metropolis/deepstream/Custom_YOLO_Model_in_the_DeepStream_YOLO_App.pdf). Additionally [jkjung-avt/tensorrt_demos](https://github.com/jkjung-avt/tensorrt_demos) or [wang-xinyu/tensorrtx](https://github.com/wang-xinyu/tensorrtx)
- **Triton Inference Server / TensorRT** https://github.com/isarsoft/yolov4-triton-tensorrt
- **DirectML** https://github.com/microsoft/DirectML/tree/master/Samples/yolov4
- **OpenCL** (Intel, AMD, Mali GPUs for macOS & GNU/Linux) https://github.com/sowson/darknet
- **HIP** for Training and Detection on AMD GPU https://github.com/os-hackathon/darknet
- **ROS** (Robot Operating System) https://github.com/engcang/ros-yolo-sort
- **Xilinx Zynq Ultrascale+ Deep Learning Processor (DPU) ZCU102/ZCU104:** https://github.com/Xilinx/Vitis-In-Depth-Tutorial/tree/master/Machine_Learning/Design_Tutorials/07-yolov4-tutorial
- **Amazon Neurochip / Amazon EC2 Inf1 instances** 1.85 times higher throughput and 37% lower cost per image for TensorFlow based YOLOv4 model, using Keras [URL](https://aws.amazon.com/ru/blogs/machine-learning/improving-performance-for-deep-learning-based-object-detection-with-an-aws-neuron-compiled-yolov4-model-on-aws-inferentia/)
- **TVM** - compilation of deep learning models (Keras, MXNet, PyTorch, Tensorflow, CoreML, DarkNet) into minimum deployable modules on diverse hardware backend (CPUs, GPUs, FPGA, and specialized accelerators): https://tvm.ai/about
- **Tencent/ncnn:** the fastest inference of YOLOv4 on mobile phone CPU: https://github.com/Tencent/ncnn
- **OpenDataCam** - It detects, tracks and counts moving objects by using YOLOv4: https://github.com/opendatacam/opendatacam#-hardware-pre-requisite
- **Netron** - Visualizer for neural networks: https://github.com/lutzroeder/netron

#### Datasets

- MS COCO: use `./scripts/get_coco_dataset.sh` to get labeled MS COCO detection dataset
- OpenImages: use `python ./scripts/get_openimages_dataset.py` for labeling train detection dataset
- Pascal VOC: use `python ./scripts/voc_label.py` for labeling Train/Test/Val detection datasets
- ILSVRC2012 (ImageNet classification): use `./scripts/get_imagenet_train.sh` (also `imagenet_label.sh` for labeling valid set)
- German/Belgium/Russian/LISA/MASTIF Traffic Sign Datasets for Detection - use this parser: https://github.com/angeligareta/Datasets2Darknet#detection-task
- List of other datasets: https://github.com/AlexeyAB/darknet/tree/master/scripts#datasets

### Improvements in this repository

- developed State-of-the-Art object detector YOLOv4
- added State-of-Art models: CSP, PRN, EfficientNet
- added layers: [conv_lstm], [scale_channels] SE/ASFF/BiFPN, [local_avgpool], [sam], [Gaussian_yolo], [reorg3d] (fixed [reorg]), fixed [batchnorm]
- added the ability for training recurrent models (with layers conv-lstm`[conv_lstm]`/conv-rnn`[crnn]`) for accurate detection on video
- added data augmentation: `[net] mixup=1 cutmix=1 mosaic=1 blur=1`. Added activations: SWISH, MISH, NORM_CHAN, NORM_CHAN_SOFTMAX
- added the ability for training with GPU-processing using CPU-RAM to increase the mini_batch_size and increase accuracy (instead of batch-norm sync)
- improved binary neural network performance **2x-4x times** for Detection on CPU and GPU if you trained your own weights by using this XNOR-net model (bit-1 inference) : https://github.com/AlexeyAB/darknet/blob/master/cfg/yolov3-tiny_xnor.cfg
- improved neural network performance **~7%** by fusing 2 layers into 1: Convolutional + Batch-norm
- improved performance: Detection **2x times**, on GPU Volta/Turing (Tesla V100, GeForce RTX, ...) using Tensor Cores if `CUDNN_HALF` defined in the `Makefile` or `darknet.sln`
- improved performance **~1.2x** times on FullHD, **~2x** times on 4K, for detection on the video (file/stream) using `darknet detector demo`...
- improved performance **3.5 X times** of data augmentation for training (using OpenCV SSE/AVX functions instead of hand-written functions) - removes bottleneck for training on multi-GPU or GPU Volta
- improved performance of detection and training on Intel CPU with AVX (Yolo v3 **~85%**)
- optimized memory allocation during network resizing when `random=1`
- optimized GPU initialization for detection - we use batch=1 initially instead of re-init with batch=1
- added correct calculation of **mAP, F1, IoU, Precision-Recall** using command `darknet detector map`...
- added drawing of chart of average-Loss and accuracy-mAP (`-map` flag) during training
- run `./darknet detector demo ... -json_port 8070 -mjpeg_port 8090` as JSON and MJPEG server to get results online over the network by using your soft or Web-browser
- added calculation of anchors for training
- added example of Detection and Tracking objects: https://github.com/AlexeyAB/darknet/blob/master/src/yolo_console_dll.cpp
- run-time tips and warnings if you use incorrect cfg-file or dataset
- added support for Windows
- many other fixes of code...

And added manual - [How to train Yolo v4-v2 (to detect your custom objects)](#how-to-train-to-detect-your-custom-objects)

Also, you might be interested in using a simplified repository where is implemented INT8-quantization (+30% speedup and -1% mAP reduced): https://github.com/AlexeyAB/yolo2_light

#### How to use on the command line

If you use `build.ps1` script or the makefile (Linux only) you will find `darknet` in the root directory.

If you use the deprecated Visual Studio solutions, you will find `darknet` in the directory `\build\darknet\x64`.

If you customize build with CMake GUI, darknet executable will be installed in your preferred folder.

- Yolo v4 COCO - **image**: `./darknet detector test cfg/coco.data cfg/yolov4.cfg yolov4.weights -thresh 0.25`
- **Output coordinates** of objects: `./darknet detector test cfg/coco.data yolov4.cfg yolov4.weights -ext_output dog.jpg`
- Yolo v4 COCO - **video**: `./darknet detector demo cfg/coco.data cfg/yolov4.cfg yolov4.weights -ext_output test.mp4`
- Yolo v4 COCO - **WebCam 0**: `./darknet detector demo cfg/coco.data cfg/yolov4.cfg yolov4.weights -c 0`
- Yolo v4 COCO for **net-videocam** - Smart WebCam: `./darknet detector demo cfg/coco.data cfg/yolov4.cfg yolov4.weights http://192.168.0.80:8080/video?dummy=param.mjpg`
- Yolo v4 - **save result videofile res.avi**: `./darknet detector demo cfg/coco.data cfg/yolov4.cfg yolov4.weights test.mp4 -out_filename res.avi`
- Yolo v3 **Tiny** COCO - video: `./darknet detector demo cfg/coco.data cfg/yolov3-tiny.cfg yolov3-tiny.weights test.mp4`
- **JSON and MJPEG server** that allows multiple connections from your soft or Web-browser `ip-address:8070` and 8090: `./darknet detector demo ./cfg/coco.data ./cfg/yolov3.cfg ./yolov3.weights test50.mp4 -json_port 8070 -mjpeg_port 8090 -ext_output`
- Yolo v3 Tiny **on GPU #1**: `./darknet detector demo cfg/coco.data cfg/yolov3-tiny.cfg yolov3-tiny.weights -i 1 test.mp4`
- Alternative method Yolo v3 COCO - image: `./darknet detect cfg/yolov4.cfg yolov4.weights -i 0 -thresh 0.25`
- Train on **Amazon EC2**, to see mAP & Loss-chart using URL like: `http://ec2-35-160-228-91.us-west-2.compute.amazonaws.com:8090` in the Chrome/Firefox (**Darknet should be compiled with OpenCV**):
`./darknet detector train cfg/coco.data yolov4.cfg yolov4.conv.137 -dont_show -mjpeg_port 8090 -map`
- 186 MB Yolo9000 - image: `./darknet detector test cfg/combine9k.data cfg/yolo9000.cfg yolo9000.weights`
- Remember to put data/9k.tree and data/coco9k.map under the same folder of your app if you use the cpp api to build an app
- To process a list of images `data/train.txt` and save results of detection to `result.json` file use:
`./darknet detector test cfg/coco.data cfg/yolov4.cfg yolov4.weights -ext_output -dont_show -out result.json < data/train.txt`
- To process a list of images `data/train.txt` and save results of detection to `result.txt` use:
`./darknet detector test cfg/coco.data cfg/yolov4.cfg yolov4.weights -dont_show -ext_output < data/train.txt > result.txt`
- To process a video and output results to a json file use: `darknet.exe detector demo cfg/coco.data cfg/yolov3.cfg yolov3.weights file.mp4 -dont_show -json_file_output results.json`
- Pseudo-labelling - to process a list of images `data/new_train.txt` and save results of detection in Yolo training format for each image as label `.txt` (in this way you can increase the amount of training data) use:
`./darknet detector test cfg/coco.data cfg/yolov4.cfg yolov4.weights -thresh 0.25 -dont_show -save_labels < data/new_train.txt`
- To calculate anchors: `./darknet detector calc_anchors data/obj.data -num_of_clusters 9 -width 416 -height 416`
- To check accuracy mAP@IoU=50: `./darknet detector map data/obj.data yolo-obj.cfg backup\yolo-obj_7000.weights`
- To check accuracy mAP@IoU=75: `./darknet detector map data/obj.data yolo-obj.cfg backup\yolo-obj_7000.weights -iou_thresh 0.75`

##### For using network video-camera mjpeg-stream with any Android smartphone

1. Download for Android phone mjpeg-stream soft: IP Webcam / Smart WebCam

- Smart WebCam - preferably: https://play.google.com/store/apps/details?id=com.acontech.android.SmartWebCam2
- IP Webcam: https://play.google.com/store/apps/details?id=com.pas.webcam

2. Connect your Android phone to the computer by WiFi (through a WiFi-router) or USB
3. Start Smart WebCam on your phone
4. Replace the address below, shown in the phone application (Smart WebCam) and launch:

- Yolo v4 COCO-model: `./darknet detector demo data/coco.data yolov4.cfg yolov4.weights http://192.168.0.80:8080/video?dummy=param.mjpg -i 0`

### How to compile on Linux/macOS (using `CMake`)

The `CMakeLists.txt` will attempt to find installed optional dependencies like CUDA, cudnn, ZED and build against those. It will also create a shared object library file to use `darknet` for code development.

To update CMake on Ubuntu, it's better to follow guide here: https://apt.kitware.com/ or https://cmake.org/download/

```bash
git clone https://github.com/AlexeyAB/darknet
cd darknet
mkdir build_release
cd build_release
cmake ..
cmake --build . --target install --parallel 8
```

### Using also PowerShell

Install: `Cmake`, `CUDA`, `cuDNN` [How to install dependencies](#requirements)

Install powershell for your OS (Linux or MacOS) ([guide here](https://docs.microsoft.com/en-us/powershell/scripting/install/installing-powershell)).

Open PowerShell type these commands

```PowerShell
git clone https://github.com/AlexeyAB/darknet
cd darknet
./build.ps1 -UseVCPKG -EnableOPENCV -EnableCUDA -EnableCUDNN
```

- remove options like `-EnableCUDA` or `-EnableCUDNN` if you are not interested into
- remove option `-UseVCPKG` if you plan to manually provide OpenCV library to darknet or if you do not want to enable OpenCV integration
- add option `-EnableOPENCV_CUDA` if you want to build OpenCV with CUDA support - very slow to build! (requires `-UseVCPKG`)

If you open the `build.ps1` script at the beginning you will find all available switches.

### How to compile on Linux (using `make`)

Just do `make` in the darknet directory. (You can try to compile and run it on Google Colab in cloud [link](https://colab.research.google.com/drive/12QusaaRj_lUwCGDvQNfICpa7kA7_a2dE) (press «Open in Playground» button at the top-left corner) and watch the video [link](https://www.youtube.com/watch?v=mKAEGSxwOAY) )
Before make, you can set such options in the `Makefile`: [link](https://github.com/AlexeyAB/darknet/blob/9c1b9a2cf6363546c152251be578a21f3c3caec6/Makefile#L1)

- `GPU=1` to build with CUDA to accelerate by using GPU (CUDA should be in `/usr/local/cuda`)
- `CUDNN=1` to build with cuDNN v5-v7 to accelerate training by using GPU (cuDNN should be in `/usr/local/cudnn`)
- `CUDNN_HALF=1` to build for Tensor Cores (on Titan V / Tesla V100 / DGX-2 and later) speedup Detection 3x, Training 2x
- `OPENCV=1` to build with OpenCV 4.x/3.x/2.4.x - allows to detect on video files and video streams from network cameras or web-cams
- `DEBUG=1` to build debug version of Yolo
- `OPENMP=1` to build with OpenMP support to accelerate Yolo by using multi-core CPU
- `LIBSO=1` to build a library `darknet.so` and binary runnable file `uselib` that uses this library. Or you can try to run so `LD_LIBRARY_PATH=./:$LD_LIBRARY_PATH ./uselib test.mp4` How to use this SO-library from your own code - you can look at C++ example: https://github.com/AlexeyAB/darknet/blob/master/src/yolo_console_dll.cpp
or use in such a way: `LD_LIBRARY_PATH=./:$LD_LIBRARY_PATH ./uselib data/coco.names cfg/yolov4.cfg yolov4.weights test.mp4`
- `ZED_CAMERA=1` to build a library with ZED-3D-camera support (should be ZED SDK installed), then run
`LD_LIBRARY_PATH=./:$LD_LIBRARY_PATH ./uselib data/coco.names cfg/yolov4.cfg yolov4.weights zed_camera`
- You also need to specify for which graphics card the code is generated. This is done by setting `ARCH=`. If you use a newer version than CUDA 11 you further need to edit line 20 from Makefile and remove `-gencode arch=compute_30,code=sm_30 \` as Kepler GPU support was dropped in CUDA 11. You can also drop the general `ARCH=` and just uncomment `ARCH=` for your graphics card.

### How to compile on Windows (using `CMake`)

Requires:

- MSVC: https://visualstudio.microsoft.com/thank-you-downloading-visual-studio/?sku=Community
- CMake GUI: `Windows win64-x64 Installer`https://cmake.org/download/
- Download Darknet zip-archive with the latest commit and uncompress it: [master.zip](https://github.com/AlexeyAB/darknet/archive/master.zip)

In Windows:

- Start (button) -> All programs -> CMake -> CMake (gui) ->

- [look at image](https://habrastorage.org/webt/pz/s1/uu/pzs1uu4heb7vflfcjqn-lxy-aqu.jpeg) In CMake: Enter input path to the darknet Source, and output path to the Binaries -> Configure (button) -> Optional platform for generator: `x64` -> Finish -> Generate -> Open Project ->

- in MS Visual Studio: Select: x64 and Release -> Build -> Build solution

- find the executable file `darknet.exe` in the output path to the binaries you specified

![x64 and Release](https://habrastorage.org/webt/ay/ty/f-/aytyf-8bufe7q-16yoecommlwys.jpeg)

### How to compile on Windows (using `vcpkg`)

This is the recommended approach to build Darknet on Windows.

1. Install Visual Studio 2017 or 2019. In case you need to download it, please go here: [Visual Studio Community](http://visualstudio.com). Remember to install English language pack, this is mandatory for vcpkg!

2. Install CUDA enabling VS Integration during installation.

3. Open Powershell (Start -> All programs -> Windows Powershell) and type these commands:

```PowerShell
Set-ExecutionPolicy unrestricted -Scope CurrentUser -Force
git clone https://github.com/AlexeyAB/darknet
cd darknet
.\build.ps1 -UseVCPKG -EnableOPENCV -EnableCUDA -EnableCUDNN
```

(add option `-EnableOPENCV_CUDA` if you want to build OpenCV with CUDA support - very slow to build! - or remove options like `-EnableCUDA` or `-EnableCUDNN` if you are not interested in them). If you open the `build.ps1` script at the beginning you will find all available switches.

## How to train with multi-GPU

1. Train it first on 1 GPU for like 1000 iterations: `darknet.exe detector train cfg/coco.data cfg/yolov4.cfg yolov4.conv.137`

2. Then stop and by using partially-trained model `/backup/yolov4_1000.weights` run training with multigpu (up to 4 GPUs): `darknet.exe detector train cfg/coco.data cfg/yolov4.cfg /backup/yolov4_1000.weights -gpus 0,1,2,3`

If you get a Nan, then for some datasets better to decrease learning rate, for 4 GPUs set `learning_rate = 0,00065` (i.e. learning_rate = 0.00261 / GPUs). In this case also increase 4x times `burn_in =` in your cfg-file. I.e. use `burn_in = 4000` instead of `1000`.

https://groups.google.com/d/msg/darknet/NbJqonJBTSY/Te5PfIpuCAAJ

## How to train (to detect your custom objects)

(to train old Yolo v2 `yolov2-voc.cfg`, `yolov2-tiny-voc.cfg`, `yolo-voc.cfg`, `yolo-voc.2.0.cfg`, ... [click by the link](https://github.com/AlexeyAB/darknet/tree/47c7af1cea5bbdedf1184963355e6418cb8b1b4f#how-to-train-pascal-voc-data))

Training Yolo v4 (and v3):

0. For training `cfg/yolov4-custom.cfg` download the pre-trained weights-file (162 MB): [yolov4.conv.137](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v3_optimal/yolov4.conv.137) (Google drive mirror [yolov4.conv.137](https://drive.google.com/open?id=1JKF-bdIklxOOVy-2Cr5qdvjgGpmGfcbp) )
1. Create file `yolo-obj.cfg` with the same content as in `yolov4-custom.cfg` (or copy `yolov4-custom.cfg` to `yolo-obj.cfg)` and:

- change line batch to [`batch=64`](https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L3)
- change line subdivisions to [`subdivisions=16`](https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L4)
- change line max_batches to (`classes*2000`, but not less than number of training images and not less than `6000`), f.e. [`max_batches=6000`](https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L20) if you train for 3 classes
- change line steps to 80% and 90% of max_batches, f.e. [`steps=4800,5400`](https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L22)
- set network size `width=416 height=416` or any value multiple of 32: https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L8-L9
- change line `classes=80` to your number of objects in each of 3 `[yolo]`-layers:
- https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L610
- https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L696
- https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L783
- change [`filters=255`] to filters=(classes + 5)x3 in the 3 `[convolutional]` before each `[yolo]` layer, keep in mind that it only has to be the last `[convolutional]` before each of the `[yolo]` layers.
- https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L603
- https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L689
- https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L776
- when using [`[Gaussian_yolo]`](https://github.com/AlexeyAB/darknet/blob/6e5bdf1282ad6b06ed0e962c3f5be67cf63d96dc/cfg/Gaussian_yolov3_BDD.cfg#L608) layers, change [`filters=57`] filters=(classes + 9)x3 in the 3 `[convolutional]` before each `[Gaussian_yolo]` layer
- https://github.com/AlexeyAB/darknet/blob/6e5bdf1282ad6b06ed0e962c3f5be67cf63d96dc/cfg/Gaussian_yolov3_BDD.cfg#L604
- https://github.com/AlexeyAB/darknet/blob/6e5bdf1282ad6b06ed0e962c3f5be67cf63d96dc/cfg/Gaussian_yolov3_BDD.cfg#L696
- https://github.com/AlexeyAB/darknet/blob/6e5bdf1282ad6b06ed0e962c3f5be67cf63d96dc/cfg/Gaussian_yolov3_BDD.cfg#L789

So if `classes=1` then should be `filters=18`. If `classes=2` then write `filters=21`.
**(Do not write in the cfg-file: filters=(classes + 5)x3)**

(Generally `filters` depends on the `classes`, `coords` and number of `mask`s, i.e. filters=`(classes + coords + 1)*`, where `mask` is indices of anchors. If `mask` is absence, then filters=`(classes + coords + 1)*num`)

So for example, for 2 objects, your file `yolo-obj.cfg` should differ from `yolov4-custom.cfg` in such lines in each of **3** [yolo]-layers:

```ini
[convolutional]
filters=21

[region]
classes=2
```

2. Create file `obj.names` in the directory `build\darknet\x64\data\`, with objects names - each in new line
3. Create file `obj.data` in the directory `build\darknet\x64\data\`, containing (where **classes = number of objects**):

```ini
classes = 2
train = data/train.txt
valid = data/test.txt
names = data/obj.names
backup = backup/
```

4. Put image-files (.jpg) of your objects in the directory `build\darknet\x64\data\obj\`
5. You should label each object on images from your dataset. Use this visual GUI-software for marking bounded boxes of objects and generating annotation files for Yolo v2 & v3: https://github.com/AlexeyAB/Yolo_mark

It will create `.txt`-file for each `.jpg`-image-file - in the same directory and with the same name, but with `.txt`-extension, and put to file: object number and object coordinates on this image, for each object in new line:

` `

Where:

- `` - integer object number from `0` to `(classes-1)`
- ` ` - float values **relative** to width and height of image, it can be equal from `(0.0 to 1.0]`
- for example: ` = / ` or ` = / `
- attention: ` ` - are center of rectangle (are not top-left corner)

For example for `img1.jpg` you will be created `img1.txt` containing:

```csv
1 0.716797 0.395833 0.216406 0.147222
0 0.687109 0.379167 0.255469 0.158333
1 0.420312 0.395833 0.140625 0.166667
```

6. Create file `train.txt` in directory `build\darknet\x64\data\`, with filenames of your images, each filename in new line, with path relative to `darknet.exe`, for example containing:

```csv
data/obj/img1.jpg
data/obj/img2.jpg
data/obj/img3.jpg
```

7. Download pre-trained weights for the convolutional layers and put to the directory `build\darknet\x64`
- for `yolov4.cfg`, `yolov4-custom.cfg` (162 MB): [yolov4.conv.137](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v3_optimal/yolov4.conv.137) (Google drive mirror [yolov4.conv.137](https://drive.google.com/open?id=1JKF-bdIklxOOVy-2Cr5qdvjgGpmGfcbp) )
- for `yolov4-tiny.cfg`, `yolov4-tiny-3l.cfg`, `yolov4-tiny-custom.cfg` (19 MB): [yolov4-tiny.conv.29](https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-tiny.conv.29)
- for `csresnext50-panet-spp.cfg` (133 MB): [csresnext50-panet-spp.conv.112](https://drive.google.com/file/d/16yMYCLQTY_oDlCIZPfn_sab6KD3zgzGq/view?usp=sharing)
- for `yolov3.cfg, yolov3-spp.cfg` (154 MB): [darknet53.conv.74](https://pjreddie.com/media/files/darknet53.conv.74)
- for `yolov3-tiny-prn.cfg , yolov3-tiny.cfg` (6 MB): [yolov3-tiny.conv.11](https://drive.google.com/file/d/18v36esoXCh-PsOKwyP2GWrpYDptDY8Zf/view?usp=sharing)
- for `enet-coco.cfg (EfficientNetB0-Yolov3)` (14 MB): [enetb0-coco.conv.132](https://drive.google.com/file/d/1uhh3D6RSn0ekgmsaTcl-ZW53WBaUDo6j/view?usp=sharing)

8. Start training by using the command line: `darknet.exe detector train data/obj.data yolo-obj.cfg yolov4.conv.137`

To train on Linux use command: `./darknet detector train data/obj.data yolo-obj.cfg yolov4.conv.137` (just use `./darknet` instead of `darknet.exe`)

- (file `yolo-obj_last.weights` will be saved to the `build\darknet\x64\backup\` for each 100 iterations)
- (file `yolo-obj_xxxx.weights` will be saved to the `build\darknet\x64\backup\` for each 1000 iterations)
- (to disable Loss-Window use `darknet.exe detector train data/obj.data yolo-obj.cfg yolov4.conv.137 -dont_show`, if you train on computer without monitor like a cloud Amazon EC2)
- (to see the mAP & Loss-chart during training on remote server without GUI, use command `darknet.exe detector train data/obj.data yolo-obj.cfg yolov4.conv.137 -dont_show -mjpeg_port 8090 -map` then open URL `http://ip-address:8090` in Chrome/Firefox browser)

8.1. For training with mAP (mean average precisions) calculation for each 4 Epochs (set `valid=valid.txt` or `train.txt` in `obj.data` file) and run: `darknet.exe detector train data/obj.data yolo-obj.cfg yolov4.conv.137 -map`

8.2. One can also set the `-mAP_epochs` in the training command if less or more frequent mAP calculation is needed. For example in order to calculate mAP for each 2 Epochs run `darknet.exe detector train data/obj.data yolo-obj.cfg yolov4.conv.137 -map -mAP_epochs 2`

9. After training is complete - get result `yolo-obj_final.weights` from path `build\darknet\x64\backup\`

- After each 100 iterations you can stop and later start training from this point. For example, after 2000 iterations you can stop training, and later just start training using: `darknet.exe detector train data/obj.data yolo-obj.cfg backup\yolo-obj_2000.weights`

(in the original repository https://github.com/pjreddie/darknet the weights-file is saved only once every 10 000 iterations `if(iterations > 1000)`)

- Also you can get result earlier than all 45000 iterations.

**Note:** If during training you see `nan` values for `avg` (loss) field - then training goes wrong, but if `nan` is in some other lines - then training goes well.

**Note:** If you changed width= or height= in your cfg-file, then new width and height must be divisible by 32.

**Note:** After training use such command for detection: `darknet.exe detector test data/obj.data yolo-obj.cfg yolo-obj_8000.weights`

**Note:** if error `Out of memory` occurs then in `.cfg`-file you should increase `subdivisions=16`, 32 or 64: [link](https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L4)

### How to train tiny-yolo (to detect your custom objects)

Do all the same steps as for the full yolo model as described above. With the exception of:

- Download file with the first 29-convolutional layers of yolov4-tiny: https://github.com/AlexeyAB/darknet/releases/download/darknet_yolo_v4_pre/yolov4-tiny.conv.29
(Or get this file from yolov4-tiny.weights file by using command: `darknet.exe partial cfg/yolov4-tiny-custom.cfg yolov4-tiny.weights yolov4-tiny.conv.29 29`
- Make your custom model `yolov4-tiny-obj.cfg` based on `cfg/yolov4-tiny-custom.cfg` instead of `yolov4.cfg`
- Start training: `darknet.exe detector train data/obj.data yolov4-tiny-obj.cfg yolov4-tiny.conv.29`

For training Yolo based on other models ([DenseNet201-Yolo](https://github.com/AlexeyAB/darknet/blob/master/build/darknet/x64/densenet201_yolo.cfg) or [ResNet50-Yolo](https://github.com/AlexeyAB/darknet/blob/master/build/darknet/x64/resnet50_yolo.cfg)), you can download and get pre-trained weights as showed in this file: https://github.com/AlexeyAB/darknet/blob/master/build/darknet/x64/partial.cmd
If you made you custom model that isn't based on other models, then you can train it without pre-trained weights, then will be used random initial weights.

## When should I stop training

Usually sufficient 2000 iterations for each class(object), but not less than number of training images and not less than 6000 iterations in total. But for a more precise definition of when you should stop training, use the following manual:

1. During training, you will see varying indicators of error, and you should stop when no longer decreases **0.XXXXXXX avg**:

> Region Avg IOU: 0.798363, Class: 0.893232, Obj: 0.700808, No Obj: 0.004567, Avg Recall: 1.000000, count: 8
> Region Avg IOU: 0.800677, Class: 0.892181, Obj: 0.701590, No Obj: 0.004574, Avg Recall: 1.000000, count: 8
>
> **9002**: 0.211667, **0.60730 avg**, 0.001000 rate, 3.868000 seconds, 576128 images
> Loaded: 0.000000 seconds

- **9002** - iteration number (number of batch)
- **0.60730 avg** - average loss (error) - **the lower, the better**

When you see that average loss **0.xxxxxx avg** no longer decreases at many iterations then you should stop training. The final average loss can be from `0.05` (for a small model and easy dataset) to `3.0` (for a big model and a difficult dataset).

Or if you train with flag `-map` then you will see mAP indicator `Last accuracy [email protected] = 18.50%` in the console - this indicator is better than Loss, so train while mAP increases.

2. Once training is stopped, you should take some of last `.weights`-files from `darknet\build\darknet\x64\backup` and choose the best of them:

For example, you stopped training after 9000 iterations, but the best result can give one of previous weights (7000, 8000, 9000). It can happen due to over-fitting. **Over-fitting** - is case when you can detect objects on images from training-dataset, but can't detect objects on any others images. You should get weights from **Early Stopping Point**:

![Over-fitting](https://hsto.org/files/5dc/7ae/7fa/5dc7ae7fad9d4e3eb3a484c58bfc1ff5.png)

To get weights from Early Stopping Point:

2.1. At first, in your file `obj.data` you must specify the path to the validation dataset `valid = valid.txt` (format of `valid.txt` as in `train.txt`), and if you haven't validation images, just copy `data\train.txt` to `data\valid.txt`.

2.2 If training is stopped after 9000 iterations, to validate some of previous weights use this commands:

(If you use another GitHub repository, then use `darknet.exe detector recall`... instead of `darknet.exe detector map`...)

- `darknet.exe detector map data/obj.data yolo-obj.cfg backup\yolo-obj_7000.weights`
- `darknet.exe detector map data/obj.data yolo-obj.cfg backup\yolo-obj_8000.weights`
- `darknet.exe detector map data/obj.data yolo-obj.cfg backup\yolo-obj_9000.weights`

And compare last output lines for each weights (7000, 8000, 9000):

Choose weights-file **with the highest mAP (mean average precision)** or IoU (intersect over union)

For example, **bigger mAP** gives weights `yolo-obj_8000.weights` - then **use this weights for detection**.

Or just train with `-map` flag:

`darknet.exe detector train data/obj.data yolo-obj.cfg yolov4.conv.137 -map`

So you will see mAP-chart (red-line) in the Loss-chart Window. mAP will be calculated for each 4 Epochs using `valid=valid.txt` file that is specified in `obj.data` file (`1 Epoch = images_in_train_txt / batch` iterations)

(to change the max x-axis value - change [`max_batches=`](https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L20) parameter to `2000*classes`, f.e. `max_batches=6000` for 3 classes)

![loss_chart_map_chart](https://hsto.org/webt/yd/vl/ag/ydvlagutof2zcnjodstgroen8ac.jpeg)

Example of custom object detection: `darknet.exe detector test data/obj.data yolo-obj.cfg yolo-obj_8000.weights`

- **IoU** (intersect over union) - average intersect over union of objects and detections for a certain threshold = 0.24

- **mAP** (mean average precision) - mean value of `average precisions` for each class, where `average precision` is average value of 11 points on PR-curve for each possible threshold (each probability of detection) for the same class (Precision-Recall in terms of PascalVOC, where Precision=TP/(TP+FP) and Recall=TP/(TP+FN) ), page-11: http://homepages.inf.ed.ac.uk/ckiw/postscript/ijcv_voc09.pdf

**mAP** is default metric of precision in the PascalVOC competition, **this is the same as AP50** metric in the MS COCO competition.
In terms of Wiki, indicators Precision and Recall have a slightly different meaning than in the PascalVOC competition, but **IoU always has the same meaning**.

![precision_recall_iou](https://hsto.org/files/ca8/866/d76/ca8866d76fb840228940dbf442a7f06a.jpg)

### Custom object detection

Example of custom object detection: `darknet.exe detector test data/obj.data yolo-obj.cfg yolo-obj_8000.weights`

| ![Yolo_v2_training](https://hsto.org/files/d12/1e7/515/d121e7515f6a4eb694913f10de5f2b61.jpg) | ![Yolo_v2_training](https://hsto.org/files/727/c7e/5e9/727c7e5e99bf4d4aa34027bb6a5e4bab.jpg) |
|---|---|

## How to improve object detection

1. Before training:

- set flag `random=1` in your `.cfg`-file - it will increase precision by training Yolo for different resolutions: [link](https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L788)

- increase network resolution in your `.cfg`-file (`height=608`, `width=608` or any value multiple of 32) - it will increase precision

- check that each object that you want to detect is mandatory labeled in your dataset - no one object in your data set should not be without label. In the most training issues - there are wrong labels in your dataset (got labels by using some conversion script, marked with a third-party tool, ...). Always check your dataset by using: https://github.com/AlexeyAB/Yolo_mark

- my Loss is very high and mAP is very low, is training wrong? Run training with `-show_imgs` flag at the end of training command, do you see correct bounded boxes of objects (in windows or in files `aug_...jpg`)? If no - your training dataset is wrong.

- for each object which you want to detect - there must be at least 1 similar object in the Training dataset with about the same: shape, side of object, relative size, angle of rotation, tilt, illumination. So desirable that your training dataset include images with objects at different: scales, rotations, lightings, from different sides, on different backgrounds - you should preferably have 2000 different images for each class or more, and you should train `2000*classes` iterations or more

- desirable that your training dataset include images with non-labeled objects that you do not want to detect - negative samples without bounded box (empty `.txt` files) - use as many images of negative samples as there are images with objects

- What is the best way to mark objects: label only the visible part of the object, or label the visible and overlapped part of the object, or label a little more than the entire object (with a little gap)? Mark as you like - how would you like it to be detected.

- for training with a large number of objects in each image, add the parameter `max=200` or higher value in the last `[yolo]`-layer or `[region]`-layer in your cfg-file (the global maximum number of objects that can be detected by YoloV3 is `0,0615234375*(width*height)` where are width and height are parameters from `[net]` section in cfg-file)

- for training for small objects (smaller than 16x16 after the image is resized to 416x416) - set `layers = 23` instead of https://github.com/AlexeyAB/darknet/blob/6f718c257815a984253346bba8fb7aa756c55090/cfg/yolov4.cfg#L895
- set `stride=4` instead of https://github.com/AlexeyAB/darknet/blob/6f718c257815a984253346bba8fb7aa756c55090/cfg/yolov4.cfg#L892
- set `stride=4` instead of https://github.com/AlexeyAB/darknet/blob/6f718c257815a984253346bba8fb7aa756c55090/cfg/yolov4.cfg#L989

- for training for both small and large objects use modified models:
- Full-model: 5 yolo layers: https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov3_5l.cfg
- Tiny-model: 3 yolo layers: https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov4-tiny-3l.cfg
- YOLOv4: 3 yolo layers: https://raw.githubusercontent.com/AlexeyAB/darknet/master/cfg/yolov4-custom.cfg

- If you train the model to distinguish Left and Right objects as separate classes (left/right hand, left/right-turn on road signs, ...) then for disabling flip data augmentation - add `flip=0` here: https://github.com/AlexeyAB/darknet/blob/3d2d0a7c98dbc8923d9ff705b81ff4f7940ea6ff/cfg/yolov3.cfg#L17

- General rule - your training dataset should include such a set of relative sizes of objects that you want to detect:
- `train_network_width * train_obj_width / train_image_width ~= detection_network_width * detection_obj_width / detection_image_width`
- `train_network_height * train_obj_height / train_image_height ~= detection_network_height * detection_obj_height / detection_image_height`

I.e. for each object from Test dataset there must be at least 1 object in the Training dataset with the same class_id and about the same relative size:

`object width in percent from Training dataset` ~= `object width in percent from Test dataset`

That is, if only objects that occupied 80-90% of the image were present in the training set, then the trained network will not be able to detect objects that occupy 1-10% of the image.

- to speedup training (with decreasing detection accuracy) set param `stopbackward=1` for layer-136 in cfg-file

- each: `model of object, side, illumination, scale, each 30 grad` of the turn and inclination angles - these are *different objects* from an internal perspective of the neural network. So the more *different objects* you want to detect, the more complex network model should be used.

- to make the detected bounded boxes more accurate, you can add 3 parameters `ignore_thresh = .9 iou_normalizer=0.5 iou_loss=giou` to each `[yolo]` layer and train, it will increase [email protected], but decrease [email protected].

- Only if you are an **expert** in neural detection networks - recalculate anchors for your dataset for `width` and `height` from cfg-file:
`darknet.exe detector calc_anchors data/obj.data -num_of_clusters 9 -width 416 -height 416`
then set the same 9 `anchors` in each of 3 `[yolo]`-layers in your cfg-file. But you should change indexes of anchors `masks=` for each [yolo]-layer, so for YOLOv4 the 1st-[yolo]-layer has anchors smaller than 30x30, 2nd smaller than 60x60, 3rd remaining, and vice versa for YOLOv3. Also you should change the `filters=(classes + 5)*` before each [yolo]-layer. If many of the calculated anchors do not fit under the appropriate layers - then just try using all the default anchors.

2. After training - for detection:

- Increase network-resolution by set in your `.cfg`-file (`height=608` and `width=608`) or (`height=832` and `width=832`) or (any value multiple of 32) - this increases the precision and makes it possible to detect small objects: [link](https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L8-L9)

- it is not necessary to train the network again, just use `.weights`-file already trained for 416x416 resolution

- to get even greater accuracy you should train with higher resolution 608x608 or 832x832, note: if error `Out of memory` occurs then in `.cfg`-file you should increase `subdivisions=16`, 32 or 64: [link](https://github.com/AlexeyAB/darknet/blob/0039fd26786ab5f71d5af725fc18b3f521e7acfd/cfg/yolov3.cfg#L4)

## How to mark bounded boxes of objects and create annotation files

Here you can find repository with GUI-software for marking bounded boxes of objects and generating annotation files for Yolo v2 - v4: https://github.com/AlexeyAB/Yolo_mark

With example of: `train.txt`, `obj.names`, `obj.data`, `yolo-obj.cfg`, `air`1-6`.txt`, `bird`1-4`.txt` for 2 classes of objects (air, bird) and `train_obj.cmd` with example how to train this image-set with Yolo v2 - v4

Different tools for marking objects in images:

1. in C++: https://github.com/AlexeyAB/Yolo_mark
2. in Python: https://github.com/tzutalin/labelImg
3. in Python: https://github.com/Cartucho/OpenLabeling
4. in C++: https://www.ccoderun.ca/darkmark/
5. in JavaScript: https://github.com/opencv/cvat
6. in C++: https://github.com/jveitchmichaelis/deeplabel
7. in C#: https://github.com/BMW-InnovationLab/BMW-Labeltool-Lite
8. DL-Annotator for Windows ($30): [url](https://www.microsoft.com/en-us/p/dlannotator/9nsx79m7t8fn?activetab=pivot:overviewtab)
9. v7labs - the greatest cloud labeling tool ($1.5 per hour): https://www.v7labs.com/

## How to use Yolo as DLL and SO libraries

- on Linux
- using `build.sh` or
- build `darknet` using `cmake` or
- set `LIBSO=1` in the `Makefile` and do `make`
- on Windows
- using `build.ps1` or
- build `darknet` using `cmake` or
- compile `build\darknet\yolo_cpp_dll.sln` solution or `build\darknet\yolo_cpp_dll_no_gpu.sln` solution

There are 2 APIs:

- C API: https://github.com/AlexeyAB/darknet/blob/master/include/darknet.h
- Python examples using the C API:
- https://github.com/AlexeyAB/darknet/blob/master/darknet.py
- https://github.com/AlexeyAB/darknet/blob/master/darknet_video.py

- C++ API: https://github.com/AlexeyAB/darknet/blob/master/include/yolo_v2_class.hpp
- C++ example that uses C++ API: https://github.com/AlexeyAB/darknet/blob/master/src/yolo_console_dll.cpp

----

1. To compile Yolo as C++ DLL-file `yolo_cpp_dll.dll` - open the solution `build\darknet\yolo_cpp_dll.sln`, set **x64** and **Release**, and do the: Build -> Build yolo_cpp_dll
- You should have installed **CUDA 10.2**
- To use cuDNN do: (right click on project) -> properties -> C/C++ -> Preprocessor -> Preprocessor Definitions, and add at the beginning of line: `CUDNN;`

2. To use Yolo as DLL-file in your C++ console application - open the solution `build\darknet\yolo_console_dll.sln`, set **x64** and **Release**, and do the: Build -> Build yolo_console_dll

- you can run your console application from Windows Explorer `build\darknet\x64\yolo_console_dll.exe`
**use this command**: `yolo_console_dll.exe data/coco.names yolov4.cfg yolov4.weights test.mp4`

- after launching your console application and entering the image file name - you will see info for each object:
` `
- to use simple OpenCV-GUI you should uncomment line `//#define OPENCV` in `yolo_console_dll.cpp`-file: [link](https://github.com/AlexeyAB/darknet/blob/a6cbaeecde40f91ddc3ea09aa26a03ab5bbf8ba8/src/yolo_console_dll.cpp#L5)
- you can see source code of simple example for detection on the video file: [link](https://github.com/AlexeyAB/darknet/blob/ab1c5f9e57b4175f29a6ef39e7e68987d3e98704/src/yolo_console_dll.cpp#L75)

`yolo_cpp_dll.dll`-API: [link](https://github.com/AlexeyAB/darknet/blob/master/src/yolo_v2_class.hpp#L42)

```cpp
struct bbox_t {
unsigned int x, y, w, h; // (x,y) - top-left corner, (w, h) - width & height of bounded box
float prob; // confidence - probability that the object was found correctly
unsigned int obj_id; // class of object - from range [0, classes-1]
unsigned int track_id; // tracking id for video (0 - untracked, 1 - inf - tracked object)
unsigned int frames_counter;// counter of frames on which the object was detected
};

class Detector {
public:
Detector(std::string cfg_filename, std::string weight_filename, int gpu_id = 0);
~Detector();

std::vector detect(std::string image_filename, float thresh = 0.2, bool use_mean = false);
std::vector detect(image_t img, float thresh = 0.2, bool use_mean = false);
static image_t load_image(std::string image_filename);
static void free_image(image_t m);

#ifdef OPENCV
std::vector detect(cv::Mat mat, float thresh = 0.2, bool use_mean = false);
std::shared_ptr mat_to_image_resize(cv::Mat mat) const;
#endif
};
```

## Citation

```
@misc{bochkovskiy2020yolov4,
title={YOLOv4: Optimal Speed and Accuracy of Object Detection},
author={Alexey Bochkovskiy and Chien-Yao Wang and Hong-Yuan Mark Liao},
year={2020},
eprint={2004.10934},
archivePrefix={arXiv},
primaryClass={cs.CV}
}
```

```
@InProceedings{Wang_2021_CVPR,
author = {Wang, Chien-Yao and Bochkovskiy, Alexey and Liao, Hong-Yuan Mark},
title = {{Scaled-YOLOv4}: Scaling Cross Stage Partial Network},
booktitle = {Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR)},
month = {June},
year = {2021},
pages = {13029-13038}
}
```