【yolov8目标检测】使用yolov8训练自己的数据集

准备数据集

python安装yolov8

配置yaml

从0开始训练

从预训练模型开始训练

准备数据集

首先得准备好数据集，你的数据集至少包含images和labels，严格来说你的images应该包含训练集train、验证集val和测试集test，不过为了简单说明使用步骤，其中test可以不要，val和train可以用同一个，因此我这里只用了一个images

其中images装的是图片数据，labels装的是与图片一一对应同名的yolo格式txt，即类别号，经过归一化的中心x和y坐标以及宽和高

python安装yolov8

然后我们开始准备yolov8，使用python的API的话就比较简单，首先安装一下yolov8

用pip的话安装的话

pip install ultralytics

使用pycharm安装的话

配置yaml

安装完了之后，差不多就可以开始了，我们首先看看官方给的代码

from ultralytics import YOLO

# Load a model
model = YOLO("yolov8n.yaml")  # build a new model from scratch
model = YOLO("yolov8n.pt")  # load a pretrained model (recommended for training)

# Use the model
model.train(data="coco128.yaml", epochs=3)  # train the model
metrics = model.val()  # evaluate model performance on the validation set
results = model("https://ultralytics.com/images/bus.jpg")  # predict on an image
path = model.export(format="onnx")  # export the model to ONNX format

其中迷惑的是yolov8n.yaml、yolov8n.pt和coco128.yaml这几个文件，yolov8n.yaml是yolov8的配置，yolov8n.pt是预训练的模型，coco128.yaml是coco数据集的配置参数

因此如果我们想要训练自己的模型的话，需要修改一下配置文件，首先到GitHub上下载yolov8n.yaml和coco128.yaml下来，这两个文件的位置有可能会变，所以最好在仓库上直接搜索

大概长这样，你也可以自己创建，然后把内容复制进去

yolov8n.yaml

# Ultralytics YOLO 🚀, AGPL-3.0 license
# YOLOv8 object detection model with P3-P5 outputs. For Usage examples see https://docs.ultralytics.com/tasks/detect

# Parameters
nc: 80  # number of classes
scales: # model compound scaling constants, i.e. 'model=yolov8n.yaml' will call yolov8.yaml with scale 'n'
  # [depth, width, max_channels]
  n: [0.33, 0.25, 1024]  # YOLOv8n summary: 225 layers,  3157200 parameters,  3157184 gradients,   8.9 GFLOPs
  s: [0.33, 0.50, 1024]  # YOLOv8s summary: 225 layers, 11166560 parameters, 11166544 gradients,  28.8 GFLOPs
  m: [0.67, 0.75, 768]   # YOLOv8m summary: 295 layers, 25902640 parameters, 25902624 gradients,  79.3 GFLOPs
  l: [1.00, 1.00, 512]   # YOLOv8l summary: 365 layers, 43691520 parameters, 43691504 gradients, 165.7 GFLOPs
  x: [1.00, 1.25, 512]   # YOLOv8x summary: 365 layers, 68229648 parameters, 68229632 gradients, 258.5 GFLOPs

# YOLOv8.0n backbone
backbone:
  # [from, repeats, module, args]
  - [-1, 1, Conv, [64, 3, 2]]  # 0-P1/2
  - [-1, 1, Conv, [128, 3, 2]]  # 1-P2/4
  - [-1, 3, C2f, [128, True]]
  - [-1, 1, Conv, [256, 3, 2]]  # 3-P3/8
  - [-1, 6, C2f, [256, True]]
  - [-1, 1, Conv, [512, 3, 2]]  # 5-P4/16
  - [-1, 6, C2f, [512, True]]
  - [-1, 1, Conv, [1024, 3, 2]]  # 7-P5/32
  - [-1, 3, C2f, [1024, True]]
  - [-1, 1, SPPF, [1024, 5]]  # 9

# YOLOv8.0n head
head:
  - [-1, 1, nn.Upsample, [None, 2, 'nearest']]
  - [[-1, 6], 1, Concat, [1]]  # cat backbone P4
  - [-1, 3, C2f, [512]]  # 12

  - [-1, 1, nn.Upsample, [None, 2, 'nearest']]
  - [[-1, 4], 1, Concat, [1]]  # cat backbone P3
  - [-1, 3, C2f, [256]]  # 15 (P3/8-small)

  - [-1, 1, Conv, [256, 3, 2]]
  - [[-1, 12], 1, Concat, [1]]  # cat head P4
  - [-1, 3, C2f, [512]]  # 18 (P4/16-medium)

  - [-1, 1, Conv, [512, 3, 2]]
  - [[-1, 9], 1, Concat, [1]]  # cat head P5
  - [-1, 3, C2f, [1024]]  # 21 (P5/32-large)

  - [[15, 18, 21], 1, Detect, [nc]]  # Detect(P3, P4, P5)

coco128.yaml

# Ultralytics YOLO 🚀, AGPL-3.0 license
# COCO128 dataset https://www.kaggle.com/ultralytics/coco128 (first 128 images from COCO train2017) by Ultralytics
# Example usage: yolo train data=coco128.yaml
# parent
# ├── ultralytics
# └── datasets
#     └── coco128  ← downloads here (7 MB)


# Train/val/test sets as 1) dir: path/to/imgs, 2) file: path/to/imgs.txt, or 3) list: [path/to/imgs1, path/to/imgs2, ..]
path: ../datasets/coco128  # dataset root dir
train: images/train2017  # train images (relative to 'path') 128 images
val: images/train2017  # val images (relative to 'path') 128 images
test:  # test images (optional)

# Classes
names:
  0: person
  1: bicycle
  2: car
  3: motorcycle
  4: airplane
  5: bus
  6: train
  7: truck
  8: boat
  9: traffic light
  10: fire hydrant
  11: stop sign
  12: parking meter
  13: bench
  14: bird
  15: cat
  16: dog
  17: horse
  18: sheep
  19: cow
  20: elephant
  21: bear
  22: zebra
  23: giraffe
  24: backpack
  25: umbrella
  26: handbag
  27: tie
  28: suitcase
  29: frisbee
  30: skis
  31: snowboard
  32: sports ball
  33: kite
  34: baseball bat
  35: baseball glove
  36: skateboard
  37: surfboard
  38: tennis racket
  39: bottle
  40: wine glass
  41: cup
  42: fork
  43: knife
  44: spoon
  45: bowl
  46: banana
  47: apple
  48: sandwich
  49: orange
  50: broccoli
  51: carrot
  52: hot dog
  53: pizza
  54: donut
  55: cake
  56: chair
  57: couch
  58: potted plant
  59: bed
  60: dining table
  61: toilet
  62: tv
  63: laptop
  64: mouse
  65: remote
  66: keyboard
  67: cell phone
  68: microwave
  69: oven
  70: toaster
  71: sink
  72: refrigerator
  73: book
  74: clock
  75: vase
  76: scissors
  77: teddy bear
  78: hair drier
  79: toothbrush


# Download script/URL (optional)
download: https://ultralytics.com/assets/coco128.zip

然后修改yolov8n.yaml，把nc的数值改成你的数据集的类别数，我这里的数据集只有乌骨鸡和狮头鹅两个

# Ultralytics YOLO 🚀, AGPL-3.0 license
# YOLOv8 object detection model with P3-P5 outputs. For Usage examples see https://docs.ultralytics.com/tasks/detect

# Parameters
nc: 2  # number of classes
scales: # model compound scaling constants, i.e. 'model=yolov8n.yaml' will call yolov8.yaml with scale 'n'
  # [depth, width, max_channels]
  n: [0.33, 0.25, 1024]  # YOLOv8n summary: 225 layers,  3157200 parameters,  3157184 gradients,   8.9 GFLOPs
  s: [0.33, 0.50, 1024]  # YOLOv8s summary: 225 layers, 11166560 parameters, 11166544 gradients,  28.8 GFLOPs
  m: [0.67, 0.75, 768]   # YOLOv8m summary: 295 layers, 25902640 parameters, 25902624 gradients,  79.3 GFLOPs
  l: [1.00, 1.00, 512]   # YOLOv8l summary: 365 layers, 43691520 parameters, 43691504 gradients, 165.7 GFLOPs
  x: [1.00, 1.25, 512]   # YOLOv8x summary: 365 layers, 68229648 parameters, 68229632 gradients, 258.5 GFLOPs

# YOLOv8.0n backbone
backbone:
  # [from, repeats, module, args]
  - [-1, 1, Conv, [64, 3, 2]]  # 0-P1/2
  - [-1, 1, Conv, [128, 3, 2]]  # 1-P2/4
  - [-1, 3, C2f, [128, True]]
  - [-1, 1, Conv, [256, 3, 2]]  # 3-P3/8
  - [-1, 6, C2f, [256, True]]
  - [-1, 1, Conv, [512, 3, 2]]  # 5-P4/16
  - [-1, 6, C2f, [512, True]]
  - [-1, 1, Conv, [1024, 3, 2]]  # 7-P5/32
  - [-1, 3, C2f, [1024, True]]
  - [-1, 1, SPPF, [1024, 5]]  # 9

# YOLOv8.0n head
head:
  - [-1, 1, nn.Upsample, [None, 2, 'nearest']]
  - [[-1, 6], 1, Concat, [1]]  # cat backbone P4
  - [-1, 3, C2f, [512]]  # 12

  - [-1, 1, nn.Upsample, [None, 2, 'nearest']]
  - [[-1, 4], 1, Concat, [1]]  # cat backbone P3
  - [-1, 3, C2f, [256]]  # 15 (P3/8-small)

  - [-1, 1, Conv, [256, 3, 2]]
  - [[-1, 12], 1, Concat, [1]]  # cat head P4
  - [-1, 3, C2f, [512]]  # 18 (P4/16-medium)

  - [-1, 1, Conv, [512, 3, 2]]
  - [[-1, 9], 1, Concat, [1]]  # cat head P5
  - [-1, 3, C2f, [1024]]  # 21 (P5/32-large)

  - [[15, 18, 21], 1, Detect, [nc]]  # Detect(P3, P4, P5)

然后修改coco128.yaml，我把文件名也改成了data.yaml，path改成images和labels的上一级目录地址，train改成训练集相对于path的地址，val也是改成验证集的相对于path的地址，我这里训练集和验证集用的是同一个嘿嘿嘿，然后把test注释掉，因为我没用测试集，还有就是names那里改成你的训练集的类别名，并把多余的类别删掉

# Ultralytics YOLO 🚀, AGPL-3.0 license
# COCO128 dataset https://www.kaggle.com/ultralytics/coco128 (first 128 images from COCO train2017) by Ultralytics
# Example usage: yolo train data=coco128.yaml
# parent
# ├── ultralytics
# └── datasets
#     └── coco128  ← downloads here (7 MB)


# Train/val/test sets as 1) dir: path/to/imgs, 2) file: path/to/imgs.txt, or 3) list: [path/to/imgs1, path/to/imgs2, ..]
path: C:/Users/Yezi/Desktop/人工智能实训/HW2/data # dataset root dir
train: images # train images (relative to 'path') 128 images
val: images # val images (relative to 'path') 128 images
#test:  # test images (optional)

# Classes
names:
  0: goose
  1: chicken

这样子就配置好了

然后开始训练

从0开始训练

下面是从0开始训练的过程

其实训练的代码就两行

model = YOLO("yolov8n.yaml")  # build a new model from scratch
model.train(data="data.yaml", epochs=5)  # train the model

不过从0开始训练的效果并不好，下面是我自己的测试代码，由于我电脑比较烂，GPU摆不上用场，所以只能用cpu训练

from ultralytics import YOLO
import matplotlib.pyplot as plt

model = YOLO("yolov8n.yaml")  # build a new model from scratch
model.train(data="data.yaml", epochs=30, device='cpu')  # train the model
model.val(data="data.yaml")
results = model(r"C:\Users\Yezi\Desktop\人工智能实训\HW2\data\images\00909.jpg")  # predict on an image
plt.imshow(results[0].plot())
plt.show()
results = model(r"C:\Users\Yezi\Desktop\人工智能实训\HW2\data\images\100318.jpg")  # predict on an image
plt.imshow(results[0].plot())
plt.show()

从预训练模型开始训练

官方推荐用预训练好的模型开始训练

首先下载一个官方预训练好的模型

我这里下载的是yolov8n

然后使用预训练模型训练我的数据集

from ultralytics import YOLO
import matplotlib.pyplot as plt

model=YOLO("yolov8n.pt")
model.train(data="data.yaml", epochs=30, device='cpu')  # train the model
model.val(data="data.yaml")
results = model(r"C:\Users\Yezi\Desktop\人工智能实训\HW2\data\images\00909.jpg")  # predict on an image
plt.imshow(results[0].plot())
plt.show()
results = model(r"C:\Users\Yezi\Desktop\人工智能实训\HW2\data\images\100318.jpg")  # predict on an image
plt.imshow(results[0].plot())
plt.show()

乌骨鸡的效果是这样的