为了完成人工智能课的大作业，写了这个程序，代码比较简陋（

使用工具

本项目使用Anaconda搭建虚拟环境，所用python版本为3.10。机器学习框架选择PyTorch cuda 11.7版，训练显卡为NVIDIA RTX 2060，显存为6G。展示环节使用了第三方库gradio。

效果展示

详细内容及代码

项目地址：https://github.com/Astrophel02/ShipDetect

使用了https://opensar.sjtu.edu.cn 的opensarship-1 数据集，对数据集进行预处理使之大小适合网络。

处理后的数据集在这里：OneDrive

模型选用简单的AlexNet，最终识别准确率可以达到97%以上。

代码中，CNN_1是训练过程，CNN_2是展示过程，针对实验用数据集的预训练模型在这里：OneDrive，该模型可以直接在CNN_2.py中加载。全部代码如下：

CNN_1:

import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.optim as optim
from torchvision import datasets, transforms
import matplotlib.pyplot as plt
import numpy as np
#设置超参数
BATCH_SIZE=32
EPOCHS=20
DEVICE = torch.device("cuda") #选择计算硬件

transforms = transforms.Compose([
    #transforms.RandomCrop(32,padding=4),
    transforms.RandomHorizontalFlip(),
    transforms.ToTensor(),
    transforms.Normalize([0.5, 0.5, 0.5], [0.5, 0.5, 0.5])
])

train_path = "D:\\ship\\train"   #修改数据集位置
train_dataset = datasets.ImageFolder(train_path, transform=transforms)
test_path = "D:\\ship\\test"     #修改数据集位置
test_dataset = datasets.ImageFolder(test_path, transform=transforms)

train_loader = torch.utils.data.DataLoader(
    train_dataset, batch_size=BATCH_SIZE, shuffle=True, num_workers=6)
test_loader = torch.utils.data.DataLoader(
    test_dataset, batch_size=BATCH_SIZE, shuffle=False, num_workers=6)
#定义网络
class AlexNet(nn.Module):
    def __init__(self):
        super(AlexNet, self).__init__()
        self.conv = nn.Sequential(
            nn.Conv2d(3, 96, 11, 4), # in_channels, out_channels, kernel_size, stride, padding
            nn.ReLU(),
            nn.MaxPool2d(3, 2), # kernel_size, stride
            # 减小卷积窗口，使用填充为2来使得输入与输出的高和宽一致，且增大输出通道数
            nn.Conv2d(96, 256, 5, 1, 2),
            nn.ReLU(),
            nn.MaxPool2d(3, 2),
            # 连续3个卷积层，且使用更小的卷积窗口。除了最后的卷积层外，进一步增大了输出通道数。
            nn.Conv2d(256, 384, 3, 1, 1),
            nn.ReLU(),
            nn.Conv2d(384, 384, 3, 1, 1),
            nn.ReLU(),
            nn.Conv2d(384, 256, 3, 1, 1),
            nn.ReLU(),
            nn.MaxPool2d(3, 2)
        )
        self.fc = nn.Sequential(
            nn.Linear(256*5*5, 4096),
            nn.ReLU(),
            nn.Dropout(0.5),
            nn.Linear(4096, 4096),
            nn.ReLU(),
            nn.Dropout(0.5),
            nn.Linear(4096, 2),
        )

    def forward(self, img):
        feature = self.conv(img)
        output = self.fc(feature.view(img.shape[0], -1))
        return output

model=AlexNet().to(DEVICE)
weights = [1.0,3]
class_weights = torch.FloatTensor(weights).to(DEVICE)
criterion = nn.CrossEntropyLoss(weight=class_weights)
optimizer = torch.optim.Adam(model.parameters(), lr=0.00005)

def train(model, device, train_loader, optimizer, epoch):
    model.train()
    for batch_idx, (data, target) in enumerate(train_loader):
        data, target = data.to(device), target.to(device)
        optimizer.zero_grad()
        output=model(data)
        loss=criterion(output,target)
        loss.backward()
        optimizer.step()
        if (batch_idx + 1) % 30 == 0:
            print('Train Epoch: {} [{}/{} ({:.0f}%)]\tLoss: {:.6f}'.format(
                epoch, batch_idx * len(data), len(train_loader.dataset),
                       100. * batch_idx / len(train_loader), loss.item()))

def test(model,device,test_loader):
    model.eval()
    test_loss=0
    correct=0
    with torch.no_grad():
        for data,target in test_loader:
            data,target=data.to(device),target.to(device)
            output=model(data)
            test_loss += F.nll_loss(output, target, reduction='sum').item()
            pred = output.max(1, keepdim=True)[1]
            correct += pred.eq(target.view_as(pred)).sum().item()
    test_loss /= len(test_loader.dataset)
    print('\nTest set: Average loss: {:.4f}, Accuracy: {}/{} ({:.0f}%)\n'.format(
        test_loss, correct, len(test_loader.dataset),
        100. * correct / len(test_loader.dataset)))


for epoch in range(EPOCHS):
    #test(model, DEVICE, test_loader,loss)
    train(model,DEVICE,train_loader,optimizer,epoch)
    test(model,DEVICE,test_loader)
#保存模型
MODEL_PATH = "./Model.pth"
torch.save(model,MODEL_PATH)

CNN_2:

import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.optim as optim
from torchvision import datasets, transforms
import gradio

class AlexNet(nn.Module):
    def __init__(self):
        super(AlexNet, self).__init__()
        self.conv = nn.Sequential(
            nn.Conv2d(3, 96, 11, 4), # in_channels, out_channels, kernel_size, stride, padding
            nn.ReLU(),
            nn.MaxPool2d(3, 2), # kernel_size, stride
            # 减小卷积窗口，使用填充为2来使得输入与输出的高和宽一致，且增大输出通道数
            nn.Conv2d(96, 256, 5, 1, 2),
            nn.ReLU(),
            nn.MaxPool2d(3, 2),
            # 连续3个卷积层，且使用更小的卷积窗口。除了最后的卷积层外，进一步增大了输出通道数。
            nn.Conv2d(256, 384, 3, 1, 1),
            nn.ReLU(),
            nn.Conv2d(384, 384, 3, 1, 1),
            nn.ReLU(),
            nn.Conv2d(384, 256, 3, 1, 1),
            nn.ReLU(),
            nn.MaxPool2d(3, 2)
        )
        self.fc = nn.Sequential(
            nn.Linear(256*5*5, 4096),
            nn.ReLU(),
            nn.Dropout(0.5),
            nn.Linear(4096, 4096),
            nn.ReLU(),
            nn.Dropout(0.5),
            nn.Linear(4096, 2),
        )

    def forward(self, img):
        feature = self.conv(img)
        output = self.fc(feature.view(img.shape[0], -1))
        return output
#加载模型
device=torch.device("cuda")
model = torch.load("./Model.pth")
model.to(device)
#model.eval()

device=torch.device('cuda')
transform = transforms.Compose([
    transforms.RandomHorizontalFlip(),
    transforms.ToTensor(),
    transforms.Normalize([0.5, 0.5, 0.5], [0.5, 0.5, 0.5])
])
test_path = "D:\\ship\\test"
test_dataset = datasets.ImageFolder(test_path, transform=transform)
test_loader = torch.utils.data.DataLoader(
    test_dataset, batch_size=32, shuffle=False, num_workers=6)
def test(model,device,test_loader):
    model.eval()
    test_loss=0
    correct=0
    with torch.no_grad():
        for data,target in test_loader:
            data,target=data.to(device),target.to(device)
            output=model(data)
            test_loss += F.nll_loss(output, target, reduction='sum').item()
            pred = output.max(1, keepdim=True)[1]
            correct += pred.eq(target.view_as(pred)).sum().item()
    test_loss /= len(test_loader.dataset)
    print('\nTest set: Average loss: {:.4f}, Accuracy: {}/{} ({:.0f}%)\n'.format(
        test_loss, correct, len(test_loader.dataset),
        100. * correct / len(test_loader.dataset)))
test(model, device, test_loader)
#可视化
labels=["未检测到船只","检测到船只"]
def predict(inp):
    #model.eval()
    img = transforms.ToTensor()(inp)
    img = transforms.Normalize([0.5, 0.5, 0.5], [0.5, 0.5, 0.5])(img)
    img = img.unsqueeze(0)
    img = img.to(device)
    with torch.no_grad():
        prediction = torch.nn.functional.softmax(model(img)[0], dim=0)
        confidences = {labels[i]: float(prediction[i]) for i in range(2)}
    return confidences
def test(inp):
    img = transforms.ToTensor()(inp)
    img = img.unsqueeze(0)
    return img.shape

inp = gradio.Image()
io = gradio.Interface(fn=predict,inputs=inp,outputs="label",live=True)
io.launch()

遇到的坑

1）模型选择不恰当。开始选择了VGG-16作为模型，结果无法拟合；

2）结果展示过程忘记对输入图片进行预处理，导致结果不准确；

3）数据集正反样本数量不均匀，导致模型更倾向于预测无船只，解决方法是为损失函数增加权重。