def __call__(self): # 图像转换 data_transorform = torchvision.transforms.Compose([ torchvision.transforms.Resize((224, 224)), torchvision.transforms.CenterCrop((224, 224)), torchvision.transforms.ToTensor(), torchvision.transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) img_list = glob.glob(self.img_dir + os.sep + "*.png") for imgpath in img_list: img = cv2.imread(imgpath) new_img = self.expend_img(img) # 补边 img = Image.fromarray(new_img) img = data_transorform(img) # 转换 img = torch.reshape(img, (-1, 3, self.imgsz, self.imgsz)).to(device) # 维度转换[B,C,H,W] pred = self.model(img) _, pred = torch.max(pred, 1) outputs = self.class_name[pred] print("Image path:", imgpath, " pred:", outputs) # 补边为正方形 def expend_img(self, img, fill_pix=122): ''' :param img: 图片数据 :param fill_pix: 填充像素，默认为灰色，自行更改 :return: ''' h, w = img.shape[:2] # 获取图像的宽高 if h >= w: # 左右填充 padd_width = int(h - w) // 2 padd_h, padd_b, padd_l, padd_r = 0, 0, padd_width, padd_width # 获取上下左右四个方向需要填充的像素 elif h < w: # 上下填充 padd_high = int(w - h) // 2 padd_h, padd_b, padd_l, padd_r = padd_high, padd_high, 0, 0 new_img = cv2.copyMakeBorder(img, padd_h, padd_b, padd_l, padd_r, borderType=cv2.BORDER_CONSTANT, value=[fill_pix, fill_pix, fill_pix]) return new_img if __name__ == '__main__': opt = parser_opt() test_img = Test_model(opt) test_img()

PyTorch torchvision.models 源码解读与使用

torchvision.models模块是PyTorch框架中一个非常重要且好用的包，主要由三个子包组成，分别是torchvision.datasets、torchvision.models、torchvision.transforms。其中，torchvision.models模块提供了常用的网络...

YOLOv4中dataloader的get_random_data模块参数详解

这些操作是通过调用PyTorch的图像变换函数库（如torchvision.transforms）或自定义的图像处理函数来实现的。在具体编码实现时，可以通过设置相应的参数来控制是否启用上述提到的各种数据增强策略。总之，YOLOV4的...

class CocoDetection(torchvision.datasets.CocoDetection): def init(self, img_folder, ann_file, transforms, return_masks): super(CocoDetection, self).init(img_folder, ann_file) self._transforms = transforms self.prepare = ConvertCocoPolysToMask(return_masks) def getitem(self, idx): img, target = super(CocoDetection, self).getitem(idx) image_id = self.ids[idx] target = {'image_id': image_id, 'annotations': target} img, target = self.prepare(img, target) if self._transforms is not None: img, target = self._transforms(img, target) return img, target怎么进行更改

在 __getitem__ 方法中，它首先调用父类的 __getitem__ 方法获取图像和目标信息，然后将目标信息转换为 COCO 标注格式，并且应用了一些预处理操作（例如将多边形转换为掩膜）。如果你要为该类添加多尺度训练的...

import torch import torchvision import torch.nn as nn import torchvision.transforms as transforms #超参数 num_classes = 10 #类别个数 num_epochs = 10 #迭代次数/训练次数 learning_rate = 0.01 #学习率，方法更新的速率 batch_size = 64 #批次，批量大小，每次传输图片的个数 #训练集 train_dataset = torchvision.datasets.MNIST(root = './data', train = True, download = True, transform = transforms.Compose([ transforms.Resize((28,28)),transforms.ToTensor()]) ) #测试集 test_dataset = torchvision.datasets.MNIST(root = './data', train = False, download = True, transform = transforms.Compose([ transforms.Resize((28,28)),transforms.ToTensor()]) )

这里使用了两个预处理操作：Resize将图像大小调整为28x28像素，ToTensor将图像转换为Tensor类型。这样，训练集和测试集的数据集对象就创建好了。接下来可以使用DataLoader来实现数据的批量加载和随机打乱。

请解释这行代码transform = torchvision.transforms.Compose([ torchvision.transforms.Resize((224, 224)), torchvision.transforms.ToTensor(), ])

2. torchvision.transforms.ToTensor()：将 PIL 图像转换为 PyTorch 张量。这个 Compose 对象将执行两个操作，首先将输入图像调整为 (224, 224) 的大小，然后将其转换为张量。这是一个常见的数据预处理步骤，用于...

修改import torch import torchvision.models as models vgg16_model = models.vgg16(pretrained=True) import torch.nn as nn import torch.nn.functional as F import torchvision.transforms as transforms from PIL import Image # 加载图片 img_path = "pic.jpg" img = Image.open(img_path) # 定义预处理函数 preprocess = transforms.Compose([ transforms.Resize(256), transforms.CenterCrop(224), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) # 预处理图片，并添加一个维度(batch_size) img_tensor = preprocess(img).unsqueeze(0) # 提取特征 features = vgg16_model.features(img_tensor) import numpy as np import matplotlib.pyplot as plt def deconv_visualization(model, features, layer_idx, iterations=30, lr=1, figsize=(10, 10)): # 获取指定层的输出特征 output = features[layer_idx] # 定义随机输入张量，并启用梯度计算 #input_tensor = torch.randn(output.shape, requires_grad=True) input_tensor = torch.randn(1, 3, output.shape[2], output.shape[3], requires_grad=True) # 定义优化器 optimizer = torch.optim.Adam([input_tensor], lr=lr) for i in range(iterations): # 将随机张量输入到网络中，得到对应的输出 model.zero_grad() #x = model.features(input_tensor) x = model.features:layer_idx # 计算输出与目标特征之间的距离，并进行反向传播 loss = F.mse_loss(x[layer_idx], output) loss.backward() # 更新输入张量 optimizer.step() # 反归一化 input_tensor = (input_tensor - input_tensor.min()) / (input_tensor.max() - input_tensor.min()) # 将张量转化为numpy数组 img = input_tensor.squeeze(0).detach().numpy().transpose((1, 2, 0)) # 绘制图像 plt.figure(figsize=figsize) plt.imshow(img) plt.axis("off") plt.show() # 可视化第一层特征 deconv_visualization(vgg16_model, features, 0)使其不产生报错IndexError: tuple index out of range

preprocess = transforms.Compose([ transforms.Resize(256), transforms.CenterCrop(224), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) # ...

通过这个代码：import torch import torchvision.transforms as transforms from PIL import Image # 定义AutoAugment增强策略 policy = transforms.AutoAugmentPolicy.IMAGENET # 定义transforms transform = transforms.Compose([ transforms.Resize(256), transforms.CenterCrop(224), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]), transforms.AutoAugment(policy) ]) # 加载图像 img = Image.open('path/to/image.jpg') # 进行数据增强 img_augmented = transform(img)可以得到原始数据多少倍的数据呢

在上面的代码中，使用了AutoAugment增强策略来进行数据增强，它可以生成大量不同的图像变换。因此，可以得到原始数据的多个变形，具体的变形倍数取决于使用的增强策略和参数设置。但是，增强的倍数不是一个确定的值...

transform_train = torchvision.transforms.Compose([ # 对每张图片进行170*170的中心裁剪 torchvision.transforms.CenterCrop((170, 170)), # 对每张图片进行随机翻转 torchvision.transforms.RandomHorizontalFlip(), # 把图片变成tensor张量 torchvision.transforms.ToTensor(), # 标准化图像的每个通道 torchvision.transforms.Normalize([0.4914, 0.4822, 0.4465], [0.2023, 0.1994, 0.2010])]) # 在检测期间，对图像执行标准化，以消除评估结果中的随机性 transform_test = torchvision.transforms.Compose([ torchvision.transforms.ToTensor(), torchvision.transforms.Normalize([0.4914, 0.4822, 0.4465], [0.2023, 0.1994, 0.2010])]) RuntimeError: stack expects each tensor to be equal size, but got [3, 198, 170] at entry 0 and [3, 301, 190] at entry 1 根据报错优化代码

transform_train = torchvision.transforms.Compose([ # 对每张图片进行170*170的中心裁剪 torchvision.transforms.CenterCrop((170, 170)), # 对每张图片进行随机翻转 torchvision.transforms....

import torch import torch.nn as nn import torch.optim as optim import numpy as np from torch.autograd import Variable from torchvision.datasets import ImageFolder from torchvision.transforms import transforms from torch.utils.data import DataLoader # 定义超参数 num_epochs = 10 batch_size = 32 learning_rate = 0.001 # 定义数据转换方式 transform = transforms.Compose([ transforms.Resize((32, 32)), transforms.ToTensor(), transforms.Normalize(mean=[0.5], std=[0.5]) ]) # 加载数据集 train_dataset = ImageFolder(root='./ChineseStyle/train/', transform=transform) train_loader = DataLoader(train_dataset, batch_size=batch_size, shuffle=True) test_dataset = ImageFolder(root='./ChineseStyle/test/', transform=transform) test_loader = DataLoader(test_dataset, batch_size=batch_size, shuffle=True) # 定义卷积神经网络结构 class Net(nn.Module): def init(self): super(Net, self).init() self.conv1 = nn.Conv2d(in_channels=3, out_channels=6, kernel_size=5, stride=1, padding=2) self.pool = nn.MaxPool2d(kernel_size=2, stride=2) self.conv2 = nn.Conv2d(in_channels=6, out_channels=32, kernel_size=5, stride=1, padding=2) self.fc1 = nn.Linear(in_features=32 * 8 * 8, out_features=128) self.fc2 = nn.Linear(in_features=128, out_features=15) def forward(self, x): x = self.pool(torch.relu(self.conv1(x))) x = self.pool(torch.relu(self.conv2(x))) x = x.view(-1, 32 * 8 * 8) x = torch.relu(self.fc1(x)) x = self.fc2(x) return x # 实例化卷积神经网络 net = Net() # 定义损失函数和优化器 criterion = nn.CrossEntropyLoss() optimizer = optim.Adam(net.parameters(), lr=learning_rate) # 训练模型 for epoch in range(num_epochs): for i, (images, labels) in enumerate(train_loader): # 将输入和标签转换为变量 images = Variable(images) labels = Variable(labels) # 将梯度清零 optimizer.zero_grad() # 向前传递 outputs = net(images) # 计算损失函数 loss = criterion(outputs, labels) # 反向传播和优化 loss.backward() optimizer.step() # 打印统计信息 if (i + 1) % 100 == 0: print('Epoch [%d/%d], Step [%d/%d], Loss: %.4f' % (epoch + 1, num_epochs, i + 1, len(train_dataset) // batch_size, loss.item())) # 测试模型 correct = 0 total = 0 for images, labels in test_loader: # 向前传递 outputs = net(Variable(images)) # 获取预测结果 _, predicted = torch.max(outputs.data, 1) # 更新统计信息 total += labels.size(0) correct += (predicted == labels).sum() # 计算准确率 print('Accuracy of the network on the test images: %d %%' % (100 * correct / total))有没有测试到测试集

_, predicted = torch.max(outputs.data, 1) # 更新统计信息 total += labels.size(0) correct += (predicted == labels).sum() # 计算准确率 print('Accuracy of the network on the test images: %d %%' % ...

def train(**kwargs): for k_, v_ in kwargs.items(): setattr(opt, k_, v_) device = t.device('cuda') if opt.gpu else t.device('cpu') if opt.vis: from visualize import Visualizer vis = Visualizer(opt.env) # 数据 transforms = tv.transforms.Compose([ tv.transforms.Resize(opt.image_size), tv.transforms.CenterCrop(opt.image_size), tv.transforms.ToTensor(), tv.transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5)) ]) dataset = tv.datasets.ImageFolder(opt.data_path, transform=transforms) dataloader = t.utils.data.DataLoader(dataset, batch_size=opt.batch_size, shuffle=True, num_workers=opt.num_workers, drop_last=True )的含义

5. 加载数据集，使用ImageFolder类读取opt.data_path路径下的图片，并使用上一步定义的transforms进行预处理。将处理后的数据集分成大小为opt.batch_size的多个批次，并使用DataLoader类将它们打包成一个可迭代的...

transforms = transforms.Compose([ # transforms.Resize(256), # 将图片短边缩放至256，长宽比保持不变： # transforms.CenterCrop(224), # 将图片从中心切剪成3224224大小的图片 transforms.ToTensor() # 把图片进行归一化，并把数据转换成Tensor类型 ])优化代码

在上面的代码中，使用 torchvision.transforms 模块中的 Compose 类将多个图像变换组合起来。其中，Resize 类将图像缩放到指定大小，CenterCrop 类将图像从中心裁剪出指定大小的图片，ToTensor 类将图像...

import torch import torch.nn as nn import torch.nn.functional as F import torchvision.transforms as transforms from PIL import Image # 定义一个简单的卷积神经网络（CNN）用于特征提取 class Net(nn.Module): def init(self): super(Net, self).init() self.conv1 = nn.Conv2d(3, 6, 5) self.pool = nn.MaxPool2d(2, 2) self.conv2 = nn.Conv2d(6, 16, 5) self.fc1 = nn.Linear(16 * 5 * 5, 120) self.fc2 = nn.Linear(120, 84) self.fc3 = nn.Linear(84, 10) def forward(self, x): x = self.pool(F.relu(self.conv1(x))) x = self.pool(F.relu(self.conv2(x))) x = x.view(-1, 16 * 5 * 5) x = F.relu(self.fc1(x)) x = F.relu(self.fc2(x)) x = self.fc3(x) return x # 加载图像 img = Image.open('test.jpg') # 对图像进行预处理，将其转换为模型所需的输入格式 transform = transforms.Compose([ transforms.Resize(256), transforms.CenterCrop(224), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) img_tensor = transform(img).unsqueeze(0) # 初始化模型并对图像进行特征提取 model = Net() features = model(img_tensor) # 将特征图还原回原始图像大小 upsample = nn.Upsample(scale_factor=2, mode='nearest') upsampled_features = upsample(features) # 显示原始图像和还原后的特征图 img.show() tensor_to_image = transforms.ToPILImage() upsampled_image = tensor_to_image(upsampled_features.squeeze(0).detach().cpu()) upsampled_image.show()，上述代码出现问题：RuntimeError: shape '[-1, 400]' is invalid for input of size 44944

这个错误提示表明你的代码在某个地方使用了错误的形状(-1,400)，而实际上输入的大小为44944，不能匹配。具体来说，这可能是由于在模型的某个层中使用了错误的形状导致的。为了解决这个错误，你需要检查代码中所有与...

--------------------------------------------------------------------------- TypeError Traceback (most recent call last) Cell In[31], line 8 6 print('sample:',x.shape,y.shape) 7 if name == 'main': ----> 8 main() Cell In[31], line 5, in main() 2 viz= visdom.Visdom() 4 db = Pokemon('pokemon',224,'train') #因为在当前文件夹下只需要文件名 ----> 5 x,y = next(iter(db)) 6 print('sample:',x.shape,y.shape) Cell In[30], line 87, in Pokemon.getitem(self, idx) 76 img, label = self.images[idx], self.labels[idx] 77 tf = transforms.Compose([ 78 lambda x:Image.open(img).convert('RGB'), #string path=>image data 79 transforms.Resize((self.resize,self.resize)), (...) 85 """ 86 ]) ---> 87 img = tf(img) 88 label = torch.tensor(label) 89 return img,label File D:\Anaconda\envs\gpu_pytorch\lib\site-packages\torchvision\transforms\transforms.py:95, in Compose.call(self, img) 93 def call(self, img): 94 for t in self.transforms: ---> 95 img = t(img) 96 return img TypeError: 'str' object is not callable

你可以使用transforms.ToPILImage()函数将路径转换为图像数据对象，然后再将其传递给transforms.Compose。以下是修改后的代码示例： python from PIL import Image import torchvision.transforms as ...

def extract_features(img): # Load the pre-trained MobileNetV3-Large model model = models.mobilenet_v3_large(weights = models.MobileNet_V3_Large_Weights.IMAGENET1K_V1) model.classifier[-1] = torch.nn.Identity() # Set the model to evaluation mode model.eval() # Define the image transformation pipeline transform = transforms.Compose([ transforms.Resize(256), transforms.CenterCrop(224), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) # Apply the image transformation pipeline img = transform(img) # Add an extra batch dimension to the image img = img.unsqueeze(0) # Pass the image through the model to obtain the features with torch.no_grad(): features = model.features(img) features = model.avgpool(features) features = torch.flatten(features, 1) features = model.classifier(features) # Convert the features to a numpy array features = features.squeeze() # Return the features as a numpy array return features

3. 定义一个图像变换的管道，包括缩放、中心裁剪、转换为张量和归一化等步骤，用于对输入的图像进行必要的预处理。 4. 对输入的图像进行预处理，并添加一个额外的批次维度。 5. 将预处理后的图像输入到模型中，...

def getitem(self, index): if self.args.cached: (label, _, image) = self.data[index] else: (label, _file) = self.file_indexes[index] image = self._load_rml(_file) n_label = self.classes.index(label) return torch.tensor(image).float(), torch.tensor(n_label).long()把这段代码基于pytorch改为基于mindspore

transform = py_transforms.Compose([ py_transforms.Resize((224, 224)), py_transforms.RandomHorizontalFlip(), py_transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) # 数据...

import torch import numpy as np from torchvision import datasets, models, transforms from torchvision import transforms from PIL import Image transform = transforms.Compose([ transforms.Resize((28, 28), interpolation=2), transforms.ToTensor() ] ) a=np.load('./original_crystal_2d_graphs/mp-170_copy1_opt.vasp_subst_O-Se_V-Bi.npy') img = a[0:3, :] #数组形式 im = Image.fromarray(img) # img = Image.open(im) img_ = transform(im).unsqueeze(0) #拓展维度 img_.show()

这段代码的作用是，导入了PyTorch、NumPy和torchvision等工具库，并指定了一组数据转换操作（修改为28x28尺寸并转换为张量格式）。然后，使用NumPy库读取了一个二维晶体图形的数据，并取出前三行作为图像数据。

解释代码：import os.path import torch import torch.nn as nn from torchvision import models, transforms from torch.autograd import Variable import numpy as np from PIL import Image features_dir = './features' # 存放特征的文件夹路径 img_path = "F:\\cfpg\\result\\conglin.jpg" # 图片路径 file_name = img_path.split('/')[-1] # 图片路径的最后一个/后面的名字 feature_path = os.path.join(features_dir, file_name + '.txt') # /后面的名字加txt transform1 = transforms.Compose([ # 串联多个图片变换的操作 transforms.Resize(256), # 缩放 transforms.CenterCrop(224), # 中心裁剪 transforms.ToTensor()] # 转换成Tensor ) img = Image.open(img_path) # 打开图片 img1 = transform1(img) # 对图片进行transform1的各种操作 # resnet18 = models.resnet18(pretrained = True) resnet50_feature_extractor = models.resnet50(pretrained=True) # 导入ResNet50的预训练模型 resnet50_feature_extractor.fc = nn.Linear(2048, 2048) # 重新定义最后一层 torch.nn.init.eye(resnet50_feature_extractor.fc.weight) # 将二维tensor初始化为单位矩阵 for param in resnet50_feature_extractor.parameters(): param.requires_grad = False # resnet152 = models.resnet152(pretrained = True) # densenet201 = models.densenet201(pretrained = True) x = Variable(torch.unsqueeze(img1, dim=0).float(), requires_grad=False) # y1 = resnet18(x) y = resnet50_feature_extractor(x) y = y.data.numpy() np.savetxt(feature_path, y, delimiter=',') # y3 = resnet152(x) # y4 = densenet201(x) y_ = np.loadtxt(feature_path, delimiter=',').reshape(1, 2048)

4. 定义一个transforms.Compose对象transform1，该对象串联多个图片变换的操作，包括缩放、中心裁剪、转换成Tensor等。 5. 使用PIL库中的Image.open函数打开指定路径的图片，然后对其进行transform1的各种操作，...

import torch import torch.nn as nn import torch.nn.functional as F import torchvision.transforms as transforms from PIL import Image # 加载图像 img = Image.open('2.jpg') # 对图像进行预处理，将其转换为模型所需的输入格式 transform = transforms.Compose([ transforms.Resize(256), transforms.CenterCrop(224), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) img_tensor = transform(img).unsqueeze(0) # 初始化模型并对图像进行特征提取 model = torch.hub.load('pytorch/vision:v0.6.0', 'resnet50', pretrained=True) features = model.conv1(img_tensor) features = model.bn1(features) features = model.relu(features) features = model.maxpool(features) features = model.layer1(features) features = model.layer2(features) features = model.layer3(features) features = model.layer4(features) # 将特征图还原回原始图像大小 upsample = nn.Upsample(scale_factor=32, mode='bilinear', align_corners=True) upsampled_features = upsample(features) # 显示原始图像和还原后的特征图 img.show() tensor_to_image = transforms.ToPILImage() upsampled_image = tensor_to_image(upsampled_features.squeeze(0).detach().cpu()) upsampled_image.show()，上述代码出现问题：ValueError: pic should not have > 4 channels. Got 2048 channels.

这个问题可能是因为在对特征图进行还原时，upsampled_features的通道数为2048，而ToPILImage()只能处理通道数为1、3或4的图像。解决方法是在还原特征图之前，将其通道数降为3，例如可以使用torch.mean将特征图...

import torch from torch import nn, optim import torchvision.transforms as transforms from torchvision import datasets from torch.utils.data import DataLoader from restnet18.restnet18 import RestNet18 # 用CIFAR-10 数据集进行实验 def main(): batchsz = 128 cifar_train = datasets.CIFAR10('cifar', True, transform=transforms.Compose([ transforms.Resize((32, 32)), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]), download=True) cifar_train = DataLoader(cifar_train, batch_size=batchsz, shuffle=True) cifar_test = datasets.CIFAR10('cifar', False, transform=transforms.Compose([ transforms.Resize((32, 32)), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]), download=True) cifar_test = DataLoader(cifar_test, batch_size=batchsz, shuffle=True) x, label = iter(cifar_train).next() print('x:', x.shape, 'label:', label.shape) device = torch.device('cuda') # model = Lenet5().to(device) model = RestNet18().to(device) criteon = nn.CrossEntropyLoss().to(device) optimizer = optim.Adam(model.parameters(), lr=1e-3) print(model) ———————————————— 逐行解释以上代码

然后通过transforms.Compose将多个数据预处理操作组合在一起，包括将图像大小调整为32x32像素、转换为张量格式、以及归一化处理。最后使用DataLoader将数据集包装成一个可迭代的数据加载器，设置批量大小为...

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