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

Pytoch之torchvision.transforms图像变换实例

今天小编就为大家分享一篇Pytoch之torchvision.transforms图像变换实例，具有很好的参考价值，希望对大家有所帮助。一起跟随小编过来看看吧

导入FashionMNIST数据集时报错module ‘torchvision.datasets’ has no attribute ‘FashionMNIS’

在阅读动手学深度学习-pytorch的过程中，发现...train=True, download=True, transform=transforms.ToTensor()) mnist_test = torchvision.datasets.FashionMNIST(root='~/Datasets/FashionMNIST', train=False, downl

opencv_transforms_torchvision:在Torchvision中进行转换的opencv重新实现

opencv_torchvision_transform 这是基于Opencv的torchvision“ transforms”的重写。所有功能仅取决于cv2和pytorch（无PIL）。如，cv2比PIL快三倍。转换中的大多数函数都被重新实现，除了：在原始版本中已弃...

# 定义数据预处理 transform_train = transforms.Compose([ transforms.RandomCrop(224), transforms.RandomHorizontalFlip(), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) transform_val = transforms.Compose([ transforms.CenterCrop(224), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) # 定义数据集 train_data = torchvision.datasets.ImageFolder(os.path.join(data_dir, 'train'), transform=transform_train) val_data = torchvision.datasets.ImageFolder(os.path.join(data_dir, 'val'), transform=transform_val)，这段代码是什么意思

transform_val 定义了验证集的预处理操作，包括将图像中心裁剪为 224x224 大小、将图像转换为张量格式，以及按照 ImageNet 数据集的均值和标准差对图像进行标准化。接着，使用 PyTorch 中的 ImageFolder 类构建...

# 定义数据集 train_data = torchvision.datasets.ImageFolder(os.path.join(data_dir, 'train'), transform=transform_train) val_data = torchvision.datasets.ImageFolder(os.path.join(data_dir, 'val'), transform=transform_val) # 定义数据加载器 train_loader = torch.utils.data.DataLoader(train_data, batch_size=32, shuffle=True, num_workers=4) val_loader = torch.utils.data.DataLoader(val_data, batch_size=32, shuffle=False, num_workers=4)，好像并没有按照一定的比例你分割数据集

确实，这段代码没有明确地按照一定的比例...然后我们通过计算每个类别子文件夹下的图片数量，来确定需要将多少张图片移动到验证集中。最后，我们使用 datasets.ImageFolder() 类来读取数据，并且定义了数据加载器。

data_transform = transforms.Compose

在这个例子中，我们首先将图像大小重置为 $256 \times 256$，然后对其进行中心裁剪，裁剪后的大小为 $224 \times 224$。接着，我们将图像数据转换为张量，并进行了标准化处理，使其在每个通道上的均值为0，方差为1。...

val_transform = transforms.Compose([

train_transform = transforms.Compose([ transforms.RandomResizedCrop(224), transforms.RandomHorizontalFlip(), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0....

# 定义数据集路径和标签 data_dir = "D:/wjd" # 数据集路径 labels = ['Ag', 'Al', 'Au', 'Cu', 'W', 'V', 'Mo', 'Ta'] # 标签 # 将数据集按照 80% - 20% 的比例划分为训练集和验证集 train_dir = os.path.join(data_dir, 'train') val_dir = os.path.join(data_dir, 'val') if not os.path.exists(val_dir): os.makedirs(train_dir) os.makedirs(val_dir) # 遍历每个标签的文件夹 for label in labels: label_dir = os.path.join(data_dir, label) images = os.listdir(label_dir) random.shuffle(images) # 随机打乱图像顺序 # 划分训练集和验证集 split_index = int(0.8 * len(images)) train_images = images[:split_index] val_images = images[split_index:] # 将训练集和验证集图像复制到对应的文件夹中 for image in train_images: src_path = os.path.join(label_dir, image) dst_path = os.path.join(train_dir, label, image) os.makedirs(os.path.dirname(dst_path), exist_ok=True) # 确保目标文件夹存在 shutil.copy(src_path, dst_path) for image in val_images: src_path = os.path.join(label_dir, image) dst_path = os.path.join(val_dir, label, image) os.makedirs(os.path.dirname(dst_path), exist_ok=True) # 确保目标文件夹存在 shutil.copy(src_path, dst_path) #print("数据集已成功划分为训练集和验证集。") # 定义数据预处理 transform_train = transforms.Compose([ transforms.RandomCrop(224), transforms.RandomHorizontalFlip(), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) transform_val = transforms.Compose([ transforms.CenterCrop(224), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) # 定义数据集 train_data = datasets.ImageFolder(train_dir, transform=transform) val_data = datasets.ImageFolder(val_dir, transform=transform)，这里出现了错误

应该将 transform 改为 transform_train 或 transform_val，因为在定义数据集时需要指定数据的预处理方式，而这些预处理方式已经通过 transform_train 和 transform_val 变量进行定义。因此，你需要将最后...

torchvision.transforms.CenterCrop()如何用于数据增强

在这个例子中，我们首先使用torchvision.transforms.CenterCrop()函数从图像的中心裁剪一个大小为224*224的图像，然后使用torchvision.transforms.RandomHorizontalFlip()函数以50%的概率随机水平翻转图像。...

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()

3.将图像进行预处理，包括图像尺寸的调整、中心裁剪、像素归一化等操作。 4.将处理后的图像输入模型进行分类预测，打印输出预测结果。其中，模型的具体实现没有在这段代码中给出，可以通过调用Test_model类中的...

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...

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...

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，...

这是对单个文件进行预测“import os import json import torch from PIL import Image from torchvision import transforms import matplotlib.pyplot as plt from model import convnext_tiny as create_model def main(): device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu") print(f"using {device} device.") num_classes = 5 img_size = 224 data_transform = transforms.Compose( [transforms.Resize(int(img_size * 1.14)), transforms.CenterCrop(img_size), transforms.ToTensor(), transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])]) # load image img_path = "../tulip.jpg" assert os.path.exists(img_path), "file: '{}' dose not exist.".format(img_path) img = Image.open(img_path) plt.imshow(img) # [N, C, H, W] img = data_transform(img) # expand batch dimension img = torch.unsqueeze(img, dim=0) # read class_indict json_path = './class_indices.json' assert os.path.exists(json_path), "file: '{}' dose not exist.".format(json_path) with open(json_path, "r") as f: class_indict = json.load(f) # create model model = create_model(num_classes=num_classes).to(device) # load model weights model_weight_path = "./weights/best_model.pth" model.load_state_dict(torch.load(model_weight_path, map_location=device)) model.eval() with torch.no_grad(): # predict class output = torch.squeeze(model(img.to(device))).cpu() predict = torch.softmax(output, dim=0) predict_cla = torch.argmax(predict).numpy() print_res = "class: {} prob: {:.3}".format(class_indict[str(predict_cla)], predict[predict_cla].numpy()) plt.title(print_res) for i in range(len(predict)): print("class: {:10} prob: {:.3}".format(class_indict[str(i)], predict[i].numpy())) plt.show() if name == 'main': main()”，改为对指定文件夹下的左右文件进行预测，并绘制混淆矩阵

好的，你的问题是如何将上述代码修改为对指定文件夹下的所有文件进行预测，并绘制混淆矩阵。要实现这个功能，你需要进行以下几个步骤： 1. 导入必要的包： python import os import json import torch ...

self.transform = transforms.Compose

transforms.CenterCrop(224), # 中心裁剪为224x224 transforms.ToTensor(), # 转换为张量 transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) # 标准化 ]) # 在数据集上应用预处理...

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]) ]) # ...

为以下每句代码做注释：import torch from model import resnet152 from PIL import Image from torchvision import transforms import matplotlib.pyplot as plt import json device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu") data_transform = transforms.Compose( [transforms.Resize(256), transforms.CenterCrop(224), transforms.ToTensor(), transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])]) img = Image.open("./huanglongbing.JPG") plt.imshow(img) img = data_transform(img) img = torch.unsqueeze(img, dim=0) try: json_file = open('./class_indices.json', 'r') class_indict = json.load(json_file) except Exception as e: print(e) exit(-1) model = resnet152(num_classes=38) model_weight_path = "./resNet152.pth" model.load_state_dict(torch.load(model_weight_path, map_location=device)) model.eval() with torch.no_grad(): output = torch.squeeze(model(img)) predict = torch.softmax(output, dim=0) predict_cla = torch.argmax(predict).numpy() print(class_indict[str(predict_cla)], predict[predict_cla].numpy()) plt.show()

# 定义数据预处理的步骤，包括图片的resize、中心裁剪、转换为张量、以及标准化 data_transform = transforms.Compose( [transforms.Resize(256), transforms.CenterCrop(224), transforms.ToTensor(), ...

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

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 类将图像数据转换为 torch.Tensor 类型，并将像素值归一化到 [0, 1] 区间。如果需要对图像进行标准化，...

为以下每句代码做注释：device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu") data_transform = transforms.Compose( [transforms.Resize(256), transforms.CenterCrop(224), transforms.ToTensor(), transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])]) img = Image.open("./huanglongbing.JPG") plt.imshow(img) img = data_transform(img) img = torch.unsqueeze(img, dim=0) try: json_file = open('./class_indices.json', 'r') class_indict = json.load(json_file) except Exception as e: print(e) exit(-1) model = resnet152(num_classes=38) model_weight_path = "./resNet152.pth" model.load_state_dict(torch.load(model_weight_path, map_location=device)) model.eval() with torch.no_grad(): output = torch.squeeze(model(img)) predict = torch.softmax(output, dim=0) predict_cla = torch.argmax(predict).numpy() print(class_indict[str(predict_cla)], predict[predict_cla].numpy()) plt.show()

data_transform = transforms.Compose( [transforms.Resize(256), transforms.CenterCrop(224), transforms.ToTensor(), transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])] ) # 打开图像...

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