transforms.RandomCrop((img_h, img_w)) raise ValueError(empty range for randrange)(%d,%d, %d)

本文详细解析了在使用PyTorch进行图像预处理时遇到的随机裁剪越界错误,通过调整transforms.RandomCrop参数解决了ValueError异常,并提供正确的数值范围选取策略。

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问题

  File "E:/wj-lab/expStad/train.py", line 446, in <module>
    losses=train(epoch)
  File "E:/wj-lab/expStad/train.py", line 239, in train
    for batch_idx, (input1, input2, label1, label2) in enumerate(tqdm(trainloader)):

  File "D:\Anaconda3\envs\python35\lib\site-packages\tqdm\_tqdm.py", line 979, in __iter__
    for obj in iterable:
  File "D:\Anaconda3\envs\python35\lib\site-packages\torch\utils\data\dataloader.py", line 264, in __next__
    batch = self.collate_fn([self.dataset[i] for i in indices])

  File "D:\Anaconda3\envs\python35\lib\site-packages\torch\utils\data\dataloader.py", line 264, in <listcomp>
    batch = self.collate_fn([self.dataset[i] for i in indices])

  File "E:\wj-lab\expStad\data_loader.py", line 38, in __getitem__
    img1 = self.transform(img1)

  File "D:\Anaconda3\envs\python35\lib\site-packages\torchvision\transforms\transforms.py", line 49, in __call__
    img = t(img)
  File "D:\Anaconda3\envs\python35\lib\site-packages\torchvision\transforms\transforms.py", line 421, in __call__
    i, j, h, w = self.get_params(img, self.size)

  File "D:\Anaconda3\envs\python35\lib\site-packages\torchvision\transforms\transforms.py", line 400, in get_params
    j = random.randint(0, w - tw)
  File "D:\Anaconda3\envs\python35\lib\random.py", line 227, in randint
    return self.randrange(a, b+1)
  File "D:\Anaconda3\envs\python35\lib\random.py", line 205, in randrange
    
raise ValueError("empty range for randrange() (%d,%d, %d)" % (istart, istop, width))

ValueError: empty range for randrange() (0,-59, -59)

出错源码

       normalize=transforms.Normalize(mean=[0.485,0.456,0.406], std=[0.229,0.224,0.225]) 
       transform_train = transforms.Compose([ 
                      transforms.ToPILImage(), 
                      transforms.Pad(10),
                      transforms.RandomCrop((348, 204)),
                      transforms.RandomHorizontalFlip(), 
                      transforms.ToTensor(),
                      normalize, ])

原因

随机裁剪越界,transforms.RandomCrop 调用 random.randint(a,b),生成的随机整数n取值范围(a<=n<=b),如果a=b,则n=a,如果a>b,就会报错

解决办法

注意到 ValueError: empty range for randrange() (0,-59, -59)   凡是出现类似错误的,都是调试数值范围

故 正确取值范围极限在  348-59-1=288      204-59-1=144    即最大取值范围在(288,144)

 transforms.RandomCrop((288, 144))

 normalize=transforms.Normalize(mean=[0.485,0.456,0.406], std=[0.229,0.224,0.225]) 
       transform_train = transforms.Compose([ 
                      transforms.ToPILImage(), 
                      transforms.Pad(10),
                      transforms.RandomCrop((288, 144)), # 修改处
                      transforms.RandomHorizontalFlip(), 
                      transforms.ToTensor(),
                      normalize, ])

 

import os # 在代码最开头添加以下环境变量(放在所有import之前) os.environ["CUDA_VISIBLE_DEVICES"] = "0" # 明确指定GPU os.environ["FLAGS_cudnn_deterministic"] = "1" # 固定cuDNN行为 os.environ["FLAGS_conv_workspace_size_limit"] = "1024" # 限制cuDNN工作空间 import paddle import paddle.nn as nn from paddle.vision import transforms, datasets from paddle.io import DataLoader import numpy as np import os import cv2 from datetime import datetime from collections import Counter import warnings import sys warnings.filterwarnings('ignore') # 情绪类别 emotions = ['angry', 'disgust', 'fear', 'happy', 'neutral', 'sad', 'surprise'] class EmotionCNN(nn.Layer): def __init__(self, num_classes=7): super(EmotionCNN, self).__init__() self.features = nn.Sequential( nn.Conv2D(3, 64, kernel_size=3, padding=1), nn.BatchNorm2D(64), nn.ReLU(), nn.MaxPool2D(2), # 64x64 nn.Conv2D(64, 128, kernel_size=3, padding=1), nn.BatchNorm2D(128), nn.ReLU(), nn.MaxPool2D(2), # 32x32 nn.Conv2D(128, 256, kernel_size=3, padding=1), nn.BatchNorm2D(256), nn.ReLU(), nn.MaxPool2D(2), # 16x16 nn.Conv2D(256, 512, kernel_size=3, padding=1), nn.BatchNorm2D(512), nn.ReLU(), nn.MaxPool2D(2), # 8x8 ) self.classifier = nn.Sequential( nn.Linear(512 * 8 * 8, 1024), nn.ReLU(), nn.Dropout(0.5), nn.Linear(1024, num_classes) ) def forward(self, x): x = self.features(x) x = paddle.flatten(x, 1) x = self.classifier(x) return x def image_loader(path): try: img = cv2.imread(path) if img is None: raise ValueError(f"无法读取图像: {path}") img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB) img = cv2.resize(img, (128, 128)) # 确保尺寸一致 return img except Exception as e: print(f"加载图像错误: {path}, 错误: {str(e)}") return np.zeros((128, 128, 3), dtype=np.uint8) def get_class_distribution(dataset): class_counts = Counter() for _, label in dataset.samples: class_counts[label] += 1 return class_counts def check_data_consistency(dataset): """检查数据集中所有图像的尺寸是否一致""" sizes = set() for path, _ in dataset.samples: img = image_loader(path) sizes.add(img.shape) return sizes def train_model(data_dir, model_save_path): # 记录开始时间 start_time = datetime.now() print(f"训练开始时间: {start_time.strftime('%Y-%m-%d %H:%M:%S')}") # 训练参数 num_epochs = 20 batch_size = 32 learning_rate = 0.001 weight_decay = 1e-4 patience = 3 # 数据预处理和增强 transform = transforms.Compose([ transforms.Resize((128, 128)), transforms.RandomHorizontalFlip(), transforms.RandomRotation(10), transforms.ColorJitter(brightness=0.2, contrast=0.2), transforms.ToTensor(), transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]) ]) # 加载数据集 try: train_dataset = datasets.DatasetFolder( os.path.join(data_dir, 'train'), loader=image_loader, extensions=['.jpg', '.jpeg', '.png'], transform=transform ) val_dataset = datasets.DatasetFolder( os.path.join(data_dir, 'val'), loader=image_loader, extensions=['.jpg', '.jpeg', '.png'], transform=transform ) # 打印类别到标签的映射 print("\n类别到标签的映射:") print(train_dataset.class_to_idx) # 验证标签范围 for i, (_, label) in enumerate(train_dataset.samples[:10]): print(f"样本 {i}: 路径={train_dataset.samples[i][0]}, 标签={label}") except Exception as e: print(f"加载数据集时出错: {str(e)}") return # 加载数据集后添加检查 print("\n验证数据集标签范围...") all_labels = [label for _, label in train_dataset.samples + val_dataset.samples] print(f"标签最小值: {min(all_labels)}, 最大值: {max(all_labels)}") invalid_labels = [l for l in all_labels if l < 0 or l >= len(emotions)] if invalid_labels: print(f"发现无效标签: {set(invalid_labels)}") print("请检查数据集目录结构,确保只有以下目录:") print(emotions) return # 在加载数据集后打印更详细的类别信息 print("\n类别到标签的映射:") print(train_dataset.class_to_idx) print("确保映射如下:") for i, emotion in enumerate(emotions): print(f"{emotion}: {i}") # 检查数据尺寸一致性 train_sizes = check_data_consistency(train_dataset) val_sizes = check_data_consistency(val_dataset) print(f"\n训练集图像尺寸: {train_sizes}") print(f"验证集图像尺寸: {val_sizes}") # 打印数据分布 train_counts = get_class_distribution(train_dataset) val_counts = get_class_distribution(val_dataset) print("\n数据分布统计:") for i, emotion in enumerate(emotions): print(f"{emotion}: 训练集 {train_counts[i]}张, 验证集 {val_counts[i]}张") # 自定义collate_fn函数,处理数据加载 def collate_fn(batch): # 过滤掉无效数据 valid_batch = [] for x, y in batch: if x is not None and 0 <= y < len(emotions): # 使用len(emotions)而不是硬编码7 valid_batch.append((x, y)) if len(valid_batch) == 0: return None, None # 转换为paddle tensor images = paddle.stack([paddle.to_tensor(x) for x, y in valid_batch]) labels = paddle.to_tensor([y for x, y in valid_batch], dtype='int64') return images, labels # 创建数据加载器 train_loader = DataLoader( train_dataset, batch_size=batch_size, shuffle=True, num_workers=0, collate_fn=collate_fn ) val_loader = DataLoader( val_dataset, batch_size=batch_size, num_workers=0, collate_fn=collate_fn ) # 初始化模型 model = EmotionCNN(num_classes=7) # 设置GPU设备 if paddle.is_compiled_with_cuda(): paddle.set_device('gpu') print("模型将在GPU上运行") else: paddle.set_device('cpu') print("模型将在CPU上运行") # GPU测试 try: test_input = paddle.randn([1, 3, 128, 128]) if paddle.is_compiled_with_cuda(): test_input = test_input.cuda() output = model(test_input) print(f"\nGPU测试前向传播成功! 输出形状: {output.shape}, 设备: {output.place}") except Exception as e: print(f"\nGPU测试前向传播失败: {str(e)}") print("CUDA是否可用:", paddle.is_compiled_with_cuda()) print("当前设备:", paddle.get_device()) return # 打印模型结构 print("\n模型结构:") print(model) model.train() # 损失函数和优化器 criterion = nn.CrossEntropyLoss() optimizer = paddle.optimizer.Adam( learning_rate=learning_rate, parameters=model.parameters(), weight_decay=weight_decay ) # 训练循环 best_val_acc = 0.0 no_improve = 0 print(f"\n训练数据量: {len(train_dataset)}, 验证数据量: {len(val_dataset)}") print(f"训练参数: 学习率={learning_rate}, 批量大小={batch_size}, 训练轮次={num_epochs}") print("开始训练...\n") for epoch in range(num_epochs): try: model.train() running_loss = 0.0 correct = 0 total = 0 for batch_idx, (inputs, labels) in enumerate(train_loader): # 跳过无效批次 if inputs is None or labels is None: print("跳过无效批次") continue # 确保输入数据格式正确 if inputs.shape[1] != 3 or inputs.shape[2] != 128 or inputs.shape[3] != 128: print(f"无效的输入形状: {inputs.shape}, 跳过此batch") continue # 验证标签值 if paddle.any(labels < 0) or paddle.any(labels >= 7): print(f"无效的标签值: {labels}, 跳过此batch") continue optimizer.clear_grad() outputs = model(inputs) # 确保标签是int64类型 labels = paddle.cast(labels, 'int64') loss = criterion(outputs, labels) loss.backward() optimizer.step() running_loss += loss.item() # 计算准确率 predicted = paddle.argmax(outputs, axis=1) total += labels.shape[0] correct += paddle.sum(predicted == labels).item() # 每10个batch打印一次 if batch_idx % 10 == 9: avg_loss = running_loss / 10 current_acc = 100. * correct / total print(f'Epoch: {epoch+1}/{num_epochs}, Batch: {batch_idx+1}, ' f'Loss: {avg_loss:.4f}, Acc: {current_acc:.2f}%') running_loss = 0.0 except Exception as e: print(f"训练过程中发生错误: {str(e)}") print("尝试清理CUDA缓存并继续...") paddle.device.cuda.empty_cache() continue # 计算训练准确率 train_acc = 100. * correct / total train_loss = running_loss / len(train_loader) print(f'Epoch {epoch+1} 训练准确率: {train_acc:.2f}%, 训练损失: {train_loss:.4f}') # 验证 model.eval() val_correct = 0 val_total = 0 val_loss = 0.0 with paddle.no_grad(): for inputs, labels in val_loader: # 跳过无效批次 if inputs is None or labels is None: continue # 确保输入数据格式正确 if inputs.shape[1] != 3 or inputs.shape[2] != 128 or inputs.shape[3] != 128: continue outputs = model(inputs) labels = paddle.cast(labels, 'int64') loss = criterion(outputs, labels) val_loss += loss.item() predicted = paddle.argmax(outputs, axis=1) val_total += labels.shape[0] val_correct += paddle.sum(predicted == labels).item() if val_total == 0: print("验证集无有效数据!") break val_acc = 100. * val_correct / val_total avg_val_loss = val_loss / len(val_loader) print(f'Epoch {epoch+1} 验证准确率: {val_acc:.2f}%, 验证损失: {avg_val_loss:.4f}') # 早停机制和模型保存 if val_acc > best_val_acc: best_val_acc = val_acc no_improve = 0 paddle.save(model.state_dict(), model_save_path + '.pdparams') paddle.save(optimizer.state_dict(), model_save_path + '.pdopt') print(f'模型已保存,验证准确率: {best_val_acc:.2f}%') else: no_improve += 1 if no_improve >= patience: print(f"验证集准确率{patience}轮未提升,提前停止训练") break # 计算总训练时间 end_time = datetime.now() total_time = end_time - start_time print(f"\n训练完成! 总耗时: {total_time}") print(f"最佳验证准确率: {best_val_acc:.2f}%") if __name__ == '__main__': # 数据路径 data_dir = 'data' model_save_path = 'emotion_model' # 检查并创建必要的目录 os.makedirs('models', exist_ok=True) # 检查数据目录是否存在 required_dirs = ['train', 'val'] for dir_name in required_dirs: dir_path = os.path.join(data_dir, dir_name) if not os.path.exists(dir_path): print(f"错误: 目录不存在 - {dir_path}") exit(1) # 检查每个情绪类别目录 for emotion in emotions: emotion_path = os.path.join(dir_path, emotion) if not os.path.exists(emotion_path): print(f"警告: 情绪目录不存在 - {emotion_path}") # 检查GPU可用性 if paddle.is_compiled_with_cuda(): paddle.set_device('gpu') print("使用GPU进行训练") else: paddle.set_device('cpu') print("使用CPU进行训练") # 开始训练 train_model(data_dir, model_save_path)此代码运行后是无效的标签值: Tensor(shape=[32], dtype=int64, place=Place(gpu:0), stop_gradient=True, [1, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7]), 跳过此batch,请指出可能出现的问题并解决
06-21
# 完整训练脚本(分类任务) import torch from torchvision import models, transforms, datasets # 数据加载 train_transform = transforms.Compose([...]) # 同上 train_set = datasets.ImageFolder('D:/YOLOV8/ultralytics-main/datasets/lytdatasets/images', transform=train_transform) train_loader = torch.utils.data.DataLoader(train_set, batch_size=32, shuffle=True) # 模型初始化 model = models.resnet18(pretrained=True) model.fc = torch.nn.Linear(512, 3) # 假设3类缺陷 # 训练配置 device = torch.device('cuda' if torch.cuda.is_available() else 'cpu') model.to(device) criterion = torch.nn.CrossEntropyLoss() optimizer = torch.optim.Adam(model.parameters(), lr=1e-4) # 训练循环 for epoch in range(20): model.train() for inputs, labels in train_loader: inputs, labels = inputs.to(device), labels.to(device) outputs = model(inputs) loss = criterion(outputs, labels) optimizer.zero_grad() loss.backward() optimizer.step() print(f'Epoch {epoch+1}, Loss: {loss.item():.4f}')D:\anaconda\envs\yolo8\python.exe D:/YOLOV8/ultralytics-main/datasets/classes.py Traceback (most recent call last): File "D:/YOLOV8/ultralytics-main/datasets/classes.py", line 7, in <module> train_set = datasets.ImageFolder('D:/YOLOV8/ultralytics-main/datasets/lytdatasets/images', transform=train_transform) File "D:\anaconda\envs\yolo8\lib\site-packages\torchvision\datasets\folder.py", line 310, in __init__ super(ImageFolder, self).__init__(root, loader, IMG_EXTENSIONS if is_valid_file is None else None, File "D:\anaconda\envs\yolo8\lib\site-packages\torchvision\datasets\folder.py", line 145, in __init__ classes, class_to_idx = self.find_classes(self.root) File "D:\anaconda\envs\yolo8\lib\site-packages\torchvision\datasets\folder.py", line 221, in find_classes return find_classes(directory) File "D:\anaconda\envs\yolo8\lib\site-packages\torchvision\datasets\folder.py", line 42, in find_classes raise FileNotFoundError(f"Couldn't find any class folder in {directory}.") F
03-16
<think>我们正在处理一个关于将RGB图像转换为灰度图像的问题。用户提到了使用`torchvision.transforms.functional.rgb_to_grayscale`方法。根据引用[3]中的信息,Grayscale类也是用来将图像转换为灰度图的,它内部调用了`F.to_grayscale`(即`torchvision.transforms.functional.to_grayscale`)。注意,在torchvision中,`rgb_to_grayscale`和`to_grayscale`可能是同一个函数,但我们需要确认。 根据用户的问题,我们直接使用`torchvision.transforms.functional.rgb_to_grayscale`。这个函数的输入应该是RGB图像(PIL Image或Tensor),并返回灰度图像。 函数的使用方法: - 如果输入是PIL Image,则返回PIL Image。 - 如果输入是Tensor,则返回Tensor。 注意:该函数默认输出单通道灰度图像。如果我们想要三通道的灰度图像(每个通道的值相同),则需要在转换后复制通道。 但是,用户没有明确说明输出通道数。根据引用[3],Grayscale类可以指定输出通道数为1或3。因此,我们也可以使用Grayscale类来实现。 不过用户明确要求使用`torchvision.transforms.functional.rgb_to_grayscale`,所以我们直接使用这个函数。 步骤: 1. 导入必要的库:`torchvision.transforms.functional`和`PIL.Image`。 2. 使用`Image.open`打开图像。 3. 调用`rgb_to_grayscale`函数进行转换。 4. 保存或显示转换后的图像。 注意:转换后的图像是单通道的,如果我们需要三通道,可以再使用`convert('RGB')`将其转换为三通道(但每个通道的值相同),或者使用`torchvision.transforms.functional.to_grayscale`时指定输出通道数?但查看文档,`rgb_to_grayscale`函数没有指定输出通道数的参数,它总是返回单通道。所以如果我们想要三通道,需要自己处理。 根据引用[3],Grayscale类在调用时可以通过参数`num_output_channels`指定输出1或3个通道。如果我们使用`rgb_to_grayscale`,它只返回1个通道,那么我们可以通过将同一个通道复制三次来得到三通道的灰度图像。 因此,我们有两种方法: 方法一:使用`rgb_to_grayscale`得到单通道图像,然后将其转换为三通道(如果需要)。 方法二:使用`Grayscale`类,并指定`num_output_channels=1`或`3`。 用户要求使用`rgb_to_grayscale`,所以我们先按单通道输出,然后如果需要三通道,再额外处理。 示例代码: ```python from torchvision.transforms.functional import rgb_to_grayscale from PIL import Image # 打开RGB图像 img = Image.open('input_rgb.jpg') # 将PIL Image转换为Tensor?注意:rgb_to_grayscale可以接受PIL Image或Tensor # 但根据文档,该函数同时支持PIL Image和Tensor。不过,在torchvision.transforms.functional中,对于PIL Image和Tensor有不同的处理分支。 # 直接使用PIL Image gray_img = rgb_to_grayscale(img) # 返回的是单通道的PIL Image # 保存单通道灰度图像 gray_img.save('gray_image.jpg') # 如果需要三通道的灰度图像(即三个通道的值相同),可以转换模式 gray_img_rgb = gray_img.convert('RGB') gray_img_rgb.save('gray_image_rgb.jpg') ``` 注意:单通道的灰度图像保存为jpg时,有些软件可能显示不正常(因为jpg通常支持三通道)。所以,如果我们需要三通道的灰度图,最好转换为'RGB'模式。 另外,我们也可以使用`Grayscale`类来实现,这样更简洁,特别是当我们需要三通道时: ```python from torchvision.transforms import Grayscale from PIL import Image img = Image.open('input_rgb.jpg') # 创建转换对象,指定输出通道数 transform = Grayscale(num_output_channels=3) # 输出三通道灰度图 gray_img_rgb = transform(img) gray_img_rgb.save('gray_image_rgb.jpg') ``` 但是,用户要求使用`rgb_to_grayscale`,所以我们主要展示第一种方法。 现在,生成相关问题: 1. 使用`rgb_to_grayscale`转换后的灰度图像与使用`Grayscale`类转换的有什么区别? 2. 在PyTorch中处理图像时,使用PIL Image和Tensor有什么区别? 3. 如何将单通道的灰度图像转换为三通道的灰度图像?</think>### 将RGB图像转换为灰度图像的方法 在PyTorch的`torchvision.transforms.functional`模块中,可以使用`rgb_to_grayscale`函数将RGB图像转换为灰度图像。以下是具体实现步骤: #### 1. 导入必要库 ```python from torchvision.transforms.functional import rgb_to_grayscale from PIL import Image import torch ``` #### 2. 图像加载与转换 ```python # 加载RGB图像 img = Image.open('input_rgb.jpg') # RGB格式的PIL图像 # 方法1:直接转换PIL图像 gray_pil = rgb_to_grayscale(img) # 返回单通道PIL图像 # 方法2:转换Tensor图像(推荐用于深度学习流程) img_tensor = torch.tensor(np.array(img)).permute(2, 0, 1) # 转为CxHxW格式 gray_tensor = rgb_to_grayscale(img_tensor) # 返回[1, H, W]张量 ``` #### 3. 关键参数说明 - **输入要求**: - 支持PIL Image (RGB模式) 或Tensor (CxHxW格式) - Tensor输入时要求值范围[0,1]或[0,255][^2] - **输出特性**: - 始终返回单通道图像 - 遵循ITU-R BT.601转换标准:$Y = 0.299R + 0.587G + 0.114B$ - **与Grayscale类的区别**: `rgb_to_grayscale`是函数式实现,而`transforms.Grayscale`是可组合的转换类,两者底层实现相同[^3] #### 4. 完整示例 ```python from torchvision.transforms.functional import rgb_to_grayscale from PIL import Image # 加载图像 rgb_image = Image.open('example.jpg').convert('RGB') # 转换为灰度 gray_image = rgb_to_grayscale(rgb_image) # 保存结果 gray_image.save('output_gray.jpg') ``` #### 5. 注意事项 1. 输入**必须为三通道**RGB图像 2. 输出单通道图像可直接保存为JPEG/PNG 3. 若需三通道灰度输出(R=G=B),可后续处理: ```python gray_rgb = gray_image.convert('RGB') # 转为三通道 ``` 4. 与`ColorJitter`等转换组合使用时,建议使用`transforms.Compose`[^1]
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