Insieme di immagini (dataset)

Iniziamo creando un Dataset di Torch per le immagini. Lo userai per esplorare i dati e, più avanti, per fornirli a un modello.

I dati di training per il task di classificazione delle nuvole sono salvati nella seguente struttura di directory:

clouds_train
  - cirriform clouds
    - 539cd1c356e9c14749988a12fdf6c515.jpg
    - ...
  - clear sky
  - cumulonimbus clouds
  - cumulus clouds
  - high cumuliform clouds
  - stratiform clouds
  - stratocumulus clouds

Ci sono sette cartelle dentro clouds_train, ognuna rappresenta un tipo di nuvola (o un cielo sereno). All'interno di ciascuna cartella si trovano i relativi file immagine.

I seguenti import sono già stati eseguiti per te:

from torchvision.datasets import ImageFolder
from torchvision import transforms

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Deep Learning intermedio con PyTorch

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Istruzioni dell'esercizio

Componi due trasformazioni: la prima per convertire l'immagine in un tensore, e la seconda per ridimensionarla a 128 per 128, assegnandole a train_transforms.
Usa ImageFolder per definire dataset_train, passandogli il percorso della directory dei dati ("clouds_train") e le trasformazioni definite in precedenza.

Esercizio pratico interattivo

Prova a risolvere questo esercizio completando il codice di esempio.

# Compose transformations
train_transforms = ____([
    transforms.____,
    transforms.____,
])

# Create Dataset using ImageFolder
dataset_train = ____(
    ____,
    transform=____,
)

Modifica ed esegui il codice

Questo esercizio fa parte del corso

Deep Learning intermedio con PyTorch

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Learn how to train neural networks in a robust way. In this chapter, you will use object-oriented programming to define PyTorch datasets and models and refresh your knowledge of training and evaluating neural networks. You will also get familiar with different optimizers and, finally, get to grips with various techniques that help mitigate the problems of unstable gradients so ubiquitous in neural nets training.

Exercise 1: PyTorch and object-oriented programming Exercise 2: PyTorch Dataset Exercise 3: PyTorch DataLoader Exercise 4: PyTorch Model Exercise 5: Optimizers, training, and evaluation Exercise 6: Training loop Exercise 7: Optimizers Exercise 8: Model evaluation Exercise 9: Vanishing and exploding gradients Exercise 10: Initialization and activation Exercise 11: Activations: ReLU vs. ELU Exercise 12: Batch Normalization

Train neural networks to solve image classification tasks. In this chapter, you will learn how to handle image data in PyTorch and get to grips with convolutional neural networks (CNNs). You will practice training and evaluating an image classifier while learning about how to improve the model performance with data augmentation.

Exercise 1: Gestire le immagini con PyTorch Exercise 2: Insieme di immagini (dataset)

Esercizio in corso

Exercise 3: Data augmentation Exercise 4: Data augmentation in PyTorch Exercise 5: Convolutional Neural Networks Exercise 6: Il livello convoluzionale Exercise 7: Costruire reti convoluzionali Exercise 8: Addestrare i classificatori di immagini Exercise 9: Scelta delle aumentazioni Exercise 10: Insieme di dati con augmentations Exercise 11: Ciclo di training del classificatore di immagini Exercise 12: Valutare i classificatori di immagini Exercise 13: Valutazione di un modello multi-classe Exercise 14: Analizzare le metriche per classe

Build and train recurrent neural networks (RNNs) for processing sequential data such as time series, text, or audio. You will learn about the two most popular recurrent architectures, Long-Short Term Memory (LSTM) and Gated Recurrent Unit (GRU) networks, as well as how to prepare sequential data for model training. You will practice your skills by training and evaluating a recurrent model for predicting electricity consumption.

Exercise 1: Handling sequences with PyTorch Exercise 2: Generating sequences Exercise 3: Sequential Dataset Exercise 4: Recurrent Neural Networks Exercise 5: Sequential architectures Exercise 6: Building a forecasting RNN Exercise 7: LSTM and GRU cells Exercise 8: RNN vs. LSTM vs. GRU Exercise 9: LSTM network Exercise 10: GRU network Exercise 11: Training and evaluating RNNs Exercise 12: RNN training loop Exercise 13: Evaluating forecasting models

Build multi-input and multi-output models, demonstrating how they can handle tasks requiring more than one input or generating multiple outputs. You will explore how to design and train these models using PyTorch and delve into the crucial topic of loss weighting in multi-output models. This involves understanding how to balance the importance of different tasks when training a model to perform multiple tasks simultaneously.

Exercise 1: Multi-input models Exercise 2: Two-input dataset Exercise 3: Two-input model Exercise 4: Training two-input model Exercise 5: Multi-output models Exercise 6: Two-output Dataset and DataLoader Exercise 7: Two-output model architecture Exercise 8: Training multi-output models Exercise 9: Evaluation of multi-output models and loss weighting Exercise 10: Multi-output model evaluation Exercise 11: Loss weighting Exercise 12: Wrap-up