Short answer
Deep learning is machine learning with multi-layer neural networks that learn hierarchical representations—especially strong for images, audio, and language.
Why it matters
Transformers, diffusion image models, and speech systems are deep learning stacks. Knowing the paradigm clarifies hardware needs and failure modes.
Diagram
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Each layer builds slightly more abstract features—from edges to objects, or from tokens to phrases.
Examples
Image classification with convolutional networks
A convolutional neural network trained on labeled photos can assign categories such as “bridge” or “coastal cliff.” Early layers respond to edges and color transitions; deeper layers respond to larger shapes. Data augmentation (crops, flips) improves robustness to common photographic variation.
Speech recognition acoustic models
Deep networks map short windows of audio features to phonetic or subword units. End-to-end architectures can learn directly from waveforms or spectrograms to text tokens, improving recognition when trained on diverse speakers and acoustic environments.
FAQ
When should I choose deep learning over classical ML?
Deep learning tends to excel with large datasets and unstructured inputs such as images, audio, and raw text. For smaller tabular problems, well-tuned classical models are often competitive and easier to operate. Start with a strong baseline and escalate complexity when evidence justifies it.
What is pretraining?
Pretraining is training a model on a broad dataset (often with self-supervised objectives) to learn general representations, then adapting it to downstream tasks via fine-tuning or prompting. It amortizes expensive representation learning across many uses.
Related glossary terms
- Computer vision — AI techniques that extract meaningful information from images and video, such as objects, text, depth, or motion.
- Deep learning — Machine learning with multi-layer neural networks that learn hierarchical representations from large datasets.
- Fine-tuning — Additional training that adapts a pretrained model to a narrower task, domain, or preferred behavior using specialized…
- Machine learning — A family of methods that improve model performance by learning patterns from data instead of relying only on hand-coded…
- Neural network — A model made of layered interconnected units that transform inputs through weighted connections and nonlinear…
- Training data — The examples used to fit a model’s parameters, including inputs and any labels or supervisory signals required by the…
Sources
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Deep Learning (online textbook)
Goodfellow, Bengio, CourvilleWidely used academic reference covering foundations of deep neural networks.
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DeepLearning.AI blog
DeepLearning.AIEducational commentary on deep learning research and practice.