Artificial Intelligence is happening in many areas. You might be wondering how machines can perform tasks similar to humans. Have you ever wondered how Google can translate entire paragraphs from one language to another in milliseconds? How Netflix and YouTube can provide good recommendations? Or how self-driving cars are possible?
All these innovations are products of deep learning and artificial neural networks. Deep learning is a subfield of machine learning that deals with algorithms inspired by the structure and function of the brain, known as artificial neural networks. In this article, we explain what deep learning is, what it is used for, and how it works. If you are looking for books to learn more about deep learning, you can take a look at this list. Happy reading!
What is Deep Learning?

Deep learning is a type of machine learning that uses multi-layered neural networks called deep neural networks, inspired by the human brain’s structure and function.
Imagine you are teaching a computer to recognize cats: instead of telling it to look for whiskers, ears, and tails, you show it thousands of cat pictures. The computer finds common patterns on its own and learns how to recognize a cat. This is the essence of deep learning.
Deep learning powers many applications and services that enhance automation, performing analytical and physical tasks without human intervention. Deep learning helps with image classification, language translation, and speech recognition. Deep learning is used to solve any pattern recognition problem without human intervention.
Technically, deep learning uses something called "neural networks" inspired by the human brain. Deep neural networks or DNNs are neural networks with three or more layers. In practice, most DNNs have many more layers. DNNs are trained on large amounts of data to identify and classify phenomena, recognize patterns and relationships, assess probabilities, make predictions, and make decisions.
While a single-layer neural network can provide useful, approximate predictions and decisions, these additional layers in a deep neural network help make the results more accurate and optimized. As the number of layers increases, the network becomes "deeper," allowing it to learn more complex features and perform more complex tasks.
Basic Concepts of Deep Learning
Before diving into the intricacies of deep learning algorithms and applications, it is important to understand the fundamental concepts that make this technology so revolutionary. In this section, we explore the building blocks of deep learning:
👉 1. Neural Networks
At the heart of deep learning are neural networks, which are computational models inspired by the human brain. These networks consist of interconnected nodes or "neurons" that work together to process information and make decisions. Just as different regions of our brain are responsible for different tasks, a neural network has layers designed for specific functions.
👉 2. Deep Neural Networks
What makes a neural network "deep" is the number of layers it has between the input and output. A deep neural network has multiple layers, allowing it to learn more complex features and make more accurate predictions. The "depth" of these networks is what gives deep learning its name and its ability to solve complex problems.
👉 3. Activation Functions
Activation functions in a neural network act like decision-makers. They determine which information should be passed on to the next layer. These functions allow the network to learn from data and make detailed decisions, increasing the level of complexity.
What are the Differences Between Deep Learning and Machine Learning?

Deep learning is a specialized form of machine learning, and both are part of the artificial intelligence (AI) field.
Machine learning algorithms utilize structured, labeled data to make predictions. This means that specific features are defined and organized into tables for the model from the input data.
Deep learning eliminates some of the data preprocessing involved in machine learning. These algorithms can handle and process unstructured data like text and images, automating feature extraction and reducing the dependence on experts.
For example, suppose we have a collection of photos of different pets and want to categorize them into "cats," "dogs," "hamsters," etc. Deep learning algorithms can determine which features (e.g., ears) are most important to distinguish each animal from another. In machine learning, this hierarchy of features is manually created by a human.
How Does Deep Learning Work?
Deep learning models are based on neural network architectures. A neural network inspired by the human brain consists of interconnected nodes or neurons arranged in a layered structure that associates inputs with desired outputs.
The neurons between the input and output layers of a neural network are called hidden layers. The term “deep” usually refers to the number of hidden layers in the neural network. Deep learning models can have hundreds or even thousands of hidden layers. Just as we use our brains to identify patterns and classify different types of information, we can teach neural networks to perform the same tasks on data.

The individual layers of neural networks can also be thought of as a type of filter that works from large to small, increasing the likelihood of detecting and providing the correct result. The human brain works in a similar way. Whenever we receive new information, the brain tries to compare it with known objects. The same concept is used by deep neural networks.
Neural networks enable us to perform many tasks such as clustering, classification, or regression. We can cluster or rank unlabelled data based on the similarities between examples in the data. In the case of classification, we can train the network on a labeled dataset to categorize examples into different categories.
Artificial neural networks have unique capabilities that allow deep learning models to solve tasks that machine learning models could never solve.
All recent developments in artificial intelligence are based on deep learning. Without deep learning, we wouldn’t have self-driving cars, chatbots, or personal assistants like Alexa and Siri. Netflix wouldn’t have any idea which movies to recommend.
When Did Deep Learning Emerge?
The concept of machine learning emerged in the 1950s with the proposal of British mathematician Alan Turing. Later, Arthur Samuel introduced machine learning with his first computer learning program. Arthur Samuel’s program had the computer check what was played each time, always trying to find better ways, correcting errors, and looking for ways to learn from this data. In the following years, various machine learning techniques became popular.
In 2001, a machine learning algorithm named Adaboost was developed to detect faces in images in real-time. The most significant advancement for neural networks occurred with the introduction of a large amount of labeled data through a database called ImageNet, which made a vast amount of labeled data available.
Mass collaboration replaced the cumbersome task of manually labeling images, providing networks with an almost unlimited source of training material. Over the years, technology companies have made deep learning libraries open source.
Why is Deep Learning Important?
The reasons why deep learning is so popular are:
- Processing Unstructured Data: Models trained on structured data can easily learn from unstructured data. This reduces the time and resources needed to standardize datasets.
- Handling Large Data: With the availability of Graphics Processing Units (GPUs), deep learning models can process large amounts of data at lightning speed.
- High Accuracy: Deep learning models provide the most accurate results in computer vision, natural language processing (NLP), and audio processing.
- Pattern Recognition: Most models require intervention from a machine learning engineer. However, deep learning models can automatically detect all kinds of patterns.
Deep Learning Applications
Deep learning applications in the real world are part of our daily lives, but in most cases, they are so well integrated into products and services that users are unaware of the complex data processing happening in the background. Here are some important deep learning applications:
- Computer Vision: Computer vision is used in autonomous vehicles to detect objects and prevent collisions. It is also used for facial recognition, pose estimation, image classification, and anomaly detection.
- Natural Language Processing (NLP): Tools like translation services, speech recognition systems, and chatbots use deep learning to effectively understand and generate human language.
- Autonomous Vehicles: Deep learning assists the computer vision systems and decision-making processes in self-driving cars, enabling the recognition of objects, navigation, and avoidance of obstacles.
- Healthcare: Deep learning is used in healthcare for diagnosing diseases from X-rays and MRI scans to predicting patient outcomes and personalizing treatments.
- Finance: Deep learning is used in the finance sector for algorithmic trading, fraud detection, customer service, and risk management.
- Recommendation Systems: Companies like Netflix, YouTube, and Spotify use deep learning to analyze user behavior and preferences to recommend movies, videos, or music.
- Robotics: Robots use deep learning to interpret their environments and learn to perform complex tasks independently.
- Agriculture: Deep learning helps in identifying plant diseases and nutrient deficiencies.
- Manufacturing: Predictive maintenance, quality control, and supply chain management in manufacturing industries are assisted by deep learning.
- Art and Music: Tools that create art or compose music independently use deep learning to analyze existing styles and create new creations.
- Voice Assistants: Siri, Alexa, and Google Assistant use deep learning to understand natural language and provide relevant responses and actions.
- Weather Forecasting: Deep learning models process data from satellites and sensors to enhance the accuracy of weather forecasts.
- Drug Discovery: Deep learning significantly reduces development time and costs by speeding up the identification of potential new drugs and predicting their efficacy.

Deep Learning Models
Deep learning models can be classified into three main types: Convolutional Neural Networks (CNN), Recurrent Neural Networks (RNN), and Transformers.
1. Convolutional Neural Networks (CNN)
Convolutional Neural Networks (CNNs) are deep learning models typically used in the analysis of visual data. These models are especially suitable for tasks such as image classification, object recognition, and extracting information from images.
CNNs consist of multiple layers that break down an image into small segments and detect features in each segment. This process is particularly effective in recognizing visual patterns because the model has a structure that progresses from simple features (like edges and colors) to more complex features (like shapes of objects).
2. Recurrent Neural Networks (RNN)
Recurrent Neural Networks (RNNs) are a type of deep learning model designed to handle sequential data. These networks are known for their ability to carry information from previous steps to the current step, especially when working with sequence data. This feature makes RNNs suitable for applications where the context over time is important, such as language processing, speech recognition, and music generation.
3. Transformers
Transformers are deep learning models that are effective in language processing tasks. Introduced in a 2017 paper titled "Attention is All You Need," they have since revolutionized the natural language processing (NLP) field. They form the foundation of large language models like BERT and ChatGPT.
Deep Learning Career
Interest is growing every day for professionals who will work in the field of artificial intelligence. Machine learning engineers are in high demand because neither data scientists nor software engineers fully possess the skills required for the machine learning field.
Career opportunities and salaries make deep learning a field worth choosing. If you want to develop yourself in the field of deep learning, you can check out our open bootcamp and meet-up events.