What is a Generative Adversarial Network (GAN)? Explained

by Chris Von Wilpert, BBusMan • Last updated November 23, 2023

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What is a generative adversarial network?

Imagine a friendly competition between two digital artists: one creates amazing pictures, while the other is an expert at spotting which ones are real or fake. They keep challenging each other to improve their skills. This “game” represents Generative Adversarial Networks (GANs), where two AI systems — "the Generator" making realistic images and "the Discriminator" judging them — learn from each other's moves. As they play this game, both get better and better. So if you want incredibly lifelike images or impressive deepfakes that make people wonder what's real, it's time to explore the world of GANs.

Generative adversarial network fast facts

  • GANs (Generative Adversarial Network) excel in creating ultra-realistic images.

  • Deep learning covers various AI models — GANs specifically focus on generating new data.

  • GANs work with two neural networks: one that makes new data and another that judges if it's real or not.

  • MidJourney leverages GANs to turn text prompts into stunning, unique artworks.

  • ChatGPT, unlike GANs, relies on transformer networks for advanced language processing.

What is the purpose of GAN?

A Generative Adversarial Network, or GAN, is like a smart, creative duo in the world of artificial intelligence. Developed by Ian Goodfellow and his team, these networks are brilliant at making new images that look real, even though they're computer-generated. You have two parts in a GAN — the generator and the discriminator, kind of like an artist and an art critic.

The generator is like a digital artist. It creates images from scratch, using random noise and data as its canvas and brushes. Its goal? To make pictures so good they look like they could be real. 

On the other side, the discriminator acts as the art critic. It looks at both the generator's creations and real images and tries to tell them apart. It's constantly guessing which ones are genuine and which ones are AI-made.

This back-and-forth between the generator and discriminator is a training session, where both parties learn and get better over time. The generator tries to trick the discriminator with ever-more realistic images, while the discriminator becomes sharper at spotting fakes. Through this process, GANs become great at creating believable images, from art to realistic-looking photos, and can even help in areas like medical imaging. They're a prime example of how AI can not only learn but also creatively produce new things that are useful and sometimes, even beautiful.

A flowchart showing the architecture of a GAN, highlighting the cycle between the generator receiving random input and the discriminator assessing the generated sample, with the process of backpropagation to refine the models. Photograph: Google for Developers.

How is GAN trained?

Training a Generative Adversarial Network (GAN) is a unique and interesting process, involving a kind of tug-of-war between two neural networks. This training involves two key players: the generator and the discriminator, each with a different role and objective.

The generator starts the process. It's like an aspiring artist trying to create convincing fake images. It takes random noise as input and generates images. These images might not be perfect at first, akin to rough sketches. The generator's goal is to eventually produce images so realistic that they can fool the discriminator. Think of it as a forger trying to create a masterpiece indistinguishable from an original.

Next enters the discriminator, the skeptical art critic. It examines both the generator's creations and real images from the training dataset. Its job is to figure out which images are real and which are fakes produced by the generator. Every time the discriminator makes a correct guess, it gets better at distinguishing real from fake. This creates a feedback loop for the generator, giving it clues on how to improve its creations.

This training is a dynamic dance. As the generator improves, creating more realistic images, the discriminator also sharpens its ability to tell real from fake. This competitive training continues until the generator gets so good that the discriminator can't easily tell the difference between real and generated images. This point is where the GAN has effectively 'learned' to produce realistic outputs, whether they're images, sounds, or other types of data.

What is generative AI vs AI?

AI (artificial intelligence) is a broad term that encompasses any computer system or program that can perform tasks that typically would require human intelligence. This includes understanding natural language, recognizing images, making decisions, and solving problems. AI can be as simple as a chess program or as complex as self-driving cars. It's a general category that includes all kinds of smart technologies that mimic human abilities.

Generative AI, on the other hand, is a specialized subset of AI. It focuses on creating new content — be it text, images, music, or even video — that didn't exist before. Generative AI systems learn from a large amount of existing data and then use that learning to generate new, original material. A classic example of generative AI is the Generative Adversarial Network (GAN), which can create new images that look strikingly real. The key thing about generative AI is its ability to produce something novel, rather than just analyzing or processing existing information.

Why are generative adversarial networks so popular?

Generative Adversarial Networks (GANs) have soared in popularity, and there are compelling reasons for this. Firstly, their ability to generate highly realistic and convincing data, especially images, stands out. GANs, through their unique structure of a generator and a discriminator in a competitive setup, excel at creating photorealistic images that are often indistinguishable from real ones. This has immense applications in fields like art creation, video game design, and even movie special effects, where lifelike imagery is crucial.

GANs are also incredibly versatile and have a broad range of applications beyond just image generation. They're used in style transfer (think turning a regular photo into an artwork resembling Van Gogh's style), creating realistic-sounding voices, and generating synthetic data for training other AI models. 

The underlying technology of GANs is fascinating and represents a significant leap in deep learning and neural networks. The adversarial process, where the generator and discriminator continuously challenge and improve each other, is an innovative approach to training AI models. This not only leads to high-quality outputs but also advances our understanding of machine learning processes. The excitement in the AI research community around GANs has contributed to their popularity, as they continually open new frontiers in AI development capabilities.

How do you implement GAN?

Implementing a Generative Adversarial Network (GAN) involves a series of steps, each requiring careful attention to detail. To start, you'll need a solid understanding of neural networks and access to a machine learning framework like TensorFlow or PyTorch. Here's a simplified overview of the process:

  1. Design the Networks: First, you need to design two separate neural networks: the Generator and the Discriminator. The Generator takes in random noise as input and produces data (like images). The Discriminator takes data as input and tries to determine whether it's real or fake. These networks can be built using layers of neurons, including convolutional layers, for image tasks.
  2. Prepare the Dataset: You'll need a dataset for training. If you're generating images, this could be a collection of thousands of images. The quality and diversity of your dataset significantly impact the performance of your GAN. This dataset is used to train the Discriminator to recognize real data.
  3. Train in Alternation: Training involves alternating between updating the Discriminator and the Generator. First, you train the Discriminator by showing it real images (labeling them as real) and images generated by the Generator (labeling them as fake). Then, you train the Generator to produce new images. During Generator training, you use the Discriminator's feedback to update the Generator’s ability to create realistic images. Essentially, the Generator learns to make images that the Discriminator is more likely to classify as real.

A simplified representation of a GAN, with a generator creating fake currency and a discriminator evaluating the authenticity against real currency. Photograph: Avijeet Biswal via Simplilearn.

What can I do with GAN?

Generative Adversarial Networks (GANs) are a fascinating blend of neural network models that have revolutionized the field of deep learning. At their core, GANs consist of two parts: a generator and a discriminator. The generator creates fake images, while the discriminator learns to distinguish between real and generated images. This adversarial setting enhances the quality of the generated images, making them increasingly realistic over time.

The applications of GANs are diverse and growing. In image processing, they're known for their ability to produce photorealistic images, enabling advancements in fields like fashion, architecture, and game design. For example, designers use GANs to generate new clothing styles or to visualize architectural projects with lifelike detail. In entertainment, GANs contribute to the creation of realistic 3D models and environments, enhancing the visual experience in video games and virtual reality.

Another groundbreaking area is medical imaging. GANs assist in image synthesis, helping to create detailed medical images for training and research purposes. This proves invaluable in scenarios where real medical images are scarce or where privacy concerns limit data availability. By generating realistic, yet artificial, medical images, GANs facilitate deeper research and training opportunities in healthcare, potentially leading to more accurate diagnoses and better patient outcomes.

Is GAN part of generative AI?

Absolutely, Generative Adversarial Networks (GANs) are definitely a key part of generative AI. In the world of AI, "generative" means models that can make new data points, images, sounds, or other media that look a lot like real-world stuff. GANs are a top example of this in deep learning. They create new, synthetic data that's really hard to tell apart from the real thing.

GANs work with two neural networks — the generator and the discriminator. The generator creates content, and the discriminator tries to figure out what's real and what's generated. This back-and-forth process lets GANs create realistic and believable outputs, whether in the form of pictures, sounds, or other types of data.

GANs have a big impact in generative AI. They're used for all sorts of stuff, like making lifelike images for art and design, or making up data to train machine learning models when real data is hard to get or too private. This tech has opened up lots of new possibilities in creativity and solving problems, making it a major player in today's generative AI.

Is deep learning the same as GAN?

No, deep learning and Generative Adversarial Networks (GANs) are not the same. Deep learning is a broad area in artificial intelligence that uses neural networks to mimic the way human brains operate. It's a key technology behind many advanced AI applications, like image and speech recognition, language translation, and autonomous vehicles.

GANs, on the other hand, are a specific type of deep learning model. They are known for their unique structure, which consists of two parts: a generator and a discriminator. The generator creates data (like images), and the discriminator evaluates it. The two networks work in opposition to each other, which allows GANs to generate highly realistic and detailed synthetic data.

So, while GANs are a subset of deep learning focused on generating new data, deep learning itself is a much broader field encompassing various types of neural network models for a wide range of tasks.

A diagram illustrating the process of a Generative Adversarial Network (GAN), where noise is progressively refined by a generator into a realistic image, which is then assessed by a discriminator. Om Kamath via Level Up Coding.

Does MidJourney use GAN?

MidJourney, an AI system known for creating unique images and artwork from text prompts, utilizes Generative Adversarial Networks (GANs). 

It employs an image-based GAN to analyze source images and generate unique, new versions of it, enabling the creation of artworks that are both unique and visually captivating. This approach places MidJourney within the realm of GAN applications, specifically in the field of AI-driven art generation.

GANs, as used by MidJourney, consist of two neural networks: a generator and a discriminator. These networks work together in a sort of AI tug-of-war, where the generator creates images and the discriminator evaluates them. This dynamic process is fundamental to how MidJourney operates, allowing it to generate high-quality, artistic images based on textual descriptions or prompts.

The use of GANs in MidJourney showcases the technology's versatility and ability to create visually striking and imaginative outputs from textual inputs, a testament to the evolving capabilities of generative AI in artistic and creative domains.

Is ChatGPT based on GAN?

No, ChatGPT isn't based on Generative Adversarial Networks (GANs). Instead, it's built on a different kind of neural network called a transformer, specifically designed for processing and generating language. Transformers are a type of model in deep learning known for their effectiveness in handling sequential data, like text.

GANs are more about creating realistic images or data by having two networks (a generator and a discriminator) work against each other. They're great for tasks like generating photorealistic images or creating new data samples, but they're not typically used for language-based tasks like those ChatGPT handles.

ChatGPT is trained using large amounts of text data, learning to understand and generate human-like responses. This training involves learning patterns in language, grammar, and context, which is something transformers excel at, making them the go-to choice for advanced language models like ChatGPT.

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