In general, deep generative models like GANs, VAEs, and autoregressive models handle image synthesis problems.
Given the high quality of the data they create, generative adversarial networks (GANs) have received a lot of attention in recent years.
Diffusion models are another fascinating field of study that has established itself. The fields of image, video, and voice generation have both found extensive use for both of them.
Diffusion models vs. GANs: Which Produces Better Results? Naturally, this has led to an ongoing discussion.
In the computational architecture known as the GAN, two neural networks are fought against one another to produce newly synthesized instances of data that can pass for genuine data.
Diffusion models are getting more and more popular since they provide training stability and high results for producing music and graphics.
This article will go through the diffusion model and GANs in detail, as well as how they differ from one another and a few other things.
So, what are Generative Adversarial Networks?
In order to create new, artificial instances of data that might be mistaken for genuine data, generative adversarial networks (GANs) employ two neural networks and pit them against each other (thus the “adversarial” in the name).
They are extensively utilized for speech, video, and picture creation.
GAN’s objective is to create previously undiscovered data from a specific dataset. Attempting to infer a model of the actual, unidentified underlying data distribution from the samples, does this.
Alternatively said, these networks are implicit models that attempt to learn a specific statistical distribution.
The method GAN used to discover how to accomplish this aim was novel. In fact, they produce data by playing a two-player game to develop an implicit model.
The following describes the structure:
- a Discriminator that gains the ability to differentiate between authentic and fake data
- a generator that picks up new ways to create data can trick the discriminator.
The discriminator poses as a neural network. Therefore, the generator needs to create a picture with high quality to trick it.
The fact that these generators are not trained using any output distribution is a significant distinction between autoencoder models and other models.
There are two ways to decompose the loss function of the model:
- the ability to quantify if the discriminator accurately foresees real data
- generated data is accurately predicted by a portion.
On the best feasible discriminator, this loss function is then minimized:
Generic models can therefore be thought of as distance minimization models and, if the discriminator is ideal, as divergence minimization between the true and produced distribution.
In reality, different divergences may be employed and result in various GAN training methods.
The learning dynamics, which include a trade-off between the generator and the discriminator, are challenging to follow, despite it being simple to adjust the loss function of GANs.
There are also no assurances that learning will converge. As a result, training a GAN model is difficult, since it is typical to run across problems like disappearing gradients and mode collapse (when there is no diversity in the generated samples).
Now, it’s time for Diffusion Models
The problem with GANs’ training convergence has been addressed through the development of diffusion models.
These models assume that a diffusion process is equivalent to information loss brought on by noise’s progressive interference (a gaussian noise is added at every timestep of the diffusion process).
The purpose of such a model is to determine how noise affects the information present in the sample, or, to put it another way, how much information is lost due to diffusion.
If a model can figure this out, it ought to be able to retrieve the original sample and undo the information loss that occurred.
This is accomplished through a denoising diffusion model. A forward diffusion process and a reverse diffusion process make up the two steps.
The forward diffusion process involves gradually adding Gaussian noise (i.e., the diffusion process) until the data is completely contaminated by noise.
The neural network is subsequently trained using the reverse diffusion method to learn the conditional distribution probabilities to reverse the noise.
Here you can understand more about the diffusion model.
Diffusion Model Vs GANs
Like a diffusion model, GANs produce pictures from noise.
The model is made up of a generator neural network, which begins with the noise of some informative conditioning variable, such as a class label or a text encoding.
The result should then be something that resembles a realistic image.
To create photorealistic and high-fidelity picture generations, we employ GANs. Even more realistic visuals than GANs are produced using diffusion models.
In a way, diffusion models are more accurate in describing the facts.
While a GAN takes as input random noise or a class conditioning variable and outputs a realistic sample, diffusion models are often slower, iterative, and need much more guidance.
There isn’t much room for error when denoising is applied repeatedly with the goal of returning to the original image from the noise.
Each checkpoint is passed through throughout the creation stage, and with each step, the picture might gain more and more information.
In conclusion, Due to few significant research that was only published in the 2020s and 2021, diffusion models can now outperform GANs in terms of picture synthesis.
This year, OpenAI launched DALL-E 2, an image production model that allows practitioners to employ diffusion models.
Although GANs are cutting-edge, their constraints make it challenging to scale and use them in new contexts.
In order to achieve GAN-like sample quality using likelihood-based models, a lot of work has been put into it.