How do AI-powered text-to-image generators like DALL·E 2, Stable Diffusion, and Midjourney Work?

Kazi Ahmed
5 min readJan 11, 2023

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In recent years, Artificial Intelligence (AI) has made significant strides in the field of image generation. Among the many tools available today, there are a few that stand out for their ability to convert text into pictures or paintings. These include DALL·E 2, Stable Diffusion, and Midjourney.

DALL·E 2, created by OpenAI, is an AI program that generates images from textual descriptions. By using over 10 billion parameter training versions of the GPT-3 transformer model, it is able to interpret natural language inputs and generate corresponding images.

Stable Diffusion is another text-to-image model that utilizes a frozen CLIP ViT-L/14 text encoder to fine-tune the model with text prompts. It separates the imaging process into a “diffusion” process during runtime. The process begins with only noise and gradually improves the image until it is entirely free of noise and closely aligns with the provided text description.

Midjourney is yet another AI-powered tool for image generation, but it excels in adapting actual art styles to create an image of any combination of things the user desires. It is particularly proficient at creating environments, particularly fantasy and sci-fi scenes, complete with dramatic lighting that looks like rendered concept art from a video game.

Overall, these three tools, DALL·E 2, Stable Diffusion, and Midjourney are some of the most notable advancements in AI image generation, each with its own unique features and capabilities. They allow for highly customized images generated based on text inputs, making the process of creating visual content faster and more efficient.

The mechanics and processes utilized by DALL·E 2

DALL·E 2, the AI image generator created by OpenAI, is a tool that can convert text inputs into images. This is accomplished through the use of two main components: the Prior, which converts the user input into a representation of an image, and the Decoder, which converts this representation into an actual photo.

The text and image embeddings used in DALL·E 2 come from another network called CLIP (Contrastive Language-Image Pre-training) also developed by OpenAI. CLIP is a neural network that returns the best caption for an input image, the opposite of what DALL·E 2 does with text-to-image conversion. The objective of CLIP is to learn the connection between the visual and textual representation of an object.

DALL·E 2’s goal is to train two models. The first, the Prior, is trained to take text labels and create CLIP image embeddings. The second, the Decoder, takes the CLIP image embeddings and produces an image. After training, the workflow for image generation follows these steps:

  1. The entered caption is transformed into a CLIP text embedding using a neural network.
  2. Prior reduces the dimensionality of the text embedding using Principal Component Analysis (PCA).
  3. Image embedding is created using the text embedding.
  4. In the decoder step, a diffusion model is used to transform the image embedding into the image.
  5. The image is upscaled from 64x64 to 256x256 and then finally to 1024x1024 using a Convolutional Neural Network.

In summary, DALL·E 2 utilizes the CLIP network to generate images based on text input through the use of two main components, the Prior, and the Decoder. The two models are trained to create an image embedding, that is then upscaled using diffusion model and CNN in order to produce the final image. The DALL·E 2 can generate images that can be very realistic and adapt to different art styles with a single text input.

The technology behind Stable Diffusion

Stable Diffusion is an advanced text-to-image synthesis technique that utilizes Latent Diffusion Models (LDM) to create images from text prompts.

Diffusion Models (DM) are a type of transformer-based generative model that take an input, such as an image, and gradually add noise over time until the image becomes unrecognizable. The model then tries to reconstruct the image to its original form, learning how to generate pictures or other data in the process.

The issue with DMs is that the more powerful models consume hundreds of GPU days and require expensive computational resources for inference. To overcome this limitation, LDMs are applied in the latent space of powerful pre-trained autoencoders.

This approach allows for optimal complexity reduction and detail preservation, resulting in significant improvements in visual fidelity. A cross-attention layer is also added to the model architecture, making the LDM a flexible generator for inputs such as text and bounding boxes, allowing for high-resolution convolution-based synthesis.

In summary, Stable Diffusion utilizes Latent Diffusion Models (LDM) to train powerful text-to-image synthesis technique, which is more efficient, while preserving details and producing high-quality images.

Midjourney’s workflow

If you’re looking for a cutting-edge tool for generating unique images, you might want to check out Midjourney. This innovative platform utilizes the power of Artificial Intelligence (AI) and Machine Learning (ML) to create stunning images from text prompts and parameters.

One of the great things about Midjourney is its ease of use. To generate an image, all you have to do is connect with the official Discord bot and enter the command ‘/imagine’ followed by your text prompt or parameters. The bot then takes care of the rest, quickly producing a beautiful, one-of-a-kind image.

Keep in mind that currently Midjourney’s platform is only accessible via their official Discord, but its an convenient way to quickly get an art done with the power of AI, So if you’re a digital artist, designer, or simply someone who appreciates the beauty of art, you’ll definitely want to check out Midjourney.

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