ControlNet

ControlNet can best be described by the the very scientists who developed it: "We present a neural network structure, ControlNet, to control pretrained large diffusion models to support additional input conditions. The ControlNet learns task-specific conditions in an end-to-end way, and the learning is robust even when the training dataset is small (< 50k)." https://arxiv.org/abs/2302.05543

In other words, in addition to the word prompts and other numeric parametric inputs, the user can introduce an additional model to further indicate the desired output. There are many different ways this is done. The important point is that whereas before, users were working with one single model (a) and manually adjusting parameters, with ControlNet users are introducing an additional small model (b) that has much more capabilities of influencing the outputs.

ControlNet Diagram

Control Types

Canny

Canny detects the edges of objects in an image. It produces a layout for the output follow. Works well with single objects or images with very simple backgrounds.

Canny Example