On-device diffusion plugins for conditioned text-to-image technology – Google Analysis Weblog

In recent times, diffusion models have proven nice success in text-to-image technology, reaching excessive picture high quality, improved inference efficiency, and increasing our artistic inspiration. However, it’s nonetheless difficult to effectively management the technology, particularly with situations which might be tough to explain with textual content.

In the present day, we announce MediaPipe diffusion plugins, which allow controllable text-to-image technology to be run on-device. Increasing upon our prior work on GPU inference for on-device giant generative fashions, we introduce new low-cost options for controllable text-to-image technology that may be plugged into current diffusion fashions and their Low-Rank Adaptation (LoRA) variants.

Textual content-to-image technology with management plugins working on-device.

Background

With diffusion fashions, picture technology is modeled as an iterative denoising course of. Ranging from a noise picture, at every step, the diffusion mannequin steadily denoises the picture to disclose a picture of the goal idea. Analysis exhibits that leveraging language understanding through textual content prompts can tremendously enhance picture technology. For text-to-image technology, the textual content embedding is linked to the mannequin through cross-attention layers. But, some data is tough to explain by textual content prompts, e.g., the place and pose of an object. To handle this drawback, researchers add extra fashions into the diffusion to inject management data from a situation picture.

Widespread approaches for managed text-to-image technology embody Plug-and-Play, ControlNet, and T2I Adapter. Plug-and-Play applies a broadly used denoising diffusion implicit mannequin (DDIM) inversion strategy that reverses the technology course of ranging from an enter picture to derive an preliminary noise enter, after which employs a duplicate of the diffusion mannequin (860M parameters for Steady Diffusion 1.5) to encode the situation from an enter picture. Plug-and-Play extracts spatial options with self-attention from the copied diffusion, and injects them into the text-to-image diffusion. ControlNet creates a trainable copy of the encoder of a diffusion mannequin, which connects through a convolution layer with zero-initialized parameters to encode conditioning data that’s conveyed to the decoder layers. Nonetheless, in consequence, the scale is giant, half that of the diffusion mannequin (430M parameters for Steady Diffusion 1.5). T2I Adapter is a smaller community (77M parameters) and achieves comparable results in controllable technology. T2I Adapter solely takes the situation picture as enter, and its output is shared throughout all diffusion iterations. But, the adapter mannequin will not be designed for moveable gadgets.

The MediaPipe diffusion plugins

To make conditioned technology environment friendly, customizable, and scalable, we design the MediaPipe diffusion plugin as a separate community that’s:

• Plugable: It may be simply linked to a pre-trained base mannequin.
• Educated from scratch: It doesn’t use pre-trained weights from the bottom mannequin.
• Transportable: It runs outdoors the bottom mannequin on cellular gadgets, with negligible price in comparison with the bottom mannequin inference.

The MediaPipe diffusion plugin is a transportable on-device mannequin for text-to-image technology. It extracts multiscale options from a conditioning picture, that are added to the encoder of a diffusion mannequin at corresponding ranges. When connecting to a text-to-image diffusion mannequin, the plugin mannequin can present an additional conditioning sign to the picture technology. We design the plugin community to be a light-weight mannequin with solely 6M parameters. It makes use of depth-wise convolutions and inverted bottlenecks from MobileNetv2 for quick inference on cellular gadgets.

Overview of the MediaPipe diffusion mannequin plugin. The plugin is a separate community, whose output will be plugged right into a pre-trained text-to-image technology mannequin. Options extracted by the plugin are utilized to the related downsampling layer of the diffusion mannequin (blue).

Not like ControlNet, we inject the identical management options in all diffusion iterations. That’s, we solely run the plugin as soon as for one picture technology, which saves computation. We illustrate some intermediate outcomes of a diffusion course of under. The management is efficient at each diffusion step and permits managed technology even at early steps. Extra iterations enhance the alignment of the picture with the textual content immediate and generate extra element.

Illustration of the technology course of utilizing the MediaPipe diffusion plugin.

Examples

On this work, we developed plugins for a diffusion-based text-to-image technology mannequin with MediaPipe Face Landmark, MediaPipe Holistic Landmark, depth maps, and Canny edge. For every process, we choose about 100K photos from a web-scale image-text dataset, and compute management indicators utilizing corresponding MediaPipe options. We use refined captions from PaLI for coaching the plugins.

Face Landmark

The MediaPipe Face Landmarker process computes 478 landmarks (with consideration) of a human face. We use the drawing utils in MediaPipe to render a face, together with face contour, mouth, eyes, eyebrows, and irises, with totally different colours. The next desk exhibits randomly generated samples by conditioning on face mesh and prompts. As a comparability, each ControlNet and Plugin can management text-to-image technology with given situations.

Face-landmark plugin for text-to-image technology, in contrast with ControlNet.

Holistic Landmark

MediaPipe Holistic Landmarker process contains landmarks of physique pose, arms, and face mesh. Under, we generate varied stylized photos by conditioning on the holistic options.

Holistic-landmark plugin for text-to-image technology.

Depth

Depth-plugin for text-to-image technology.

Canny Edge

Canny-edge plugin for text-to-image technology.

Analysis

We conduct a quantitative research of the face landmark plugin to exhibit the mannequin’s efficiency. The analysis dataset accommodates 5K human photos. We evaluate the technology high quality as measured by the broadly used metrics, Fréchet Inception Distance (FID) and CLIP scores. The bottom mannequin is a pre-trained text-to-image diffusion mannequin. We use Stable Diffusion v1.5 right here.

As proven within the following desk, each ControlNet and the MediaPipe diffusion plugin produce a lot better pattern high quality than the bottom mannequin, when it comes to FID and CLIP scores. Not like ControlNet, which must run at each diffusion step, the MediaPipe plugin solely runs as soon as for every picture generated. We measured the efficiency of the three fashions on a server machine (with Nvidia V100 GPU) and a cell phone (Galaxy S23). On the server, we run all three fashions with 50 diffusion steps, and on cellular, we run 20 diffusion steps utilizing the MediaPipe image generation app. In contrast with ControlNet, the MediaPipe plugin exhibits a transparent benefit in inference effectivity whereas preserving the pattern high quality.

We take a look at the efficiency of the plugin on a variety of cellular gadgets from mid-tier to high-end. We checklist the outcomes on some consultant gadgets within the following desk, protecting each Android and iOS.

Conclusion

On this work, we current MediaPipe, a transportable plugin for conditioned text-to-image technology. It injects options extracted from a situation picture to a diffusion mannequin, and consequently controls the picture technology. Transportable plugins will be linked to pre-trained diffusion fashions working on servers or gadgets. By working text-to-image technology and plugins absolutely on-device, we allow extra versatile functions of generative AI.

Acknowledgments

We’d prefer to thank all staff members who contributed to this work: Raman Sarokin and Juhyun Lee for the GPU inference resolution; Khanh LeViet, Chuo-Ling Chang, Andrei Kulik, and Matthias Grundmann for management. Particular due to Jiuqiang Tang, Joe Zou and Lu wang, who made this expertise and all of the demos working on-device.