ImPoster: Text and Frequency Guidance for Subject Driven Action Personalization using Diffusion Models
Divya Kothandaraman, Kuldeep Kulkarni, Sumit Shekhar, Balaji Vasan Srinivasan, Dinesh Manocha
TL;DR
ImPoster tackles the problem of generating a target image of a source subject performing a driving action specified by a driving image and text, using only a single source-driving pair in an unsupervised setting. The method fine-tunes a pretrained diffusion model on the pair and employs a two-stage inference strategy: first guiding the denoising toward the driving image manifold to encode the action, then toward the target text to encode the subject, reinforced at every step by frequency guidance in the Fourier domain. Frequency guidance combines amplitude and phase cues, with $G_a$ aligning source-subject characteristics and $G_p$ preserving driving-pose, implemented through latent updates $ ilde{z_t} = z_t - s_a abla_{z_t}G_a - s_p abla_{z_t}G_p$. The authors contribute (i) a formal task definition and a diffusion-based solution, (ii) a 120-pair dataset and a new Phase score metric, and (iii) extensive experiments showing gains over baselines and ablations. This work enables controllable, pose-specific personalization and lays groundwork for future extensions to video and multi-subject scenarios while highlighting societal implications of realistic synthetic imagery.
Abstract
We present ImPoster, a novel algorithm for generating a target image of a 'source' subject performing a 'driving' action. The inputs to our algorithm are a single pair of a source image with the subject that we wish to edit and a driving image with a subject of an arbitrary class performing the driving action, along with the text descriptions of the two images. Our approach is completely unsupervised and does not require any access to additional annotations like keypoints or pose. Our approach builds on a pretrained text-to-image latent diffusion model and learns the characteristics of the source and the driving image by finetuning the diffusion model for a small number of iterations. At inference time, ImPoster performs step-wise text prompting i.e. it denoises by first moving in the direction of the image manifold corresponding to the driving image followed by the direction of the image manifold corresponding to the text description of the desired target image. We propose a novel diffusion guidance formulation, image frequency guidance, to steer the generation towards the manifold of the source subject and the driving action at every step of the inference denoising. Our frequency guidance formulations are derived from the frequency domain properties of images. We extensively evaluate ImPoster on a diverse set of source-driving image pairs to demonstrate improvements over baselines. To the best of our knowledge, ImPoster is the first approach towards achieving both subject-driven as well as action-driven image personalization. Code and data is available at https://github.com/divyakraman/ImPosterDiffusion2024.
