PSALM: Pixelwise SegmentAtion with Large Multi-Modal Model
Zheng Zhang, Yeyao Ma, Enming Zhang, Xiang Bai
TL;DR
PSALM expands Large Multimodal Models to pixelwise segmentation by introducing a mask decoder and a flexible input schema that unifies images, task instructions, condition prompts, and mask tokens. A Mask Generator uses multi‑level visual features, mask tokens, and condition embeddings, guided by a bipartite matching loss $L = L_{mask} + L_{cls}$, enabling joint training across COCO Panoptic, RefCOCO variants, and COCO-Interactive, with strong zero-shot performance on open-vocabulary segmentation, generalized referring segmentation, and video object segmentation. Built on a Swin-based visual encoder and a Phi‑1.5 LLM, PSALM performs vision-language alignment before joint training, decouples mask proposal from classification for efficiency, and demonstrates robust generalization with a task-conditional prompting strategy. The work advances a GPT-like moment in computer vision by showing that a single LMM-based system can handle diverse segmentation tasks, improve cross-task performance through joint training, and generalize to unseen tasks without task-specific fine-tuning, while releasing code and pretrained models for the community.
Abstract
PSALM is a powerful extension of the Large Multi-modal Model (LMM) to address the segmentation task challenges. To overcome the limitation of the LMM being limited to textual output, PSALM incorporates a mask decoder and a well-designed input schema to handle a variety of segmentation tasks. This schema includes images, task instructions, conditional prompts, and mask tokens, which enable the model to generate and classify segmentation masks effectively. The flexible design of PSALM supports joint training across multiple datasets and tasks, leading to improved performance and task generalization. PSALM achieves superior results on several benchmarks, such as RefCOCO/RefCOCO+/RefCOCOg, COCO Panoptic Segmentation, and COCO-Interactive, and further exhibits zero-shot capabilities on unseen tasks, such as open-vocabulary segmentation, generalized referring expression segmentation and video object segmentation, making a significant step towards a GPT moment in computer vision. Through extensive experiments, PSALM demonstrates its potential to transform the domain of image segmentation, leveraging the robust visual understanding capabilities of LMMs as seen in natural language processing. Code and models are available at https://github.com/zamling/PSALM.
