UV-SAM: Adapting Segment Anything Model for Urban Village Identification

TL;DR

This paper introduces UV-SAM, a novel method that adapts the Segment Anything Model for precise boundary detection of urban villages from satellite images, aiding sustainable urban development analysis.

Contribution

UV-SAM is the first approach to accurately delineate urban village boundaries using vision foundation models, combining semantic segmentation with SAM for improved accuracy.

Findings

UV-SAM outperforms existing baselines in boundary detection accuracy.

Urban villages in China are decreasing in number and area over recent years.

The method provides valuable insights into urban development trends.

Abstract

Urban villages, defined as informal residential areas in or around urban centers, are characterized by inadequate infrastructures and poor living conditions, closely related to the Sustainable Development Goals (SDGs) on poverty, adequate housing, and sustainable cities. Traditionally, governments heavily depend on field survey methods to monitor the urban villages, which however are time-consuming, labor-intensive, and possibly delayed. Thanks to widely available and timely updated satellite images, recent studies develop computer vision techniques to detect urban villages efficiently. However, existing studies either focus on simple urban village image classification or fail to provide accurate boundary information. To accurately identify urban village boundaries from satellite images, we harness the power of the vision foundation model and adapt the Segment Anything Model (SAM) to urban village segmentation, named UV-SAM. Specifically, UV-SAM first leverages a small-sized semantic segmentation model to produce mixed prompts for urban villages, including mask, bounding box, and image representations, which are then fed into SAM for fine-grained boundary identification. Extensive experimental results on two datasets in China demonstrate that UV-SAM outperforms existing baselines, and identification results over multiple years show that both the number and area of urban villages are decreasing over time, providing deeper insights into the development trends of urban villages and sheds light on the vision foundation models for sustainable cities. The dataset and codes of this study are available at https://github.com/tsinghua-fib-lab/UV-SAM.