I. Introduction
Accurate reconstruction of large-scale outdoor scenes in three-dimensional (3D) color models is essential for various applications, including geographic surveying, urban planning, smart cities, digital twin cities, and environmental protection. However, outdoor scenes present unique challenges due to their complex and dynamic nature. One of the challenges arises from the sheer size and complexity of outdoor environments. These scenes often consist of numerous objects with diverse shapes and textures, making it difficult to capture and reconstruct them accurately. Moreover, outdoor scenes are subject to changing illumination conditions, which can affect the color and appearance of objects. Additionally, the presence of occlusions caused by trees, buildings, or other obstacles further complicates the reconstruction process.