Monocular Depth Estimation: A Survey

Monocular depth estimation is an ill-posed task in computer vision, which holds great significance in the fields such as artificial intelligence, virtual reality, augmented reality, path planning, unmanned driving, and navigation guidance. The primary objective of monocular depth estimation is to predict the depth value of each pixel or infer depth information, given just a single red-green-blue (RGB) image as input. Traditional monocular depth estimation methods rely on limited depth cues, such as strict scene conditions. With the significant advancements in computer vision and artificial intelligence, monocular depth estimation using deep learning has been extensively researched and has yielded substantial results. This paper presents a comprehensive survey of monocular depth estimation. Firstly, we give an overall introduction to monocular depth estimation and explain it from traditional and deep learning-based methods, respectively. To specify, supervised, self-supervised and semi-supervised models are described in detail in deep learning-based methods. Additionally, we introduce publicly available benchmark datasets and evaluation metrics commonly used in this field. Finally, we discuss the current challenges and promising prospects for the development of monocular depth estimation.