What Is Depth Estimation in Computer Vision?

Depth estimation in computer vision involves predicting the distance between a camera and objects within a scene, transforming 2D images into 3D spatial understanding through a depth map where each pixel value indicates distance. This capability is crucial for applications such as safety alerts, robotics navigation, and measurement tasks. There are three main approaches to depth estimation: monocular, stereo, and active sensors like Lidar. Monocular depth estimation uses a single camera and relies on neural networks to interpret visual cues, offering relative depth that can be converted to metric depth through calibration. Stereo depth estimation involves two cameras capturing a scene from different angles to produce metric depth based on known baseline distances, while active sensors, such as Lidar, directly measure depth by emitting and analyzing light returns, useful for long-range and low-light conditions. Advances in models like Depth Anything 3 and upcoming iterations such as YOLO-Depth and YOLO-StereoDepth enhance the accessibility and accuracy of depth estimation, allowing for seamless integration into existing workflows and systems.