Local feature matching from detector-based to detector-free: a survey

Local feature matching has been a critical task in computer vision applications. In the early days of computer vision, local feature matching relied heavily on detector-based methods, where keypoint detectors were used to extract and describe the salient features of an image. However, with the advent of deep learning, detector-free methods that do not rely on keypoint detection have become increasingly popular. These methods directly learn feature descriptors from the image data, leading to improved performance and faster computation times. In this review, we explore the evolution of local feature matching from detector-based to detector-free methods, discussing the advantages and disadvantages of each approach and highlighting the recent advancements in the field. We also discuss the challenges and opportunities for future research in this area.