Has 3D finally come of age? ——An introduction to 3D structured-light sensor

Three-dimensional (3D) imaging and sensing technologies, as valuable information acquisition tools for perceiving the real 3D world, provide data bases for the reconstruction of the geometric shape of objects and subsequent 3D modeling, detection, and recognition. Recently the development of computer vision and optoelectronic imaging technology, as well as the growing demand for 3D technologies in consumer electronics and personal authentication, have promoted the thriving growth of 3D imaging and sensing technologies. After the imaging revolution from monochrome to color, low resolution to high resolution, and static image to dynamic video, the transition of the camera from 2D to 3D will become the new \"fourth imaging revolution.\" This issue of \"Infrared and Laser Engineering\" organizes a special topic on \"Optical 3D Imaging and Sensing\", which contains 20 high-quality articles, including 15 review papers and 5 research papers. These papers systematically introduce the research progress or trends of the cutting-edge research topics in the field of optical 3D imaging and sensing, and their themes comprehensively cover the current hot research directions in the field of 3D optical imaging: structured-light 3D imaging, fringe projection profilometry, interferometry, phase measuring deflectometry, 3D display technologies (such as holographic display, and integral/light field display), and the interdisciplinary fields of 3D sensing technologies and computational imaging technologies (such as 3D ghost imaging). As the preface of this issue, this paper summarizes the typical 3D sensing technologies and focuses on the current status, key technologies, and typical applications of the 3D structured-light sensor technologies, discusses its existing challenges, and looks forward to its future development directions.