  With the rapid development of high-speed communication and artificial
intelligence technologies, human perception of real-world scenes is no longer
limited to the use of small Field of View (FoV) and low-dimensional scene
detection devices. Panoramic imaging emerges as the next generation of
innovative intelligent instruments for environmental perception and
measurement. However, while satisfying the need for large-FoV photographic
imaging, panoramic imaging instruments are expected to have high resolution, no
blind area, miniaturization, and multidimensional intelligent perception, and
can be combined with artificial intelligence methods towards the next
generation of intelligent instruments, enabling deeper understanding and more
holistic perception of 360-degree real-world surrounding environments.
Fortunately, recent advances in freeform surfaces, thin-plate optics, and
metasurfaces provide innovative approaches to address human perception of the
environment, offering promising ideas beyond conventional optical imaging. In
this review, we begin with introducing the basic principles of panoramic
imaging systems, and then describe the architectures, features, and functions
of various panoramic imaging systems. Afterwards, we discuss in detail the
broad application prospects and great design potential of freeform surfaces,
thin-plate optics, and metasurfaces in panoramic imaging. We then provide a
detailed analysis on how these techniques can help enhance the performance of
panoramic imaging systems. We further offer a detailed analysis of applications
of panoramic imaging in scene understanding for autonomous driving and
robotics, spanning panoramic semantic image segmentation, panoramic depth
estimation, panoramic visual localization, and so on. Finally, we cast a
perspective on future potential and research directions for panoramic imaging
instruments.
