Abstract:Spectral imaging can simultaneously obtain spatial and spectral information. Based on the abundant information in spectral images, spectral imaging is extensively employed in scientific and industrial research. However, the applications of spectral imaging systems in many fields are limited due to the characteristics of bulky optical systems, movable parts, and long exposure time. Recent years have seen the spectral imaging systems’ development in miniaturization and snapshot imaging. The principle and classification of spectral imaging are introduced. A review is given to introduce snapshot optical spectrometers based on diffractive optical element encoding, coded aperture, broadband encoding filters from its basic principles, methods, and experimental implementation. The challenging problems as well as future applications, and development are also discussed.