A video-rate hyperspectral imager for monitoring dynamic targets

Spectral imaging technology has been widely applied in many fields such as remoting sensing, biology, food testing, etc. However, most traditional imaging spectrometers have to scan in either spatial or spectral domain to obtain the full spatial-spectral information, which sacrifice the temporal resolution. In comparison, snapshot spectral imagers capture a 2D spatial and 1D spectral data cube in a single frame, which have great advantages in monitoring the spectrum of dynamic targets. In this paper, we report a video-rate hyperspectral imager with 60 bands based on a telecentric light field imaging system (LFIS). We analyze the degradation of the spectral image quality caused by the chromatic aberration of the fore-optics and propose a tighter constraint on the design metric of the chromatic focal shift. Then we design and customize the fore-optics that can fulfill the constrain. The spectral filter array (SFA) is densely arranged and coated on the sapphire glass to improve the number of spectral channels and eliminate the effect of uneven glue. Imaging experiments are conducted to demonstrate the capability of acquiring the spectral information of the dynamic scene using our designed video imager. The dynamic imaging experiment has been performed on a burning flame scene with a maximum acquisition rate of 50fps. The results indicate that our prototype has important application prospects in target identification, moving target tracking, dynamic spectrum monitoring, etc.