  Computational ghost imaging is a robust and compact system that has drawn
wide attentions over the last two decades. Multispectral imaging possesses
spatial and spectral resolving abilities, is very useful for surveying scenes
and extracting detailed information. Existing multispectral imagers mostly
utilize narrow band filters or dispersive optical devices to separate lights of
different wavelengths, and then use multiple bucket detectors or an array
detector to record them separately. Here, we propose a novel multispectral
ghost imaging method that uses one single bucket detector with multiplexed
illumination to produce colored image. The multiplexed illumination patterns
are produced by three binary encoded matrices (corresponding to red, green,
blue colored information, respectively) and random patterns. The results of
simulation and experiment have verified that our method can be effective to
recover the colored object. Our method has two major advantages: one is that
the binary encoded matrices as cipher keys can protect the security of private
contents; the other is that multispectral images are produced simultaneously by
one single-pixel detector, which significantly reduces the amount of the data
acquisition.
