  FlatCam is a thin form-factor lensless camera that consists of a coded mask
placed on top of a bare, conventional sensor array. Unlike a traditional,
lens-based camera where an image of the scene is directly recorded on the
sensor pixels, each pixel in FlatCam records a linear combination of light from
multiple scene elements. A computational algorithm is then used to demultiplex
the recorded measurements and reconstruct an image of the scene. FlatCam is an
instance of a coded aperture imaging system; however, unlike the vast majority
of related work, we place the coded mask extremely close to the image sensor
that can enable a thin system. We employ a separable mask to ensure that both
calibration and image reconstruction are scalable in terms of memory
requirements and computational complexity. We demonstrate the potential of the
FlatCam design using two prototypes: one at visible wavelengths and one at
infrared wavelengths.
