  A lensfree spectral light-field fusion microscopy (LSLFM) system is presented
for enabling contrast- and resolution-enhanced imaging of biological specimens.
LSLFM consists of a pulsed multispectral lensfree microscope for capturing
interferometric light-field encodings at various wavelengths, and
Bayesian-based fusion to reconstruct a fused object light-field from the
encodings. By fusing unique object detail information captured at different
wavelengths, LSLFM can achieve improved resolution, contrast, and
signal-to-noise ratio (SNR) over a single-channel lensfree microscopy system. A
five-channel LSLFM system was developed and quantitatively evaluated to
validate the design. Experimental results demonstrated that the LSLFM system
provided SNR improvements of 6-12 dB, as well as a six-fold improvement in the
dispersion index (DI), over that achieved using a single-channel,
resolution-enhancing lensfree deconvolution microscopy system or its
multi-wavelength counterpart. Furthermore, the LSLFM system achieved an
increase in numerical aperture (NA) of ~16% over a single-channel
resolution-enhancing lensfree deconvolution microscopy system at the
highest-resolution wavelength used in the study. Samples of Staurastrum
paradoxum, a waterborne algae, and human corneal epithelial cells were imaged
using the system to illustrate its potential for enhanced imaging of biological
specimens.
