Biomedical Engineering Reference
In-Depth Information
Fig. 4.8
Holograms recorded with the cell-phone microscope (Fig.
4.6
), corresponding recon-
structed images and conventional bright-field microscope images are provided for different
microparticles (3 and 7m diameter), RBCs, WBCs (monocyte and granulocytes), and
G. lamblia
cysts
for green and red pixels to be faithful to the measured amplitude values in these
high SNR pixels of the raw image. Once convergence is achieved, a complex optical
field at the hologram plane is obtained, which can be digitally back-propagated to
the object plane to reconstruct a lensfree microscopic image of the samples.
We investigated the imaging performance of our cell-phone microscope by
conducting experiments with different samples including spherical microparticles,
RBCs, WBCs, platelets, and waterborne parasites (
G. lamblia
cysts). As demon-
strated in Fig.
4.8
, the lensfree images obtained with our cell-phone microscope
correlate well with images obtained using a conventional benchtop optical micro-
scope (10
objective lens with a numerical aperture (NA) of 0.25). The spatial
resolution of our cell-phone imager is sufficiently high to reveal subcellular details
of cells, which is especially noticeable in the granulocyte images where multiple
nuclei within the WBC can be discerned. The high contrast of our lensfree images
(which is due to reconstruction of optical phase information of the specimen)
makes our approach particularly useful to image weakly scattering phase objects
as revealed by the cell-phone image of the
G. lamblia
cyst in Fig.
4.8
.
These experimental results obtained with our holographic cell-phone microscope
suggest that this platform can be utilized to perform blood analysis similar to what
has been presented in Sect.
4.3
. Moreover, an additional advantage of using a cell-
phone-integrated telemedicine microscope is the ability to wirelessly transmit the
acquired holographic data to a remote station, for example, to a computer located
in a hospital or clinic, for rapid digital processing. As demonstrated in [
11
], the raw
