Biomedical Engineering Reference
In-Depth Information
Fig. 4.2
A schematic drawing (
left
) and a photograph (
right
) of a lensfree telemedicine micro-
scope that employs a single LED butt-coupled to a large pinhole (diameter
0:1 mm) and a CMOS
sensor. The cylindrical structure is a simple hollow tube within which the spatially filtered LED
light propagates before impinging on the samples, which are loaded onto the sensor chip using the
sample tray. Light tubes of different lengths can be interchangeably utilized to adjust the degree of
spatial coherence at the sensor plane
Fig. 4.3
Shows the measured holograms (using the lensfree microscope of Fig.
4.2
) and the corre-
sponding reconstructed lensfree images of different types of micro-objects including microbeads,
RBCs, WBCs, platelets, and
G. lamblia.
For visual comparison, conventional microscope images
of the same objects obtained with a 40
objective lens (NA: 0.65) are also presented
To demonstrate the potential of this platform for global health applications, we
imaged various types of micro-objects such as red blood cells (RBC), white blood
cells (WBC), platelets, microparticles, and
Giardia lamblia
cysts (
G. lamblia:
a
waterborne parasite), using the imaging platform shown in Fig.
4.2
.Aspresentedin
Fig.
4.3
, the lensfree images obtained with our telemedicine microscope compare
successfully against the conventional bright-field microscope images of the same
samples and provide subcellular structural details, which can be particularly useful
for cytometry applications [
10
,
14
]. It should be noted that these images are cropped
