2.3. Manipulation of smartphone gadget
The smartphone-adaptable lightproof case was constructed for
complete protection from external light during the image acquisition
process. A lightproof acryl case was bonded on a conventional
smartphone case that covers the rear of the phone, along with
a holder for the PAD and a reflection film, dispersion film, and
trigonal prism. A combination of reflection and dispersion films
was employed to spread light uniformly within the lightproof case
during image acquisition using the smartphone-embedded lightemitting
diode (LED) flash as a single light source. The optical
signal from the PAD was registered on the smartphone CCD camera
through the trigonal prism.