Previous studies have demonstrated the feasibility of such
systems and have addressed the effects of single distortions like
linear misalignment [9], defocus blur [10] and vignetting [11]
on the modulation methods under consideration, but they have
not provided a comparative assessment of these systems in a
controlled environment. Moreover, no comparisons were made
in case of LCD camera motions which greatly affect the performance
of the system in applications that involve handheld
camera-phone receivers. As a consequence, this study introduces
DPSK-OFDM as a means of mitigating LCD camera motion
distortions and sets a series of simulations based on mathematical
modeling for blur and motion on the received images in
a way that the distortion would be the same for PAM(Pulse Amplitude
Modulation), QPSK-OFDM and DPSK-OFDM modulations.
As a result, a reliable comparison can be made between
these major modulation methods regardless of other parameters
affecting the performance of such practical systems.