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Automated glaucoma detection is an important application of retinal image analysis. Compared with segmentation based approaches, image classification based approaches have a potential of better performance. However, it still remains a challenging problem for two reasons. Firstly, due to insufficient sample size, learning effective features is difficult. Secondly, the shape variations of optic disc...
The existing clipping researches in direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) systems generally originate from insufficient DC bias and the nonlinear transmission characteristics of physical devices which will distort the system performances. In contrast to conventional clipping theories, the beneficial clipping method demonstrated in this paper aims to improve...
This paper proposes a hybrid communication system for Intelligent Transportation System (ITS) utilizing visible light and radio communications for position-based services. The directionality of light communication is used to distribute position-based keys to vehicles such that they can extract information related only to their desired lanes. The extended coverage of radio communication is used to...
In this paper, we present a novel relay system in which a radio frequency (RF) signal is relayed over optical media to provide wireless communications in RF sensitive areas. We refer to this as RF over Optical (RFoO). Different from conventional relay systems, we adopt RF band phase shift beamforming to adjust the initial phases of the RF signal before modulating it into the optical band. As a benefit,...
This is a study on the effect of reflected light on optical code-division multiple-access (CDMA) system over indoor optical wireless communication (OWC). The indoor propagation channel model which takes multiple reflecting surfaces into account was addressed. Theoretical analysis of the pulse response of direct light and reflected light is given. Bit error rate (BER) of this system is analyzed considering...
This paper presents a novel position based access scheme for indoor optical wireless communication systems. In this scheme, we apply the Intensity Modulation-Direct Detection (IM/DD) with Quadrature Phase Shift Keying (QPSK) modulation. The I (in-phase) and Q (Quadrature) signal are transmitted separately in Additive White Gaussian Noise (AWGN) channel. The probability of error is analyzed with consideration...
We propose a position-based diversity transmission scheme for indoor optical wireless communication. In our scheme, the I (in-phase) and Q (Quadrature) signal of QPSK (quaternary phase-shift keying) modulation are transmitted separately to obtain a secure position-based transmission. We analyze probability of error with different mode numbers of the radiation lobe of Lambertian source, and position...
We present a relay system which uses RF over Optical (RFoO) to provide wireless communications in RF sensitive areas. Different from other relay systems, we adopt RF band phase shift beamforming to adjust phases of RF signal before modulating it into an optical band. Benefitting from it, the energy of transmitted signal is able to be concentrated in desired areas. In the designed system, the relay...
This paper presents an optical intensity-modulated direct-detection (IM/DD) based relay scheme for indoor optical wireless communication system. Multiple distributed optical relay links are set up between relay stations (RS) and mobile terminals (MT) to create multiple safe signal propagation links for wireless communication so that at least one link is available for data streaming. Different from...
This paper presents a wireless relay scheme for indoor healthcare communication system, in which an optical relay link, instead of a traditional radio frequency (RF) relay link, is established between the relay station (RS) and the mobile terminal (MT). To simplify the structures of RS and the additional optical parts that shall be installed in the MT, the subcarrier-modulation based intensity-modulated...
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