Irfanud Din

Energy-Efficient Brightness Control and Data Transmission for Visible Light Communication

This letter considers the efficient utilization of energy in a visible light communication (VLC) system. A joint brightness control and data transmission are presented to reduce the total power consumption while satisfying lighting and communication requirements. An optimization problem is formulated to determine the optimal parameters for the input waveform of light emitting diode (LED) lamps; this problem reduces the total energy consumption of the LED lamps while ensuring the desired brightness and communication link quality. The simulation results show that the proposed scheme increases the energy efficiency of the VLC system.

Projector Calibration for Pattern Projection Systems

In this paper we proposed a method for geometric calibration of a projector. This method makes use of a calibrated camera to calibrate the projector. Since the projector works inversely with a camera i.e., it projects the image instead of capturing it, so it can be considered as a reverse camera. The projector is calibrated with the help of a calibrated camera using two types of chessboard, a printed chessboard and a projected chessboard by the projector. The object points of the projected chessboard pattern are measured with the help of calibrated camera and the image points are directly acquired from the chessboard pattern to be projected. Then using these object points and image points the projector is calibrated. Once the projector calibration is done, the transformation matrices (from projector to screen, from camera to screen and from camera to projector) are determined which are used for the reconstruction of the 3D geometry.

Joint blind and light control for lighting energy reduction while satisfying light level and anti-glare requirements

This paper presents a joint blind and light control scheme for lighting energy optimization in a lighting control system. The proposed scheme utilizes the maximum available daylight without any glare and reduces lighting energy consumption while satisfying the user’s light level requirements. The optimal blind tilt angle that transmits the maximum available daylight without any glare is computed based on the sun’s altitude and the window ’ s orientation, and an optimization problem is formulated that minimizes the required artificial lighting energy to satisfy the user’s lighting requirements. The simulation results show that, relative to conventional lighting control schemes, the proposed scheme achieves improvements in lighting energy consumption while satisfying the anti-glare and user’s light level requirements.

Performance analysis of SC-L-PPM for energy-efficient visible light communication

Subcarrier pulse positions modulation (SC-PPM) is a standardized modulation method for visible light communication (VLC). Because of its robust nature SC-PPM is utilized in VLC for data modulation as well as brightness control. In this work we investigate the performance of different variants of SC-PPM for brightness control and communication quality. Results based on numerical analysis are presented to analyze brightness control and communication performance of variants of SC-PPM schemes.

Joint Power and Beam Angle Control for Energy Efficiency in Lighting Control Systems

This paper considers an energy-efficient utilization in lighting control systems (LCS). A joint power and beam angle control in LCS is proposed that reduces energy consumption while satisfying the user’s lighting requirements. A problem to find the optimal pair of power and the beam angle of luminaries is formulated and an algorithm to find the optimal solution is suggested. The simulation results show that the proposed scheme achieves considerable improvement in energy savings compared to conventional lighting energy saving scheme which does not consider the beam angle control.

A proportional fair spectrum allocation for wireless heterogeneous networks

This paper proposes a cost-efficient proportional fair (PF) scheduling algorithm for heterogeneous networks. For the networks with different access cost, the scheduler assigns users to the networks to maximize the sum of logarithmic average cost-efficiency.

An opportunistic spectrum sharing scheme for dense small cell networks.

Network densification with small cells deployment is regarded as one of the promising approaches to meet a huge demand of rapidly increasing wireless capacity. Such an approach can lead a dramatic increase of wireless capacity, but the interference issue still exists, which could be even more severe when the cells are too closely placed. This paper proposes an efficient spectrum sharing for a dense small cell network, where a user is usually communicable with multiple cells. Assuming either a simultaneous or a dedicated manner of the spectrum usage, an optimal spectrum sharing problem in order that the total system throughput is e maximized while user specific required data rate can be guaranteed. The proposed solution optimally determines the time portion of each spectrum usage manner, while satisfying the intended spectrum sharing goal.

Parallel phase unwrapping in 3D shape measurement using digital fringe projection technique

Phase unwrapping is used to get absolute phase from the wrapped phase image and remove 2π discontinuities. It is computational extensive process. It requires a lot of iterations, first in one dimension of the image and then in the other dimension, to unwrap the phase. The primary limitation of the phase unwrapping is that it is a path dependant process which can only be executed sequentially. In this paper we have developed a new method for the parallel processing of path dependant phase unwrapping. In this proposed method different blocks of image are executed parallely by separate threads independent of each other. The algorithm used in this paper is Itoh for phase unwrapping. The results achieved by parallel processing of phase unwrapping are 99% better as compared to the sequential processing.